DREL/2010 SPECTROPHOTOMETER Soil and Irrigation

49332-88
DREL/2010
SPECTROPHOTOMETER
Soil and Irrigation Water
Portable Laboratory Manual
© Hach Company, 1996. Printed in U.S.A. All rights reserved.
js/cth 12-1-96-1ED
ii
TABLE OF CONTENTS
PREFACE.............................................................................................................................. vii
SECTION 1 INTRODUCTION ............................................................................................. 1
1.1 Soil and Irrigation Water Manuals ...................................................................................... 1
1.1.1 Using This Manual........................................................................................................ 1
1.1.2 Extracting Soil Samples ................................................................................................ 1
1.1.3 Soil Extraction Guide.................................................................................................... 2
1.2 Using the Apparatus in the Kit............................................................................................ 3
1.2.1 Accurately Measuring Liquids Using Eye Droppers and Graduated Cylinders ........... 3
1.2.2 Using the Soil Scoops ................................................................................................... 3
1.2.2.1 Alternative Procedure ............................................................................................. 4
SECTION 2 SAMPLE COLLECTION AND PREPARATION......................................... 5
2.1 Soil Preparation ................................................................................................................... 5
2.1.1 Sampling, Drying, Grinding and Screening.................................................................. 5
2.1.2 Soil Sampling................................................................................................................ 5
2.1.3 Filtering Soil Extracts ................................................................................................... 6
2.1.4 Using Additional Apparatus ......................................................................................... 6
2.1.5 Example of Procedure Using Alternative Apparatus.................................................. 10
2.2 Determining the Dilution Factor ....................................................................................... 11
2.3 Conversion from ppm to lbs/acre or kg/ha........................................................................ 12
2.4 Extraction Guide ............................................................................................................... 12
2.5 Obtaining Water Samples.................................................................................................. 13
SECTION 3 SOIL EXTRACTION PROCEDURES ......................................................... 15
AQUEOUS EXTRACTION, Used for Salinity and pH ......................................................... 17
BRAY P1 (WEAK) EXTRACTION, Used for Phosphorus in Acid Soils............................. 19
BRAY P2 (STRONG) EXTRACTION, Used for Phosphorus in Acid Soils......................... 23
CALCIUM PHOSPHATE SOIL EXTRACTION, Used for Sulfate...................................... 27
CALCIUM SULFATE SOIL EXTRACTION, Used for Nitrate ........................................... 29
SATURATED CALCIUM SULFATE EXTRACTION,
Used for Gypsum Requirement and Exchangeable Sodium................................................ 31
MEHLICH 1 EXTRACTION,
Used for Calcium and Magnesium, Phosphorus, Potassium and Sodium ........................... 35
MEHLICH 2 EXTRACTION,
Used for Calcium and Magnesium, Phosphorus, Potassium and Sodium ........................... 39
NEUTRAL NORMAL AMMONIUM ACETATE EXTRACTION,
Used for Calcium and Magnesium, Potassium and Sodium................................................ 43
iii
TABLE OF CONTENTS, continued
OLSEN SODIUM BICARBONATE EXTRACTION,
Used for Phosphorus and Potassium ................................................................................... 47
POTASSIUM CHLORIDE EXTRACTION, Used for Total Exchangeable Acidity ............ 49
SATURATED SOIL PASTE, Used for pH and Soluble Salts ............................................... 51
SMP BUFFER EXTRACTION, Used for Lime Requirement............................................... 55
SECTION 4 SOIL ANALYSIS PROCEDURES................................................................ 57
SOIL ANALYSIS PROCEDURES,
4.1 Calculation of Cation Exchange Capacity and Percent Base Saturation for Soil............. 59
CALCIUM, Using EDTA with a Digital Titrator................................................................... 61
CALCIUM + MAGNESIUM, Using EDTA with a Digital Titrator...................................... 65
CALCIUM + MAGNESIUM,
Calcium and Magnesium; Calmagite Colorimetric Method ............................................... 69
GYPSUM REQUIREMENT, EDTA Titration Method Using Digital Titrator ..................... 75
LIME ESTIMATION, FREE (EXCESS), Effervescence Method......................................... 79
NITRATE, HR, Cadmium Reduction Method ....................................................................... 81
ORGANIC MATTER, Dichromate Method .......................................................................... 87
pH, Hach One Combination pH Electrode Method with an EC10 Portable Meter ................ 91
PHOSPHORUS, REACTIVE, PhosVer® 3 (Ascorbic Acid) Method .................................. 97
POTASSIUM, Tetraphenylborate Method ........................................................................... 103
SALINITY(CONDUCTIVITY), Pocket Pal™ Conductivity Tester ..................................... 111
SOLUBLE SALTS (SALINITY),
Saturated Paste Method with Pocket Pal Conductivity Tester .......................................... 115
SULFATE, SulfaVer® 4 Method .......................................................................................... 121
SULFUR REQUIREMENT, Titrimetric Sulfuric Acid Method .......................................... 129
SECTION 5 SOIL TEXTURE ESTIMATION................................................................ 133
TOTAL EXCHANGEABLE ACIDITY, NaOH with a Digital Titrator.............................. 137
SECTION 6 IRRIGATION WATER PROCEDURES .................................................... 141
ALKALINITY, Phenolphthalein and Total.......................................................................... 143
Using Sulfuric Acid with a Digital Titrator....................................................................... 143
CHLORIDE, Using Silver Nitrate with a Digital Titrator.................................................... 151
CONDUCTIVITY, Using Pocket Pal™ Conductivity Tester ............................................... 155
iv
TABLE OF CONTENTS, continued
HARDNESS, TOTAL, Using EDTA with a Digital Titrator ............................................... 159
NITRATE, HR, Cadmium Reduction Method...................................................................... 167
pH, Hach One® Combination pH Electode Method with a EC10 Portable Meter ................ 175
Sample pH Measurement ................................................................................................... 175
Two-Standard Calibration in Automatic Mode with Temperature Probe ......................... 175
PHOSPHORUS, REACTIVE,
(Also called Orthophosphate) PhosVer® 3 (Ascorbic Acid) Method ................................ 181
SULFATE, SulfaVer® 4 Method........................................................................................... 189
SECTION 7 SODIUM ESTIMATION AND
SODIUM ADSORPTION RATIO CALCULATIONS .................................................... 197
7.1 Na meq/L for Irrigation Water ........................................................................................ 197
7.1.1 Procedure .................................................................................................................. 197
7.1.2 Sample Calculations.................................................................................................. 197
GENERAL INFORMATION ........................................................................................ 199
HOW TO ORDER.............................................................................................................. 201
v
vi
PREFACE
This portable laboratory provides basic analyses for soil fertility assessment
and irrigation water quality when routine laboratory analysis is not convenient
or economical. This includes remote areas where facilities are not available or
in a classroom where an instructor wants to present the basics of soil analysis.
Prepackaged chemicals, simplified equipment and easy-to-follow procedures
make Hach methods easy and quick to use.
The DREL/2010 Soil and Irrigation Water Portable Laboratory was designed
to meet the needs of professional scientists and non-scientists alike. Every
possible effort was made to insure the results will be meaningful and
applicable. The data obtained should lead the analyst to interpretations that
correlate with interpretations from a competent full service soil laboratory.
The procedures in this manual were modified from the following books
and publications.
1. Handbook on Reference Methods For Soil Testing, Revised Edition -- 1980
The Council On Soil Testing and Plant Analysis
1111 Plant Science Building
Athens, Georgia
2. Recommended Chemical Soil Test Procedures for the North Central Region
Bulletin No. 499 (Revised)
North Central Regional Publication No. 221 (Revised)
North Dakota Agricultural Experiment Station
North Dakota State University
Fargo, North Dakota 58105
3. Diagnosis and Improvement of Saline and Alkali Soils
Agricultural Handbook No. 60
United Stated Department of Agriculture
Issued February 1954 (Out of Print)
Compiled by the United States Salinity Laboratory Staff
4. Methods of Soil Analysis, Part 2
American Society of Agronomy
Madison, Wisconsin -- 1965
5. Soil Testing and Plant Analysis, Third Edition
Soil Science Society of America, Inc.
Madison, Wisconsin -- 1991
6. Water Analysis Handbook, Second Edition
Hach Company
Loveland, Colorado -- 1992
vii
viii
SECTION 1
INTRODUCTION
1.1 Soil and Irrigation Water Manuals
The two manuals supplied with this kit acquaint users with Hach
procedures and techniques necessary for soil and irrigation water
characterization. The DREL/2010 Soil and Irrigation Water Procedures
Manual contains directions for performing the analyses.
The Hach Soil and Irrigation Water Interpretation Manual helps interpret
the results by providing basic information on soil fertility, soil
characterization, plant nutrition, fertilizer recommendation, and irrigation
water quality. This manual also contains a section on common conversion
factors used in soil and water analysis, a glossary of terms, reorder
information, and technical support information.
1.1.1 Using This Manual
This manual is arranged in sequential sections:
Section 1: aquaints the reader with some of the equipment and analytical
techniques used with the apparatus.
Section 2: details sampling and sample preparation for analysis.
Section 3: contains soil extraction procedures (see information below).
Section 4: contains soil analysis procedures in alphabetical order.
Section 5: details soil texture estimation.
Section 6: contains irrigation water analysis procedures.
1.1.2 Extracting Soil Samples
To analyze for a specific substance(s) in a soil, you often need to extract
that substance fromthe soil with a solvent (extractant). The analysis is
then completed on the solution containing the substance.
This manual contains all current Hach soil extraction procedures. The
following Extraction Guide outlines which extractions are used when
analyzing for the specific substances or parameters listed below each
extraction. It is important to use the indicated extraction. More than one
type of extraction for a given sample may be necessary.
The DREL/2010 portable laboratory does not include all Hach
extractants. Instead, a core system is provided with the capability to
customize the system, depending on the extraction procedures used.
1
INTRODUCTION, continued
The Mehlich 2 extract is included because:
1. Mehlich 2 is a viable choice for phosphorus extraction from most types of soils.
2. Other macronutrients (i.e., potassium, calcium, and magnesium) are
extracted with Mehlich 2, allowing for their measurement and
subsequent determination of cation exchange capacity and percent
base saturation in neutral to acidic soils.
1.1.3 Soil Extraction Guide
Determining the correct soil extract to use is based on the following criteria:
1. The geographical region of the soil.
2. The extracts used and recommended by local soil experts (usually
government agencies or universities). In the United States, local landgrant universities perform this function.
3. The physical and chemical properties of the soil.
The following matrix describes the extracts supplied by Hach and the
parameters for which the extracts are used.
Extractant
Parameter(s) Analyzed on Extract
Aqueous*
Salinity, pH
Calcium Sulfate*
Nitrate
Bray 1
Phosphorus (acid soils)
Bray 2
Phosphorus (acid soils)
Calcium Phosphate*
Sulfate
Calcium Sulfate, saturated*
Gypsum requirement, exchangeable
sodium
Mehlich 1
Calcium + Magnesium,
phosphorus, potassium
Mehlich 2*
Calcium + Magnesium,
phosphorus, potassium
Neutral normal Ammonium Acetate
Calcium + Magnesium,
sodium, potassium
Olsen
Phosphorus, Potassium
Potassium Chloride*
Total exchangeable acidity
Saturated Soil Paste
pH, soluble salts
SMP Buffer*
Lime requirement
* Indicates these supplies for the extraction are included in the DREL/2010 Soil and
Irrigation Water Portable Laboratory
2
INTRODUCTION, continued
Two methods for determining lime requirement are included in this
manual. The SMP buffer method is used for soils with lime
requirements above 2 tons/acre. However, when soils have a lime
requirement below 2 tons/acre or in tropical soils with high reserves
of aluminum, determining total exchangeable acidity should be
considered.
For screening purposes, soil salinity is determined with this kit using a
1:1 soil suspension instead of a saturated paste extract. However, where
salinity management and leaching requirements are of prime
importance, salinity should be determined using the traditional saturated
paste method. Hach Company provides a Soil Saturation Extract Kit
(Cat. No. 18700-00) to use with the Pocket Pal™ TDS Tester.
1.2 Using the Apparatus in the Kit
1.2.1 Accurately Measuring Liquids Using Eye Droppers and Graduated Cylinders
When small sample quantities are used, the accuracy of measurements is
important. Figure 1 illustrates the proper technique for reading the sample
level or the meniscus formed when the liquid wets the cylinder or wall of
the dropper.
Figure 1
Reading the Meniscus
50
45
40
35
1.2.2 Using the Soil Scoops
A set of soil scoops is included with the kit for sample measurement. The
set consists of three different sized scoops: 0.85 cc (1 g), 1.70 cc (2 g),
and 4.25 cc (5 g). In addition, a 0.2-g spoon is included for use in the
procedures. Use the following procedure when using the scoops:
1. Use a spatula to stir the soil sample.
3
INTRODUCTION, continued
2. Dip the scoop into the center of the soil sample to obtain a heaping
scoop full.
3. Hold the scoop firmly and tap the handle of the scoop sharply three
times with a spatula to settle the soil.
4. Hold the blade of the spatula perpendicular to the top of the scoop and
strike off the excess soil.
5. Empty the soil into the appropriate container for a given procedure.
1.2.2.1 Alternative Procedure
Use a balance instead of scoops to weigh the sample. Hach offers two
balances for soil testing. The AccuLab PocketPro 150 B is a top-loading
balance with readability of 0.1 g. For higher accuracy, a pan balance
(Ohaus) with readability to 0.01 g also is available.
4
SECTION 2
2.1
SAMPLE COLLECTION AND PREPARATION
Soil Preparation
2.1.1 Sampling, Drying, Grinding and Screening
The following method is commonly used to prepare soil samples for
subsequent testing. It applies to all classes of soils. The procedure is based
on the Recommended Chemical Soil Test Procedures for the North Central
Region, Bulletin No. 499 (Revised), October, 1980 published by The North
Dakota Agricultural Experiment Station, North Dakota State University.
2.1.2 Soil Sampling
For meaningful results, it is of utmost importance that the soil sample be
representative of the area being tested. Depending on the size of the
sampling area, take 15 to 20 subsamples from the area being sampled and
mix them together in a clean container. Use a sample of this mixture during
analysis to represent the area being tested. Subsamples (which should be
approximately the same size) may be obtained with a coring tube, soil auger
or shovel. Avoid sampling very unusual areas such as old manure piles, lime
piles, fence lines, etc. REMEMBER: The test results can no better represent
the testing area than does the soil sample from that area. The most valid
information regarding sampling can be obtained from the local extension
office, university or government agricultural department.
Sample preparation consists of drying, crushing, mixing and sieving.
These steps assure that a correct, representative sample is analyzed. Dry
the sample as outlined below.
1. Break up the large
2. Use a short board or
chunks of soil and spread
it out to air dry. Avoid
contamination by fertilizer
dusts or other such sources
of contamination. If a
forced-draft oven or
similar drying device is
used, set the heat no higher
than
60 °C (140 °F).
similar device to crush
the air dried soil.
3. Pass the crushed soil
through the 10-mesh
(2 mm) soil sieve
assembly included with
Note: A soil crusher may be
used in the laboratory (Cat. the kit.
No. 22520-00) to grind and
screen the soil.
4. Store the soil in a
cool, dry place until
the analysis is complete.
Rinse the spatula
with demineralized
water before stirring
each sample.
Note: Store the sample,
because it may be
necessary to re-test.
Note: A mortar and pestle
(included in the DREL/2010)
may also be used. Take care
to avoid grinding rocks.
5
SAMPLE COLLECTION AND PREPARATION, continued
2.1.3 Filtering Soil Extracts
Prepare a filter for filtration as follows:
1. Fold a sheet of filter paper by creasing it in half and then in half again.
Separate one edge from the other three to form a cone. Place the folded
paper in the funnel. See Figure 2.
Figure 2
Folding the Filter Paper
2. Open the filter in a manner that forms an inverted cone. Check the
filter paper for holes or tears — they can make the results inaccurate.
3. Rinse the funnel with demineralized water. Shake the funnel to remove
excess water.
4. Place the filter paper in the funnel.
5. Place the funnel into a round sample bottle or plastic cup to collect the extract.
Prefolded filter paper, sized for the filtration apparatus listed below, is
available in packs of 500 (Cat. No. 22633-56).
2.1.4 Using Additional Apparatus
Multiple Filtration Assembly
A filtration apparatus (Cat. No. 22624-00) is available for filtering soil
extracts. The apparatus includes a ten-place funnel stand, funnels and a
cup holder to receive the filtrate. See Figure 3.
6
SAMPLE COLLECTION AND PREPARATION, continued
Figure 3
Multiple Filtration Assembly
Soil Shaker
A soil shaker (Cat No. 22623-00) is a convenient way to extract large
numbers of samples and perform extended shaking times. The shaker has
two speeds. The low speed shakes at about 180 reciprocations per minute,
ideal for soil extraction. The shaker has a timer and may be used with
disposable plastic cups (Cat. No. 22631-74) and lids (Cat. No. 22632-74).
Additional shaking trays (Cat. No. 43399-00) and cup racks (Cat. No.
43402-00) are available. See Figure 4.
Figure 4
Soil Shaker
Digital Dispensers
Wheaton Variable Volume Digital Dispensers are available in 3 sizes:
• 0.5-5.9 mL (Cat. No. 25631-37)
• 1.0-10.9 mL (Cat. No. 25631-40)
• 5-59 mL (Cat. No. 25631-41)
7
SAMPLE COLLECTION AND PREPARATION, continued
These dispensers are accurate and convenient for dispensing precise
volumes of extracts or dilution water. They come with variable neck
adaptors to fit a wide variety of containers. Procedures for set-up, use, and
maintenance are provided with the dispenser.
Pour-out Dispensers
Hach fixed volume dispensers pour out volumes of 5.0 and 10 mL and are
convenient to use for extracting solutions. They are less expensive than
the variable volume dispensers, but less adaptable for laboratory use.
Soil Grinder
The Dynacrush Soil Crusher (Cat. No. 22520-00) significantly speeds
soil preparation by crushing and sieving air-dried soil samples in less
than 1 minute. See Figure 5.
Figure 5
Soil Grinder
Pour-Thru Cell
Hach provides a Pour-Thru Cell for the DR/2010 Spectrophotometer
(Cat. No. 45215-00). The cell replaces the matched sample cells and
provides constant optical characteristics for improved test precision; it
also decreases the time spent when multiple samples are analyzed.
See Figure 6.
8
SAMPLE COLLECTION AND PREPARATION, continued
Figure 6
Pour-Thru Cell
Disposable Cups and Lids
These cups (Cat. No. 22631-74) and lids (Cat. No. 22632-74) reduce the time
spent cleaning labware. Most soil procedures in this manual can be adapted to
their use. The shaking apparatus and filtration assembly have been designed to
use them.
ADDITIONAL APPARATUS LIST
Description
Unit
Cat. No.
AccuLab Pocket Pro 150 B Balance ..............................................................each .......25568-00
Ohaus Pan Balance.........................................................................................each .......18475-00
Soil Crusher 120/240V...................................................................................each .......22520-00
Soil Shaker 115V ...........................................................................................each .......22623-00
Soil Shaker 230V ...........................................................................................each .......22623-02
Digital Dispenser, 0.5-5.9 mL ........................................................................each .......25631-37
Digital Dispenser, 1.0-10.9 mL ......................................................................each .......25631-40
Digital Dispenser, 5-59 mL ............................................................................each .......25631-41
Pour-out Dispenser, 5 mL...............................................................................each .......22200-37
Pour-out Dispenser, 10 mL.............................................................................each .......22200-38
Pour-Thru Cell, DR/2010 ...............................................................................each .......45215-00
Filtration Apparatus Assembly.......................................................................each .......22624-00
Filter Paper, prefolded, for 22624-00 ......................................................500/pkg .......22633-56
Disposable Cups, 150 mL ......................................................................2500/pkg .......22631-74
Disposable Lids, for cups ......................................................................3000/pkg .......22632-74
9
SAMPLE COLLECTION AND PREPARATION, continued
2.1.5 Example of Procedure Using Alternative Apparatus
The following example for analyzing phosphorus uses the alternative
apparatus mentioned above and a different soil extractant than offered
with the DREL/2010 Spectrophotometer. In this example, the following
changes were made:
• Different extract
• Different soil:extract ratio
• Use of Soil Grinder
• Use of Multiple Filtration Apparatus
• Use of Digital Dispensers
• Use of Pour-Through Cell
Choose
Extractant
2. Use disposable cups
SOIL PREPARATION
SOIL EXTRACTION
1. Grind and sieve the
1. Choose appropriate instead of plastic vials
extractant (e.g., Bray 1). (especially for large
numbers of samples).
samples with a
mechanical grinder.
4. Use soil scoops to
measure soil
(e.g. 2 grams)
into cup.
5. Set dispenser to
3. Use a digital
dispenser instead of a
graduated cylinder.
6. Cover cups and shake 7. Filter extracts using
desired volume (20 mL for 5 minutes.
Filtration Assembly
of extract per cup).
Add extract to the
cup containing the
soil sample.
10
SAMPLE COLLECTION AND PREPARATION, continued
Determination of Phosphorus
3:00 minutes
1. Add 1 mL of filtered
2. Add one PhosVer® 3
extract to clean cup, then Powder Pillow and mix
add 24 mL demineralized well. Swirl to dissolve
water (25 mL total). Swirl the powder.
to mix.
3. Wait 3 minutes for
4. Rinse Pour-Thru Cell
color development.
with demineralized water,
then zero
the instrument.
5. Pour reacted samples 6. Multiply readings by
into Pour-Thru Cell.
the dilution factor to
obtain ppm P in soil.
2.2
Determining the Dilution Factor
Use this formula to determine actual ppm in soil:
ppm soil basis =
Instrument reading × Vol. extractant (mL) × Final analysis vol. (mL)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Sample weight (g) × Aliquot vol. of extract (mL)
In the above procedure, the following numbers would be used in the equation.
Apparent Value = 0.46 ppm
Volume extractant = 20 mL
Final analysis volume = 25 mL
Sample weight = 2 g
Aliquot volume of extract = 1 mL
0.46 × 20 mL × 25 mL
115 ppm in soil = --------------------------------------------------------2 g × 1 mL
11
SAMPLE COLLECTION AND PREPARATION, continued
2.3
Conversion from ppm to lbs/acre or kg/ha
The following formula assumes a sample bulk density of 1.2 g/cm3 and
uses a 0.3 constant to reflect the assumption
lbs/acre = ppm soil basis × 0.3 × inches of sample depth
For the example above, assume the soil was sampled to a depth of 6
inches (15.24 cm). So:
115 × 0.3 × 6 in. = 207 lbs/acre phosphorus
To convert from ppm to kg/ha, the formula is:
kg/ha = ppm soil basis × 0.1344 × cm of sample depth
For the above sample with a 15.25 cm sample depth, the conversion is:
115 × 0.1344 × 15.24 cm = 235 kg/ha
2.4
Extraction Guide
This guide is a quick reference to Hach’s soil analysis products. It will aid the
analyst in customizing the DREL/2010 Portable Laboratory or building a soil
testing laboratory. The program numbers listed assume the DR/2010
Spectrophotometer is used. If the same soil:extractant ratio and sample
dilution is used, the multiplier will be the same for all Hach
spectrophotometer instruments. Any Hach colorimeter or spectrophotometric
may be used with the appropriate water calibration curve.
.
Table 1 Spectrophometric Methods Using Water Calibration Curves
Parameter
Extraction
Nitrate
Calcium Sulfate
Organic Matter Potassium Dichromate
Phosphorus
Bray 1
Phosphorus
Bray 2
Phosphorus
Mehlich 1
Phosphorus
Mehlich 2 SIW*
Phosphorus
Olsen
Phosphorus
Mehlich 2
Potassium
Ammonium Acetate
Potassium
Mehlich 1
Potassium
Mehlich 2
Potassium
Mehlich 2 SIW*
Potassium
Olsen
Ca + Mg
Ammonium Acetate
Ca + Mg
Mehlich 1
Ca + Mg
Mehlich 2
Ca + Mg
Mehlich 2 SIW*
Sulfur (sulfate)
Calcium Phosphate
Ratio
Dilution
Program
Multiplier
Unit
1:2
1:10
1:10
1:10
1:5
1:10
1:20
1:8.5
1:5
1:5
1:8.5
1:10
1:20
1:5
1:5
1:8.5
1:10
1:2
direct
direct
1:25
1:25
1:25
1:25
3:25
1:25
3:25
3:25
3:25
3:25
3:25
0.2:100
0.2:100
0.2:100
0.2:100
direct
355
420
490
490
490
490
490
491
user entered
user entered
user entered
user entered
user entered
220,225
221,226
221,226
221,226
680
2
1
250
250
125
250
167
212.5
41.67
41.67
70.8
83.3
167
2500
2500
4250
5000
2
ppm soil basis
% soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
ppm soil basis
*The Mehlich 2 SIW uses a different extraction ratio for easy application in the field.
12
SAMPLE COLLECTION AND PREPARATION, continued
Table 2 Ion Selective Electrode
Parameter
Extraction
Ratio
Dilution
Program
Multiplier
Unit
Lime Rqmt.
Lime Rqmt. Pillow
8:21
direct
——
1
Tons/acre
Multiplier
Unit
Table 3 Titrimetric Methods
Parameter
Extraction
Ratio
Dilution
Cartridge
Ca + Mg
Ammonium Acetate
1:5
1 mL
0.08 M EDTA digits ÷ 10
meq/100 g
Ca + Mg
Mehlich 1
1:5
1 mL
0.08 M EDTA digits ÷ 10
meq/100 g
Ca + Mg
Mehlich 2
1:8.5
1 mL
0.08 M EDTA
digits ÷
5.88
meq/100 g
Ca + Mg
Mehlich 2 SIW
1:10
2 mL
0.08 M EDTA
digits ÷ 5
meq/100 g
Sodium
Calcium Sulfate
1:20
1 mL
0.8 M EDTA
Calculated from
Gypsum
Rqmt.
meq/100 g
Sulfur Rqmt.
Water
10 g
sample
8.0 N H2SO4
digits x 64
meq/100 g
Gypsum Rqmt.
Calcium Sulfate
1:20
1 mL
0.8 M EDTA
——
Tons/acre
Total
Exchangeable
Acidity
Potassium chloride
5g
50 mL
1.6 N NaOH
digits ÷ 25
meq/100 g
2.5
Obtaining Water Samples
• The minimum volume of water recommended for analysis is
approximately 1 liter. Take care to obtain a representative sample.
Satisfactory samples of some waters can be obtained only by mixing
several portions collected at different times. Collection and mixing
technique depend on local conditions.
• Samples from wells should be collected after the pump has run for
10 minutes.
• Samples from streams should be taken from running water.
• The most valid information regarding sampling can be obtained from
the local extension office
• In general, the shorter the elapsed time between collection and
analysis of a sample, the more reliable the analytical data will be.
Changes resulting from chemical and biological activity may alter the
composition of the sample.
13
SAMPLE COLLECTION AND PREPARATION, continued
Use the following procedure to obtain a water sample:
1. Rinse the sample container 3 times with the water to be analyzed.
2. Fill the container completely full with the water to be analyzed and
cap tightly.
3. Analyze the sample as soon as possible.
14
SECTION 3
SOIL EXTRACTION PROCEDURES
15
16
AQUEOUS EXTRACTION (1:1 or 1:2)
Method 10087
For Soil Extraction
Used for Salinity and pH
1. Dry the soil sample.
2. Using a 5-gram
Screen it to a fineness of scoop, measure 4 scoops
0-2 mm with the Hach
of prepared soil into a
Soil Sieve.
120-mL
snap-top container.
Note: Careful preparation
is important to assure
volumetric measurement
of the sample. See the
introductory sections for
soil sampling and
sample preparation.
Note: Steps 2 and 3 make a
1:1 water/soil suspension. To
make a 1:2 suspension, add
40 mL (instead of 20 mL) of
demineralized water to a
120-mL snap-top container.
3. Using a 25-mL
4. Shake the contents of
graduated cylinder,
accurately measure
20 mL of demineralized
water into the 120-mL
snap-top container.
the container for 1 minute
at 10-minute intervals for a
30-minute period.
Note: To prevent confusion
when working with several
samples, label each snap-top
container with the sample or
test name.
Note: A balance may be
used to weigh 20 g of soil.
30:00 minutes
5. After 30 minutes,
use the prepared
sample for salinity and
pH determination.
Note: Because conductivity
is affected by minute
amounts of potassium
chloride resulting from pH
determination, measure the
salinity of the sample before
measuring the pH.
17
Note: Rinse the spatula with
demineralized water before
stirring each sample.
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
Shaking time is 30 minutes.
AQUEOUS EXTRACTION, continued
Summary of Method
Use the Aqueous Extraction method to prepare soil for salinity and pH
measurements. This method applies to all classes of soil. Filtering the soil
suspension is not necessary to determine pH or salinity; measurements are
made directly in the suspension.
REQUIRED REAGENTS AND APPARATUS
Quantity Required
Per Test
Description
Unit
Cat. No.
Cylinder, graduated, 25 mL .................................................1 ....................... each......... 2172-40
Soil Sieve .............................................................................1 ....................... each....... 46159-00
Scoop, 5-gram......................................................................1 ....................... each....... 26572-05
Spatula, stainless steel..........................................................1 ....................... each........... 561-62
Snap-top Container, 120 mL................................................1 ....................... each....... 25522-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each....... 25568-00
Weighing Paper ........................................................................................ 500/pkg....... 14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
18
BRAY P1 (WEAK) EXTRACTION
Method 10088
For Soil Extraction
Used for Phosphorus in Acid Soils
Preparing the Bray P1 Extractant
Bray P1
1. Measure 20 mL of the 2. Transfer the
Bray P1 Soil Extractant
extractant concentrate to
Concentrate into a 25-mL one of the 200-mL flipgraduated cylinder.
top dispensing bottles
provided.
3. Add demineralized
water to the dispensing
bottle until the volume
reaches the bottom of
the neck. Invert several
times to mix.
4. Label the bottle with
the extractant name and
date prepared to avoid
confusion when working
with several extractants.
Note: Do not use
undiluted concentrate; it
must be diluted 1:10
before use.
Extracting the Soil
2. With a 2-g (1.70 cc)
Screen it to a fineness of soil scoop, add one scoop
0-2 mm with the Hach
of soil to a 120-mL snapSoil Sieve.
top container.
1. Dry the soil sample.
Note: Careful preparation
is important to assure
volumetric measurement of
the sample. See the
introductory sections for
soil sampling and
sample preparation.
3. Using a 25-mL
graduated cylinder,
accurately measure
20 mL of the prepared
Bray P1 Soil Extractant
Note: A balance may be
used to weigh 2.0 g of soil. into the container.
19
4. Close the lid and
shake the contents of the
container for 5 minutes
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
BRAY P1 (WEAK) EXTRACTION, continued
5. Using a plastic funnel
and filter paper, filter the
extracted sample into
another 120-mL snap-top
container. Save the filtered
liquid (filtrate) for
analysis. Limit filtration
time to 10-minutes.
The filtrate is stable for
about 12 hours.
Note: The Filtration
Assembly can be used for
multiple samples.
Sampling and Storage
The diluted Bray P1 extract solution is stable for about 12 months. Protect
the extractant from evaporation and contamination.
Summary of Method
The Bray P1 Soil Extractant is widely used for extracting phosphorus
from acid soil. Hydrogen ions (H+) in the extractant make phosphorus
more soluble. The method also uses fluoride (F-) to lower the activity of
aluminum (Al3+), calcium (Ca2+) and iron (Fe3+) in the extraction system.
Clay soils with a moderately high degree of base saturation decrease the
ability of the extract to dissolve phosphorus.
Normally, this method should be limited to soils with a pH of less than 6.8
when the texture is silty clay or finer. With calcareous soils or at higher
pH levels, fine-textured soils may be tested, but they require higher ratios
of extractant to soil. This method is also suited for organic soils.
Bray P1 values are often used in association with Bray P2 values to determine
readily-available phosphorus vs. reservoir (labile) phosphorus. Bray P2 is a
stronger acid and usually gives a higher phosphorus result because it extracts
the reservoir phosphorus. As the Bray P2:Bray P1 ratio approaches 1, the
20
BRAY P1 (WEAK) EXTRACTION, continued
phosphorus reservoir is being depleted and the amount of phosphorus added
can be effectively managed. The procedure is based on the Handbook on
Reference Methods for Soil Testing, 1980 edition, published by the Council
for Soil Testing and Plant Analysis.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Bray P1 Soil Extractant Concentrate........................ 20 mL/10 tests ...............1 L .......22661-53
REQUIRED APPARATUS
Bottle, poly, 200 mL............................................................ 1....................... each .........5909-00
Cap, 3-piece, w/ screen ....................................................... 1........................each .........5912-00
Cylinder, graduated, poly, 25 mL........................................ 1........................each .........2172-40
Filter Paper, circular, 15 mm ............................................... 1..................100/pkg ...........506-58
Funnel, poly, 82 mm............................................................ 1........................each .......24155-82
Snap-top Container, 120 mL ............................................... 1........................each .......25522-00
Soil Scoop, 2 g .................................................................... 1........................each .......26572-02
Soil Sieve............................................................................. 1........................each .......46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ..............................................................each .......25568-00
Disposable Cups.....................................................................................2500/pkg .......22631-74
Disposable Lids, for cups .......................................................................3000/pkg .......22632-74
Filtration Assembly w/ 10 funnels,
cup rack and funnel rack .............................................................................each .......22624-00
Filter Paper, for Filtration Assembly, pre-folded .....................................500/pkg .......22633-56
Shaker Assembly, includes 4 sample racks,
2-speed shaker, time switch, and shaker plate, 115V .................................each .......22623-00
Shaker Assembly, includes 4 sample racks,
2-speed shaker, time switch, and shaker plate, 230V .................................each .......22623-02
Weighing Paper ........................................................................................500/pkg .......14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
21
22
BRAY P2 (STRONG) EXTRACTION
Method 10089
For Soil Extraction
Used for Phosphorus in Acid Soils
Preparing the Bray P2 Extractant
Bray P2
1. Measure 20 mL
2. Transfer the
of the Bray P2 Soil
Extractant Concentrate
into a 25-mL
graduated cylinder.
extractant concentrate to
one of the 200-mL fliptop dispensing bottles
provided.
3. Add demineralized
water to the dispensing
bottle until the volume
reaches the bottom of
the neck. Invert several
times to mix.
4. Label the bottle with
the extractant name and
date prepared to avoid
confusion when working
with several extractants.
Note: Do not use undiluted
concentrate; it must be
diluted 1:10 before use.
Extracting the Soil
2. With a 2-g (1.70 cc)
Screen it to a fineness of soil scoop, add one scoop
0-2 mm with the Hach
of soil to a 120-mL snapSoil Sieve.
top container.
1. Dry the soil sample.
Note: Careful preparation
is important to assure
volumetric measurement
of the sample. See the
introductory sections
for soil sampling and
sample preparation.
3. Using a 25-mL
graduated cylinder,
accurately measure
20 mL of the prepared
Bray P2 Soil Extractant
Note: A balance may be
used to weigh 2.0 g of soil. into the container.
23
4. Close the lid and
shake the contents of
the container for
5 minutes
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
BRAY P2 (STRONG) EXTRACTION, continued
5. Using a plastic funnel
and filter paper, filter the
extracted sample into
another 120-mL snap-top
container. Save the filtered
liquid (filtrate) for
analysis. Limit filtration
time to 10 minutes. The
filtrate is stable for about
12 hours.
Note: The Filtration
Assembly can be used for
multiple samples.
Sampling and Storage
The diluted Bray P2 extract solution is stable for about 12 months. Protect
the extractant from evaporation and contamination.
Summary of Method
The Bray P2 Soil Extractant is widely used for extracting phosphorus
from acid soil. Hydrogen ions (H+) in the extractant make phosphorus
more soluble. The method also uses fluoride (F-) to lower the activity of
aluminum (Al3+), calcium (Ca2+) and iron (Fe3+) in the extraction system.
Clay soils with a moderately high degree of base saturation decrease the
ability of the extract to dissolve phosphorus.
Normally, this method should be limited to soils with a pH of less than 6.8
when the texture is silty clay or finer. With calcareous soils or at higher
pH levels, fine-textured soils may be tested, but they require higher ratios
of extractant to soil. This method is also suited for organic soils.
Bray P2 values are often used in association with Bray P1 values to
determine readily available phosphorus vs. reservoir (labile) phosphorus.
Bray P2 is a stronger acid and usually gives a higher phosphorus result
because it extracts the reservoir phosphorus. As the Bray P2:Bray P1 ratio
24
BRAY P2 (STRONG) EXTRACTION, continued
approaches 1, the phosphorus reservoir is being depleted and the amount of
phosphorus added can be effectively managed. The procedure is based on
the Handbook on Reference Methods for Soil Testing, 1980 edition,
published by the Council for Soil Testing and Plant Analysis.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Bray P2 Soil Extractant Concentrate........................ 20 mL/10 tests ...............1 L .......23632-53
REQUIRED APPARATUS
Bottle, poly, 200 mL............................................................ 1....................... each .........5909-00
Cap, 3-piece, w/ screen ....................................................... 1........................each .........5912-00
Cylinder, graduated, poly, 25 mL........................................ 1........................each .........2172-40
Filter Paper, circular, 15 mm ............................................... 1..................100/pkg ...........506-58
Funnel, poly, 82 mm............................................................ 1........................each .......24155-82
Snap-top Container, 120 mL ............................................... 1........................each .......25522-00
Soil Scoop, 2 g .................................................................... 1........................each .......26572-02
Soil Sieve............................................................................. 1........................each .......46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ..............................................................each .......25568-00
Disposable Cups.....................................................................................2500/pkg .......22631-74
Disposable Lids, for cups .......................................................................3000/pkg .......22632-74
Filtration Assembly w/ 10 funnels,
cup rack and funnel rack .............................................................................each .......22624-00
Filter Paper, for Filtration Assembly, pre-folded .....................................500/pkg .......22633-56
Shaker Assembly, includes 4 sample racks,
2-speed shaker, time switch, and shaker plate, 115V .................................each .......22623-00
Shaker Assembly, includes 4 sample racks,
2-speed shaker, time switch, and shaker plate, 230V .................................each .......22623-02
Weighing Paper ........................................................................................500/pkg .......14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
25
26
CALCIUM PHOSPHATE SOIL EXTRACTION
Method 10090
For Soil Extraction
Used for Sulfate
1. Dry the soil sample.
2. Using a 5-g scoop
Screen it to a fineness of (4.25 cc), measure
0-2 mm with the Hach
5 scoops of prepared
Soil Sieve.
soil into a 120-mL
snap-top container.
3. Add 50 mL of
4. Add the contents of
demineralized water to
the container.
one Sulfate Extractant 1
Powder Pillow. Close the
lid.
5. Shake the container
for 10 minutes.
6. Add one level 3.5-cc
7. Using a plastic funnel
scoop of activated
Charcoal Powder to the
container. Close the lid
and shake to mix.
and filter paper, filter the
extracted sample into
another 120-mL snap-top
container. Save the
filtered liquid (filtrate) for
analysis. The filtrate is
stable for about 4 hours.
Note: Careful preparation
is important to assure
Note: A balance may be used
volumetric measurement of to weigh 25grams of soil.
the sample. See the
introductory sections for
soil sampling and
sample preparation.
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
Note: The Filtration
Assembly can be used for
multiple samples.
27
CALCIUM PHOSPHATE SOIL EXTRACTION, continued
Summary of Method
Soluble sulfate, plus a fraction of the adsorbed sulfate, is extracted with a
solution of calcium phosphate (CaHPO4) provided by the extractant. The
phosphate ions displace the adsorbed sulfate, and the calcium ions inhibit
the extraction of organic matter, eliminating contamination from the
extractable organic sulfur. Activated charcoal is mixed with the extraction
solution before filtering to form a colorless, clear extract.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Sulfate Extractant Powder Pillows.......................................1 ................... 50/pkg....... 20577-96
Activated Charcoal Powder ............................................. 3.5 cc.................. 100 g....... 20526-26
REQUIRED APPARATUS
Cylinder, graduated, mixing, 50 mL ....................................1 ...................... each......... 1896-41
Filter Paper, circular, 15 mm................................................1 ................. 100/pkg........... 506-58
Funnel, poly, 82 mm ............................................................1 ...................... each....... 24155-82
Snap-top Container, 120 mL................................................1 ...................... each....... 25522-00
Scoopula, stainless steel.......................................................1 ...................... each....... 12257-00
Soil Scoop, 3.5 cc ................................................................1 ...................... each....... 17044-00
Soil Scoop, 5 g .....................................................................1 ...................... each....... 26572-05
Soil Sieve .............................................................................1 ...................... each....... 46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each....... 25568-00
Disposable Cups .................................................................................... 2500/pkg....... 22631-74
Disposable Lids, for cups....................................................................... 3000/pkg....... 22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack ....................... each....... 22624-00
Filter Paper, for Filtration Assembly, pre-folded ..................................... 500/pkg....... 22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V........................................................... each....... 22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V........................................................... each....... 22623-02
Weighing Paper ........................................................................................ 500/pkg....... 14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
28
CALCIUM SULFATE SOIL EXTRACTION
Method 10091
For Soil Extraction
Used for Nitrate
1. Dry the soil sample.
2. Using a 5-g scoop
Screen it to a fineness of (4.25 cc), measure
0-2 mm with the Hach
6 scoops of prepared
Soil Sieve.
soil into a 120-mL
snap-top container.
Note: Careful preparation
is important to assure
Note: A balance may be
volumetric measurement
used to weigh 30 grams
of the sample. See the
of soil.
introductory sections
for soil sampling and
sample preparation.
3. Using a 0.2-gram
4. Using a 50-mL
plastic spoon, add 2 level
spoonfuls of the calcium
sulfate powder to the
container.
graduated cylinder,
accurately measure
60 mL of demineralized
water and transfer it to
the snap-top container.
Note: A balance may be
used to weigh 0.4 of
calcium sulfate.
5. Close the lid and
6. Using a plastic funnel
shake the container
and filter paper, filter the
vigorously for 1 minute. extracted sample into
another 120-mL
Note: The Soil Shaker
snap-top vial. Save the
(22623-00 or 22623-02)
filtered liquid (filtrate)
and plastic cups can be
used for multiple samples. for analysis. The filtrate
is stable for about
2 hours.
Note: The Filtration
Assembly may be used for
multiple samples.
29
CALCIUM SULFATE SOIL EXTRACTION, continued
Summary of Method
The Calcium Sulfate Extraction is essentially an aqueous extraction; the
calcium sulfate aids in the filtration step. It is widely used for extracting
nitrate-nitrogen from soils and can be used for all classes of soil. The
procedure is based on the Recommended Chemical Soil Test Procedures
for the North Central Region, Bulletin No. 499 (revised), October 1980,
published by the North Dakota Agricultural Experiment Station, North
Dakota State University.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Calcium Sulfate Powder ...................................................0.4 g .................... 20 g....... 12321-20
REQUIRED APPARATUS
Cylinder, graduated, mixing, 50 mL ....................................1 ...................... each......... 1896-41
Filter Paper, circular, 15 mm................................................1 ................. 100/pkg........... 506-58
Funnel, poly, 82 mm ............................................................1 ...................... each....... 24155-82
Measuring Spoon, 0.2 g .......................................................1 ....................... each........... 638-00
Snap-top Container, 120 mL................................................1 ...................... each....... 25522-00
Soil Scoop, 5 g .....................................................................1 ...................... each....... 26572-05
Soil Sieve .............................................................................1 ...................... each....... 46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................. each....... 25568-00
Disposable Cups .................................................................................... 2500/pkg....... 22631-74
Disposable Lids, for cups....................................................................... 3000/pkg....... 22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack ....................... each....... 22624-00
Filter Paper, for Filtration Assembly, pre-folded ..................................... 500/pkg....... 22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V........................................................... each....... 22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 230V........................................................... each....... 22623-02
Weighing Paper ........................................................................................ 500/pkg....... 14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
30
SATURATED CALCIUM SULFATE EXTRACTION
Method 10092
For Soil Extraction
Used for Gypsum Requirement and Exchangeable Sodium
Preparing the Extractant
1. Using the 1-gram soil
2. Add demineralized
scoop, add one level scoop water until the volume
of calcium sulfate to a flip- reaches the bottom of
top dispensing bottle.
the neck.
3. Shake the dispensing
bottle vigorously several
times over a
30-minute period to
dissolve the calcium
sulfate (a small amount
may not dissolve).
Note: Lable the bottle with
the extractant name when
working with other
extractants.
Extracting the Soil
1:00 minute
1. Dry the soil sample.
2. Using the 5-gram soil
Screen it to a fineness of scoop, add one scoop of
0-2 mm with the Hach
the soil into a 120-mL
Soil Sieve.
snap-top container.
Note: Careful preparation
is important to assure
volumetric measurement
of the sample. See the
introductory sections for
soil sampling and
sample preparation.
3. Using a 25-mL
graduated cylinder,
accurately measure
100 mL of the saturated
sulfate solution and
Note: A balance may be used
transfer it to the
to weigh 5 grams of soil.
snap-top container.
31
4. Close the lid. Shake
the container for
1 minute at 10-minute
intervals over a
30-minute period.
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
SATURATED CALCIUM SULFATE EXTRACTION , continued
5. Using a plastic
funnel and filter paper,
filter the extracted
sample into another
120-mL snap-top
container. Use the
filtered extract to
determine gypsum
requirement and
exchangeable sodium.
Note: The Filtration
Assembly can be used for
multiple samples.
Summary of Method
This method is used to determine gypsum requirement and, by
calculation, can estimate the meq/100 g of exchangeable sodium in the
sample. The procedure is based on the principle that the calcium ions in
the saturated solution of calcium sulfate will replace the exchangeable
sodium in the soil. The number of milliequivalents of sodium displaced
equals the number of Ca2+ milliequivalents extracted from the saturated
calcium sulfate solution.
32
SATURATED CALCIUM SULFATE EXTRACTION , continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Calcium Sulfate Power ................................................. 1g/10 test ................. 20 g .......12321-20
REQUIRED APPARATUS
Cylinder, graduated,25 mL, poly......................................... 1....................... each .........2172-40
Filter Paper, circular, 15 mm ............................................... 1..................100/pkg ...........506-58
Funnel, poly, 82 mm............................................................ 1....................... each .......24155-82
Measuring Spoon, 0.2 g....................................................... 1........................each ...........638-00
Snap-top Container, 120 mL ............................................... 1....................... each .......25522-00
Scoopula, stainless steel ...................................................... 1....................... each .......12257-00
Soil Scoop, 1g ..................................................................... 1....................... each .......26572-01
Soil Sieve............................................................................. 1....................... each .......46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each .......25568-00
Disposable Cups.....................................................................................2500/pkg .......22631-74
Disposable Lids, for cups .......................................................................3000/pkg .......22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack........................each .......22624-00
Filter Paper, for Filtration Assembly, pre-folded .....................................500/pkg .......22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V ...........................................................each .......22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 230V ...........................................................each .......22623-02
Weighing Paper ........................................................................................500/pkg .......14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
33
34
Method 10093
For Soil Extraction
MEHLICH 1 EXTRACTION
Used for Calcium and Magnesium, Phosphorus, Potassium and Sodium
Preparing the Mehlich 1 Extractant
MEHLICH 1
1. Measure 20 mL of the 2. Transfer the extractant
3. Add demineralized
4. Label the bottle with
Mehlich 1 Soil Extractant concentrate to one of the
Concentrate into a 25-mL flip-top dispensing
graduated cylinder.
bottles provided.
water to the dispensing
bottle until the volume
reaches the bottom of
the neck. Invert several
times to mix.
the extractant name to
avoid confusion when
working with other
extractants. The Mehlich 1
Soil Extractant is now
ready for use.
Preparing the Soil
5:00 minutes
1. Dry the soil sample.
2. Using a 5-g scoop,
Screen it to a fineness of measure one scoop
0-2 mm with the Hach
of prepared soil
Soil Sieve.
into a 120-mL
snap-top container.
3. Using a 25-mL
graduated cylinder,
accurately measure
25 mL of the diluted
Mehlich 1 Soil Extractant
Note: Careful preparation is
important to assure volumetric Note: A balance may be used into the cylinder, then
transfer it to the
measurement of the sample.
to weigh 5 grams of soil.
snap-top container.
See the introductory sections
for soil sampling and
sample preparation.
35
4. Close the lid. Shake
the container for
5 minutes.
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
MEHLICH 1 EXTRACTION, continued
5. Using a plastic funnel 6. Use this filtered
and filter paper, filter
the extracted sample
into another 120-mL
snap-top container.
extract for calcium and
magnesium, phosphorus
and potassium analysis.
Note: The Filtration
Assembly can be used for
multiple samples.
Note: The filtered Mehlich 1
soil extract is stable for
approximately 24 hours.
Sampling and Storage
The filtered Mehlich 1 soil extract is stable for approximately 24 hours. If
stored longer, refrigerate to prevent microbial growth.
Summary of Method
Also called the Double Acid Extraction, this method is used primarily to
determine phosphorus, potassium, calcium, magnesium and sodium in soils
with exchange capacities of less than 10 meq/100 g, are acid in reaction (pH
6.5), and are relatively low in organic matter content (5%). This method is not
suited for alkaline soils. The method is well suited for potassium
determination using an ion selective electrode. The procedure is based on the
Handbook on Reference Methods for Soil Testing, 1980 edition, published by
The Council on Soil Testing and Plant Analysis.
36
MEHLICH 1 EXTRACTION, continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Soil Extraction Concentrate, Mehlich 1 ..................... 20 mL/8 test.................1 L .......22662-53
REQUIRED APPARATUS
Bottle, polyethylene, 200 mL.............................................. 1........................each .........5909-00
Cap, 3-piece, w/screen ........................................................ 1........................each .........5912-00
Cylinder, graduated, polymethylpentene, 25mL ................. 1....................... each .........2172-40
Filter Paper, circular, 15 mm ............................................... 1..................100/pkg ...........506-58
Funnel, poly, 82 mm............................................................ 1....................... each .......24155-82
Snap-top Container, 120 mL ............................................... 1....................... each .......25522-00
Soil Scoop, 5 g .................................................................... 1....................... each .......26572-05
Soil Sieve............................................................................. 1....................... each .......46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each .......25568-00
Disposable Cups.....................................................................................2500/pkg .......22631-74
Disposable Lids, for cups .......................................................................3000/pkg .......22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack........................each .......22624-00
Filter Paper, for Filtration Assembly, pre-folded .....................................500/pkg .......22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V ...........................................................each .......22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 230V ...........................................................each .......22623-02
Weighing Paper ........................................................................................500/pkg .......14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
37
38
Method 10094
For Soil Extraction
MEHLICH 2 EXTRACTION
Used for Calcium and Magnesium, Phosphorus, Potassium and Sodium
Preparing the Mehlich 2 Extractant
MEHLICH 2
1. Measure 20 mL of the 2. Transfer the extractant 3. Add demineralized
4. Label the bottle with
Mehlich 2 Soil Extractant concentrate to one of the water to the dispensing
Concentrate into a 25-mL flip-top dispensing bottles bottle until the volume
graduated cylinder.
provided.
reaches the bottom of
the neck. Invert several
times to mix.
the extractant name to
avoid confusion when
working with other
extractants. The Mehlich
2 Soil Extractant is now
ready for use.
Preparing the Soil
5:00 minutes
1. Dry the soil sample.
2. Using a 2-g scoop,
Screen it to a fineness of measure one scoop
0-2 mm with the Hach
of prepared soil
Soil Sieve.
into a 120-mL
snap-top container.
Note: Careful
preparation is important
to assure volumetric
measurement of the
sample. See the
introductory sections
for soil sampling and
sample preparation.
Note: A balance may be
used to weigh 2 g of soil.
3. Using a 25-mL
4. Close the lid. Shake
graduated cylinder,
accurately measure
25 mL of the diluted
Mehlich 2 Soil Extractant
into the cylinder,
then transfer it to the
snap-top container. This
solution is referred to as
Mehlich 2 SIW.
the container for
5 minutes.
Note: Most Mehich 2
extractants are prepared using
17-mL of concentratate. The
DREL/2010 Portable
Laboratory uses 20-mL for
ease of use in the field.
39
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
MEHLICH 2 EXTRACTION, continued
5. Using a plastic funnel 6. Use this filtered
and filter paper, filter the
extracted sample into
another 120-mL
snap-top container.
Note: The Filtration
Assembly can be used for
multiple samples.
extract for calcium and
magnesium, phosphorus
and potassium analysis.
Note: The filtered Mehlich
2 soil extract is stable for
approximately 24 hours.
Sampling and Storage
The filtered Mehlich 2 soil extract is stable for approximately 24 hours. If
stored longer, refrigerate to prevent microbial growth.
Summary of Method
This method is used primarily for determining phosphorus, potassium,
calcium, magnesium and sodium in all soil types. With highly calcareous
soils, calcium and magnesium values will be artificially high. Because
ammonium is present in the composition of Mehlich 2, it is not suitable
for determination of potassium by ion selective electrode. This method is
highly correlated with Bray P1 and Olsen extractions over a wide range of
soil properties. It is also highly correlated with Mehlich 1 extraction in
neutral to acid soils where aluminum and iron forms of phosphorus
predominate. In comparison to the NNAA method using a 1:5
soil:extractant ratio and 5 minutes for extraction, Mehlich 2 extraction
was found to extract about 90 to 100% potassium, and 80 to 100%
calcium and magnesium. The procedure is based on the Handbook on
Reference Methods for Soil Testing, 1980 edition published by The
Council on Soil Testing and Plant Analysis.
40
MEHLICH 2 EXTRACTION , continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Soil Extraction Concentrate, Mehlich 2 .................... 20 mL/10 test........ 500 mL .......22663-49
REQUIRED APPARATUS
Bottle, polyethylene, 200 mL.............................................. 1........................each .........5909-00
Cap, 3-piece, w/screen ........................................................ 1........................each .........5912-00
Cylinder, graduated, polymethylpentene, 25mL ................. 1....................... each .........2172-40
Filter Paper, circular, 15 mm ............................................... 1..................100/pkg ...........506-58
Funnel, poly, 82 mm............................................................ 1....................... each .......24155-82
Snap-top Container, 120 mL ............................................... 1....................... each .......25522-00
Soil Scoop, 5 g .................................................................... 1....................... each .......26572-05
Soil Sieve............................................................................. 1....................... each .......46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each .......25568-00
Disposable Cups.....................................................................................2500/pkg .......22631-74
Disposable Lids, for cups .......................................................................3000/pkg .......22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack........................each .......22624-00
Filter Paper, for Filtration Assembly, pre-folded .....................................500/pkg .......22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V ...........................................................each .......22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 230V ...........................................................each .......22623-02
Weighing Paper ........................................................................................500/pkg .......14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
41
42
Method 10095
NEUTRAL NORMAL AMMONIUM ACETATE EXTRACTION
Used for Calcium and Magnesium, Potassium and Sodium
For Soil Extraction
Preparing the NNAA Extractant
NNAA
1. Measure 40-mL of the 2. Transfer the extractant
3. Add demineralized
4. Label the bottle with
Ammonium Acetate Soil concentrate to one of
Extractant Concentrate
the flip-top dispensing
into a 50-mL graduated
bottles provided.
cylinder.
water to the dispensing
bottle until the volume
reaches the bottom of
the neck. Invert several
times to mix.
the extractant name to
avoid confusion when
working with other
extractants. The Neutral
Normal Ammonium
Acetate (NNAA) Soil
Extractant is stable for
approximately 6 months.
Protect from evaporation
and contamination.
Note: Do not use undiluted
concentrate; it must be
diluted before use (1 part
concentrate to 4 parts
demineralized water).
Preparing the Soil
5:00 minutes
1. Dry the soil sample.
2. Using a 5-gram
Screen it to a fineness of scoop (4.25 cc),
0-2 mm with the Hach
measure one scoopful
Soil Sieve.
of prepared soil into a
120-mL snap-top
Note: Careful preparation is
important to assure volumetric container.
3. Add 25.0 mL of
4. Close the lid. Shake
Neutral Normal
the container for
Ammonium Acetate Soil 5 minutes.
Extractant to the container.
measurement of the
Note: A balance may be used
sample. See the introductory to weigh 5 grams of soil.
sections for soil sampling and
sample preparation.
43
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
NEUTRAL NORMAL AMMONIUM ACETATE EXTRACTION, continued
5. Using a plastic funnel
and filter paper, filter the
extracted sample into
another 120-mL snap-top
container. Save the filtrate
(extract) for analysis.
Note: The Filtration
Assembly can be used for
multiple samples.
Sampling and Storage
The diluted Neutral Normal Ammonium Acetate (NNAA) extract solution is
stable for approximately 6 months. Protect from evaporation and
contamination. The soil filtrate (extract) is stable for approximately 24 hours.
If stored longer, either refrigerate or treat to prevent microbial growth.
Summary of Method
NNAA is used widely for extracting potassium from soils and commonly
used for extracting calcium, magnesium and sodium from soils. Some
areas also use NNAA extraction for phosphorus. Because of the presence
of ammonium, NNAA is not suited for the determination of potassium by
ion selective electrode. This method uses a neutral salt solution to replace
the cations present on the soil exchange complex. Therefore, the cation
concentrations determined by this method are referred to as
“exchangeable” for non-calcareous soils. For calcareous soils, the cations
are referred to as “exchangeable plus soluble.” The NNAA determination
applies to all classes of soils. The procedure is based on the Handbook on
Reference Methods for Soil Testing, 1980 edition, published by The
Council on Soil Testing and Plant Analysis.
44
NEUTRAL NORMAL AMMONIUM ACETATE EXTRACTION, continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Ammonium Acetate
Soil Extractant Concentrate .................................... 40 mL/8 test....... 1000 mL .......22666-53
REQUIRED APPARATUS
Bottle, polyethylene, 200 mL.............................................. 1........................each .........5909-00
Cap, 3-piece, w/screen ........................................................ 1........................each .........5912-00
Cylinder, graduated, polymethylpentene, 25 mL ................ 1....................... each .........2172-40
Cylinder, graduated, mixing, 50 mL ................................... 1....................... each .........1896-41
Filter Paper, circular, 15 mm ............................................... 1..................100/pkg ...........506-58
Funnel, poly, 82 mm............................................................ 1....................... each .......24155-82
Snap-top Container, 120 mL ............................................... 1....................... each .......25522-00
Soil Scoop, 4.25 cc, 5 g....................................................... 1....................... each .......26572-05
Soil Sieve............................................................................. 1....................... each .......46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each .......25568-00
Disposable Cups.....................................................................................2500/pkg .......22631-74
Disposable Lids, for cups .......................................................................3000/pkg .......22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack........................each .......22624-00
Filter Paper, for Filtration Assembly, pre-folded .....................................500/pkg .......22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V ...........................................................each .......22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 230V ...........................................................each .......22623-02
Weighing Paper ........................................................................................500/pkg .......14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
45
46
OLSEN SODIUM BICARBONATE EXTRACTION
Method 8100
For Soil Extraction
Used for Phosphorus and Potassium
1. Dry the soil sample.
2. Using a 1-gram
Screen it to a fineness of scoop, measure
0-2 mm with the Hach
one scoop of prepared
Soil Sieve.
soil into a 120-mL
snap-top container.
3. Using a 25-mL
Note: Careful preparation is
important to assure volumetric Note: A balance may be used
measurement of the
to weigh 1 gram of soil.
sample. See the introductory
sections for soil sampling and
sample preparation.
4. Add the contents of one
graduated cylinder,
Soil Extractant 3 Powder
transfer 20 mL of
Pillow to the container.
demineralized water into
the container.
5. Shake the container for 6. Using a plastic funnel
1 minute at 10-minute
and filter paper, filter the
intervals for 30 minutes.
extracted sample into
another 120-mL snap-top
Note: Follow the given
container. Save the
times carefully for best
results. Longer standing or filtered liquid (filtrate) for
shaking periods will yield a analysis. The filtrate is
higher phosphate reading. stable for about 4 hours.
Note: The Soil Shaker
(22623-00 or 22623-02)
and plastic cups can be
used for multiple samples.
Note: The Filtration
Assembly can be used for
multiple samples.
47
OLSEN SODIUM BICARBONATE EXTRACTION, continued
Summary of Method
The Olsen Sodium Bicarbonate Extractant is used widely for extracting
phosphorus from alkaline and calcareous soils and is sometimes used for
extracting potassium from neutral, alkaline and acid soils. The procedure
is based on the Handbook on Reference Methods for Soil Testing, 1980
edition, published by The Council on Soil Testing and Plant Analysis.
This extraction can be used for potassium determination with an ionselective electrode.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Soil Extractant 3 Powder Pillows ........................................1 ................... 25/pkg....... 20441-68
REQUIRED APPARATUS
Cylinder, graduated, mixing, 50 mL ....................................1 ...................... each......... 1896-41
Filter Paper, circular, 15 mm................................................1 ................. 100/pkg........... 506-58
Funnel, poly, 82 mm ............................................................1 ...................... each....... 24155-82
Snap-top Container, 120 mL................................................1 ...................... each....... 25522-00
Soil Scoop, 1 g .....................................................................1 ...................... each....... 26572-01
Soil Sieve .............................................................................1 ...................... each....... 46159-00
OPTIONAL APPARATUS
Balance, AccuLab Poclket Pro 150B ........................................................... each....... 25568-00
Disposable Cups .................................................................................... 2500/pkg....... 22631-74
Disposable Lids, for cups....................................................................... 3000/pkg....... 22632-74
Filtration Assembly w/ 10 funnels, cup rack and funnel rack ....................... each....... 22624-00
Filter Paper, for Filtration Assembly, pre-folded ..................................... 500/pkg....... 22633-56
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 115V........................................................... each....... 22623-00
Shaker Assembly, includes 4 sample racks, 2-speed shaker,
time switch, and shaker plate, 230V........................................................... each....... 22623-02
Weighing Paper ........................................................................................ 500/pkg....... 14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
48
POTASSIUM CHLORIDE EXTRACTION
Method 10080
For Soil Extraction
Used for Total Exchangeable Acidity
Preparing the Potassium Chloride Extractant
POTASSIUM
CHLORIDE
1. Add three 5-gram
2. Add demineralized
scoops of potassium
water to the dispensing
chloride salt to one of the bottle until the volume
flip-top dispensing bottles. reaches the bottom of
the neck.
3. Invert the bottle
4. Label the bottle with
several times to mix.
the extractant name to
avoid confusion when
working with other
extractants. The
Potassium Chloride
Extractant is now ready
for use. This is enough
KCl solution for 4 tests.
3. Using a 5-gram
4. Using the 50-mL
Note: A balance may be
used to weigh 15 grams of
potassium chloride.
Preparing the Soil
1. Dry the soil sample.
2. Place a funnel into a
Screen it to a fineness of 250-mL erlenmeyer
0-2 mm with the Hach
flask. Place a filter
Soil Sieve.
paper into a funnel
and moisten it with
Note: Careful preparation
demineralized water.
is important to assure
volumetric measurement
of the sample. See the
introductory sections
for soil sampling and
sample preparation.
scoop, measure one
scoop of the prepared
soil sample into the
funnel containing the
wetted filter paper.
graduated cylinder,
slowly add 50 mL of KCl
solution to the soil sample
in 10-mL increments over
a 2-hour period. After the
addition is complete, rinse
Note: A balance may be used
the soil sample twice with
to weigh 5 grams of soil.
10-mL aliquots of
demineralized water.
Collect all of the filtrate
from this step in the
250-mL erlenmeyer flask.
49
POTASSIUM CHLORIDE EXTRACTION, continued
5. Add demineralized
water to the 250-mL
erlenmeyer flask to about
the 75-mL mark to rinse
down the sides of the
flask. Use this filtrate for
the determination of total
exchangeable acidity.
Perform the analysis
within one hour.
Summary of Method
Exchangeable acidity (H+, Al3+) is replaced by potassium, and the filtrate is
titrated for total acids.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Potassium Chloride, 454 g ...........................................15 g/4 tests ............. 454 g........... 764-01
REQUIRED APPARATUS
Bottle, polyethylene, 200 mL ..............................................1 ...................... each......... 5909-00
Cap, 3-piece, w/ screen ........................................................1 ................. 100/pkg......... 5912-00
Cylinder, graduated, 50 mL .................................................1 ...................... each......... 1896-41
Filter Paper, circular.............................................................1 ...................... each........... 506-58
Flask, erlenmeyer, 250 mL ..................................................1 ...................... each........... 505-46
Funnel, polyethylene, 82 mm ..............................................1 ....................... each....... 24155-82
Soil Scoop, 5 g .....................................................................1 ....................... each....... 26572-05
Soil Sieve .............................................................................1 ....................... each....... 46159-00
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................. each....... 25568-00
Weighing Paper ........................................................................................ 500/pkg....... 14738-00
For technical support and ordering information, see General Infromation section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
50
Method 10079
For Soil Extraction
SATURATED SOIL PASTE
Used for pH and Soluble Salts
1 hour
1. Dry the soil sample.
2. Fill a 120-mL snapScreen it to a fineness of top container about half
0-2 mm with the Hach
full of soil.
Soil Sieve.
Note: A plastic cup can
Note: Careful preparation is be used instead of a
snap-top container.
important to assure
volumetric measurement
of the sample. See the
introductory sections for
soil sampling and
sample preparation.
3. While stirring with
a spatula, add
demineralized water
until the saturation
point is reached.
Note: At saturation, the
soil will:
a) glisten and reflect light
b) flow slightly when the
container is tipped and
jarred
c) slide freely and cleanly
from the spatula (does not
apply to soils with high
clay content)
d) not collect free water
in surface depressions
upon standing.
51
4. Cap the container and
let stand for one hour.
During this period, check
to see if the saturation
characteristics are still
met. If not, add more
water or soil, as required.
SATURATED SOIL PASTE, continued
5. Remove a portion of
the soil paste to a
100-mL beaker for
pH measurement.
6. Place a clean filter
7. Transfer the
paper in a Buchner funnel. saturated soil paste
from the beaker into
the funnel.
Note: Conductivity/salinity
is affected by minute
amounts of potassium
chloride resulting from pH
determination. Determine
conductivity/salinity before
measuring pH or perform
pH on a separate aliquot of
saturated paste.
5:00 to 10:00
minutes
9. Assemble the
filtering apparatus
(Figure 1). Begin
filtering by squeezing
the hand pump to create
a vacuum in the filtering
flask and receiving tube
(about 10 pumps).
Squeeze frequently to
speed filtration.
10. Filtration takes
11. Use the extract for
5-10 minutes. If the extract conductivity
does not begin to filter
measurement and
within 10 seconds, check soluble salts calculation.
the filter apparatus for
air leaks.
Note: Decrease filtration
time by increasing
the amount of paste in
the funnel.
52
8. Carefully smooth the
paste over the filter paper
with the spatula. The
paste should completely
cover the bottom of the
funnel to a depth of about
0.5 inch (12 mm).
SATURATED SOIL PASTE, continued
Saturation Extract Kit
The Hach Model 18700 Saturation Extract Kit contains the apparatus
necessary to prepare the saturated soil paste and filter the extract.
Assemble the filtering apparatus as shown in Figure 1. Use care when
attaching the receiving tube to prevent breaking the glass. A small bottle
of silicone oil is provided to lubricate and condition the rubber adapter.
Apply a few drops and rub it into the adapter to aid in attaching it to the
receiving tube and Buchner funnel.
Figure 1
Filtering Apparatus
Check the vacuum of the filtering apparatus by placing your hand firmly
on top of the Buchner funnel and squeezing the vacuum pump several
times. A distinct suction, which increases with each squeeze, should be
felt under your hand. Push the vacuum release switch to either side to
verify the suction releases. If the system is not operating properly, check
the adapter to ensure an air-tight fit with the flask and the funnel. Also,
make sure the slot in the adapter is clear and the tubing connections are
air-tight.
Summary of Method
The endpoint for mixing a saturated soil paste is reasonably definite.
Technique variations, such as adding almost all the water to the soil
sample before stirring, or adding the air-dried soil to a known amount of
water, do not appreciably affect the saturation percentage of most soils.
However, soils with very fine or very coarse textures require special
handling. In some clay soils, the amount of water that must be added can
53
SATURATED SOIL PASTE, continued
vary by 10% or more, depending on the rate of water addition and the
amount of stirring. The more rapidly water is added in relation to stirring,
the lower the saturation percentage may be. The lower value is desirable
to reduce the time and effort during mixing and also to minimize puddling
of the soil.
Researchers discovered the conductivity of the saturation extract may also
be used to measure salinity in peat soils. With air-dried peats, an
overnight wetting period is necessary to obtain a definite endpoint for the
saturated paste.
The saturation percentage of the soil represents its water-holding capacity.
It is calculated by dividing the weight of the water needed to reach
saturation by the weight of dry soil:
weight of water
Saturation % = ---------------------------------------- × 100
weight of soil
REQUIRED APPARATUS
Quantity Required
Per Test
Description
Unit
Cat. No.
Beaker, 100 mL....................................................................1 ....................... each....... 22994-42
Cylinder, graduated, polymethylpentene, 25 mL.................1 ...................... each......... 2172-40
Saturation Extract Kit ..........................................................1 ....................... each....... 18700-00
Snap-top Container, 120 mL................................................1 ...................... each....... 25522-00
Soil Sieve .............................................................................1 ...................... each....... 46159-00
Spatula .................................................................................1 ....................... each....... 12257-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
54
Method 10077
For Soil Extraction
SMP BUFFER EXTRACTION
Used for Lime Requirement Summary of Method
1. Dry the soil sample.
2. Using a 2-gram
Screen it to a fineness of scoop , measure
0-2 mm with the Hach
4 scoops of prepared soil
Soil Sieve.
into a 120-mL
snap-top container.
3. Using a 25-mL
graduated cylinder,
accurately measure
21 mL of demineralized
water and transfer it
Note: Careful preparation is
to the 120-mL
important to assure
Note: A balance may be used
snap-top containter.
volumetric measurement
to weigh 8 grams of soil.
of the sample. See the
introductory sections for
soil sampling and
sample preparation.
5. Using the spatula, stir
the slurry for 1 minute and
allow it to stand for
10 minutes. After 10
minutes, use the prepared
sample for lime
requirement determination
by measuring the
suspension pH.
Note: Rinse spatula with
demineralized water before
stirring additional samples.
55
4. Add the contents
of one Lime
Requirement Buffer
Pillow to the 120-mL
snap-top container.
SMP BUFFER EXTRACTION, continued
This method is used to determine the lime requirement of acid soils
(aqueous pH less than 6.5). The SMP soil buffer test is not generally
recommended for:
• soils having a lime requirement of less than 2 tons/acre or 2240 kg/Ha
of lime
• soils containing organic matter greater than 10%
• sandy soils
• soils with high levels of kaolinite and hydroxy oxides of aluminum
and iron in their clay formations.
The analysis of total exchangeable acidity may be more effective for
determining the lime requirement in soils not suited for the SMP buffer
method. The lime requirement of an acid soil is defined as the amount of
lime or other bases which, when incorporated with a given depth of acid
soil, increases the pH to some selected level. It is expressed as CaCO3
equivalent in tons/acre of plowed soil to a depth of 8 inches (20 cm), which
is equivalent to 2240 kg/ha CaCO3 to the same depth or 1.67 meq/100 g
soil. An acre of soil 8 inches deep is assumed to weigh 2,400,000 lbs.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Lime Requirement Buffer Pillow, 25/pkg............................1 ................... 50/pkg....... 14345-98
REQUIRED APPARATUS
Cylinder, graduated, polymethylpentene, 25mL..................1 ...................... each......... 2172-40
Snap-top Container, 120 mL................................................1 ...................... each....... 25522-00
Soil Scoop, 2 g .....................................................................1 ...................... each....... 26572-02
Soil Sieve .............................................................................1 ...................... each....... 46159-00
Spatula, stainless steel..........................................................1 ....................... each........... 561-62
OPTIONAL APPARATUS
Balance, AccuLab Pocket Pro 150B ............................................................ each....... 25568-00
Weighing Paper ........................................................................................ 500/pkg....... 14738-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
56
SECTION 4
SOIL ANALYSIS PROCEDURES
57
58
SOIL ANALYSIS PROCEDURES
4.1
Calculation of Cation Exchange Capacity and Percent Base Saturation for Soil
The calculation of cation exchange capacity and percent base saturation
requires previous determination of potassium, calcium + magnesium,
sodium, and lime requirement.
Determining the cation exchange capacity (CEC) of soils is important for
assessing supplement potassium needs and the appropriate quantity of
herbicides to apply to soils. Precise determination of CEC is time
consuming. Soil testing labs in regions with acidic to neutral (pH 7) soils
have determined that estimating the CEC by summing the exchangeable
K, Ca, Mg, and neutralizable acidity (lime requirement) is acceptable.
(See equation below.) Measurement of CEC for calcareous soils (pH 7)
may be inflated by the CaCO3 in the Mehlich 2 extract.
CEC meq/100 grams=
K + Ca + Mg + Na + (SMP Lime Requirement x 2)
The values for potassium, calcium, magnesium, and sodium are in meq/
100 g, not in ppm. Refer to the individual procedures to obtain the
proper units.
Note: Cation
values (K, Ca +
Mg, Na) must be
as meq/100 g.
Rarely would summation include a numeric value for both Sodium and
exchangeable acidity. Acidic soils have a lime requirement and are
typically low enough in sodium that its value is insignificant in the CEC
calculation. Soils that are alkaline have no lime requirement value and
therefore the value should not be included in the calculation.
[ K + Ca + Mg + Na ] × 100
% Base Saturation = --------------------------------------------------------------------CEC
59
60
Method 8213
For Soil
CALCIUM (10 - 4000 mg/L as CaCO3)
Using EDTA with a Digital Titrator
Prepare
Appropriate
Extract
1. Prepare a Mehlich 1,
2. Using a 1-mL
Mehlich 2, or Ammonium
Acetate soil extract
according to the
appropriate procedure
in the Soil Extraction
Procedures section of
this manual.
dropper, transfer 1 mL
of extract into a 125-mL
flask. Dilute with
demineralized water to
the 50-mL line.
3. Insert a clean delivery
tube into a 0.0800 M
EDTA titration cartridge.
Attach the cartridge to the
titrator body. See General
Description of the
Digital Titrator Manual
for assembly instructions
if necessary.
4. Hold the Digital
Titrator with the cartridge
tip pointing up. Turn the
delivery knob to eject air
and a few drops of titrant.
Reset the counter to zero
and wipe the tip.
Note: For added
convenience use the
TitraStir® Stirring
Apparatus, see General
Description, Step 3 in
Step-by-Step, of the
Digital Titrator Manual.
5. Add 2 mL of 8N
Potassium Hydroxide
Standard Solution, and
swirl to mix.
6. Add the contents of
7. Place the delivery
8. Calculate the final
one CalVer® 2 Indicator tube tip into the solution. concentration:
Powder Pillow and swirl While titrating, swirl the For Ammonium Acetate and
Mehlich 1:
flask until the solution
to mix.
Digits Required ÷ 10 =
changes from red to pure meq/100 g Ca
Note: Magnesium is not
Note: A 0.1-gram scoop of
blue.
For Mehlich 2 SIW:
included in the results but CalVer 2 Hardness
Record the number of
Digits Required ÷ 5 =
must be present for a sharp Indicator Powder may be
meq/100 g Ca
digits required for the
end point.
substituted in this step.
For Mehlich 2:
color change.
Note: Titrate slowly near
the end point because the
reaction is slow, especially
in cold samples.
61
Digits Required ÷ 5.88 =
meq/100 g Ca
Conversion to ppm:
meq/100 g Ca x 200 =
ppm Ca
CALCIUM, continued
Summary of Method
The sample is made alkaline (pH 12-13) with potassium hydroxide to
precipitate magnesium as magnesium hydroxide. CalVer 2 Indicator is
added and combines with any calcium to form a pink-red color. As EDTA
is added, it reacts with the free calcium ions present. When no free
calcium ions remain, the EDTA then removes the calcium complexed
with the indicator causing a color change to blue.
REQUIRED REAGENTS
Total Hardness Reagent Set (about 100 tests) .............................................................. 22720-00
10-160 mg/L: Includes: (1) 282-32, (1) 852-99, (1) 14364-01
Quantity Required
Per Test
Description
Unit
Cat. No.
CalVer 2 Indicator Powder Pillows................................ 1 pillow............ 100/pkg........... 852-99
EDTA Titration Cartridge, 0.0800 M...................................1 ....................... each....... 14364-01
Potassium Hydroxide Standard Solution, 8.00 N ............ 2 mL .....100 mL MDB........... 282-32
Water, demineralized, 4 L ................................................ varies...................... 4 L........... 272-56
REQUIRED APPARATUS
Clippers, for opening pillows, each .....................................1 ....................... each........... 968-00
Digital Titrator .....................................................................1 ....................... each....... 16900-01
Dropper, glass ......................................................................1 ....................... each....... 14197-05
Flask, erlenmeyer, 125 mL ..................................................1 ....................... each........... 505-46
62
CALCIUM, continued
OPTIONAL REAGENTS
Description
Unit
Cat. No.
Calcium Chloride Standard Solution, 1000 mg/L as CaCO3 ................. 1000 mL ...........121-53
CalVer 2 Calcium Indicator Powder............................................................. 113 g ...........281-14
Calcium Hardness Standard Solution, Voluette Ampule
10,000 mg/L as CaCO3, 10 mL...............................................................16/pkg .........2187-10
Magnesium Standard Solution, 10 g/L as CaCO3 ................................29 mL DB .........1022-33
Nitric Acid solution, 1:1................................................................. 100 mL MDB ...........425-32
Nitric Acid ACS ....................................................................................... 500 mL .........2540-49
Potassium Cyanide, ACS ............................................................................. 113 g ...........767-14
OPTIONAL APPARATUS
Description
Unit
Cat. No.
Bottle, wash, poly, 500-mL ............................................................................each ...........620-11
Clamp, extension ............................................................................................each .......21145-00
Clamp Holder .................................................................................................each ...........326-00
Delivery Tubes, straight, for Digital Titrator................................................5/pkg .......17205-00
Demineralizer assembly, 473 mL...................................................................each .......21846-00
pH electrode, Hach One Combination with Temp .........................................each .......48600-22
pH meter, EC 10, portable..............................................................................each .......50050-60
pH Paper, 1-11 pH units .......................................................................5 rolls/pkg ...........391-33
Pipet, TenSette®, 0.1 to 1.0 mL ......................................................................each .......19700-01
Pipet, Tips, for 19700-01 TenSette Pipet ...................................................50/pkg .......21856-96
Pipet, volumetric, Class A, 10 mL .................................................................each .......14515-38
Pipet, volumetric, Class A, 20 mL .................................................................each .......14515-20
Pipet, volumetric, Class A, 25mL ..................................................................each .......14515-40
Pipet, volumetric, Class A, 50 mL .................................................................each .......14515-41
Pipet, volumetric, Class A, 100 mL ...............................................................each .......14515-42
Pipet Filler, safety bulb...................................................................................each .......14515-00
Spoon, measuring, 0.1 gram...........................................................................each ...........511-00
Spoon, measuring, 0.5 gram...........................................................................each ...........907-00
Stir Bar Retriever, 45.7 cm (12”) long ...........................................................each .......15232-00
Support Stand .................................................................................................each ...........563-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
63
64
CALCIUM + MAGNESIUM (Total Hardness)
Method 10081
For Soil
Using EDTA with a Digital Titrator
Prepare
Appropriate
Extract
1. Prepare a Mehlich 1,
2. Using a 1-mL dropper, 3. Insert a clean delivery
Mehlich 2, or Ammonium
Acetate extract according
to the procedures in the
extraction section of
this manual.
accurately transfer 1 mL
of extract into a 125-mL
flask. Dilute with
demineralized water to
the 50-mL line.
tube into a 0.0800 M
EDTA titration cartridge.
Attach the cartridge to the
titrator body. See General
Description of the Digital
Titrator Manual for
assembly instructions
if necessary.
4. Hold the Digital
Titrator with the cartridge
tip pointing up. Turn the
delivery knob to eject air
and a few drops of titrant.
Reset the counter to zero
and wipe the tip.
Note: For added
convenience use the
TitraStir® Stirring
Apparatus, see General
Description, Step 3 in
Step-by-Step, of the
Digital Titrator Manual.
65
CALCIUM + MAGNESIUM, continued
5. Add 1mL of Buffer
Solution, Hardness 1,
and swirl to mix.
6. Add the contents of
7. Place the delivery tube 8. Calculate the final
one ManVer 2 Indicator tip into the solution.
concentration:
Powder Pillow and swirl While titrating, swirl the For Ammonium Acetate,
Mehlich 1, and Soil Extract 2:
to mix.
flask until the solution
changes from red to pure Digits Required ÷ 10 =
Note: Four drops of
blue. Record the number meq/100 g Ca + Mg
ManVer Hardness
of digits required for the For Mehlich 2:
Indicator Solution or a
Digits Required ÷ 5 =
0.1-gram scoop of ManVer color change
2 Hardness Indicator
Powder may be substituted
in this step.
Note: Titrate slowly near
the end point because the
reaction is slow, especially
in cold samples.
meq/100 g Ca + Mg
For Mehlich 2 (1:8.5
dilution):
Digits Required ÷ 5.88 =
meq/100 g Ca + Mg
Conversion to ppm:
meq/100 g Ca + Mg x 200 =
ppm Ca + Mg
Accuracy Check
To verify test results when interferences are suspected or to verify
analytical technique:
1. Snap the neck off a Hardness Voluette® Ampule Standard, 10,000 mg/L
as CaCO3.
2. Use a TenSette® Pipet to add 0.1 mL of standard to the sample titrated
in Step 7. Resume titration back to the same end point. Record the
number of digits required.
3. Repeat, using two more additions of 0.1 mL. Titrate to the end point
after each addition.
4. Each 0.1 mL addition of standard should require 10 additional digits of
0.800 M titrant, 100 digits of 0.0800 M titrant, 11 digits of 0.714 M, or 56
digits of 0.1428 M titrant. If these uniform increases do not occur, refer to
Standard Additions, Section I, of the DR/2010 Spectrophotometer
Procedures Manual to determine the cause.
66
CALCIUM + MAGNESIUM, continued
Summary of Method
After the sample is buffered to pH 10.1, ManVer 2 Hardness Indicator is
added and forms a red complex with a portion of the calcium and
magnesium in the sample. The EDTA titrant reacts first with the free
calcium and magnesium ions in the sample, then with those bound to the
indicator causing a change to a blue color at the end point.
REQUIRED REAGENTS
Total Hardness Reagent Set (about 100 tests) ..............................................................24480-00
10-160 mg/L: Includes: (1) 424-32, (1) 851-99, (1) 14364-01
Quantity Required
Per Test
Description
Unit
Cat. No.
Buffer Solution, Hardness 1 ............................................. 1 mL..... 100 mL MDB ...........424-32
EDTA Titration Cartridge, 0.0800 M .................................. 1........................each .......14364-01
ManVer 2 Hardness Indicator Powder Pillow ................1 pillow ............100/pkg ...........851-99
Water, demineralized, 4 L ............................................... varies ......................4 L ...........272-56
REQUIRED APPARATUS
Clippers, for opening pillows, each..................................... 1........................each ...........968-00
Digital Titrator..................................................................... 1........................each .......16900-01
Dropper, glass...................................................................... 1........................each .......14197-05
Flask, erlenmeyer, 250 mL.................................................. 1........................each ...........505-46
Select one or more based on sample volume
Cylinder, graduated, 10-mL ................................................ 1........................each ...........508-38
Cylinder, graduated, 25-mL ................................................ 1........................each ...........508-40
Cylinder, graduated, 50-mL ................................................ 1........................each ...........508-41
Cylinder, graduated, 100-mL .............................................. 1........................each ...........508-42
OPTIONAL REAGENTS
Ammonium Hydroxide, 10% ......................................................... 100 mL MDB .......14736-32
Calcium Chloride Standard Solution, 1000 mg/L as CaCO3 ................. 1000 mL ...........121-53
CDTA Magnesium Salt Powder Pillows ..................................................100/pkg .......14080-99
CDTA Titration Cartridge, 0.0800 M.............................................................each .......14402-01
CDTA Titration Cartridge, 0.800 M...............................................................each .......14403-01
EDTA Titration Cartridge, 0.714 M ...............................................................each .......14959-01
EDTA Titration Cartridge, 0.1428 M .............................................................each .......14960-01
Hardness Standard Solution, Voluette Ampule,
10,000 mg/L as CaCO3, 10 mL...............................................................16/pkg .........2187-10
Hydroxylamine Hydrochloride, monohydrate ............................................. 113 g ...........246-14
ManVer 2 Hardness Indicator Powder.......................................................... 113 g ...........280-14
Nitric Acid solution, 1:1................................................................. 100 mL MDB ...........425-32
Nitric Acid ACS ....................................................................................... 500 mL .........2540-49
Potassium Cyanide, ACS ............................................................................. 113 g ...........767-14
67
CALCIUM + MAGNESIUM, continued
OPTIONAL APPARATUS
Description
Unit
Cat. No.
Bottle, wash, poly, 500-mL............................................................................ each........... 620-11
Clamp, extension ........................................................................................... each....... 21145-00
Clamp Holder................................................................................................. each........... 326-00
Clipper, shears, 7 1/4”.................................................................................... each....... 23694-00
Delivery Tubes, straight, for Digital Titrator ............................................... 5/pkg....... 17205-00
Demineralizer assembly, 473 mL .................................................................. each....... 21846-00
pH electrode, Hach One Combination with Temp......................................... each....... 48600-22
pH meter, EC 10, portable ............................................................................. each....... 50050-60
pH Paper, 1-11 pH units....................................................................... 5 rolls/pkg........... 391-33
Pipet, TenSette, 0.1 to 1.0 mL........................................................................ each....... 19700-01
Pipet, Tips, for 19700-01 TenSette Pipet ................................................... 50/pkg....... 21856-96
Pipet, volumetric, Class A, 10 mL................................................................. each....... 14515-38
Pipet, volumetric, Class A, 20 mL................................................................. each....... 14515-20
Pipet, volumetric, Class A, 25mL.................................................................. each....... 14515-40
Pipet, volumetric, Class A, 50 mL................................................................. each....... 14515-41
Pipet, volumetric, Class A, 100 mL............................................................... each....... 14515-42
Pipet Filler, safety bulb .................................................................................. each....... 14515-00
Spoon, measuring, 0.1 gram .......................................................................... each........... 511-00
Spoon, measuring, 0.5 gram .......................................................................... each........... 907-00
Spoon, measuring, 1.0 gram .......................................................................... each........... 510-00
Stir Bar Retriever, 45.7 cm (12”) long........................................................... each....... 15232-00
Support Stand................................................................................................. each........... 563-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
68
Method 8030
For Soil
CALCIUM + MAGNESIUM
Calcium and Magnesium; Calmagite Colorimetric Method
522 nm
Prepare
Appropriate
Extract
1. Enter the stored
program number for
magnesium.
Press: 2 2 5 ENTER
The display will show:
Dial nm to 522
Note: The Pour-Thru Cell
can be used if rinsed well
with demineralized water
between the blank and
prepared sample.
2. Rotate the
3. Prepare an
wavelength dial until the Ammonium Acetate,
small display shows:
Mehlich 1, or Mehlich 2
soil extract according to
522 nm
the appropriate
When the correct
procedure in the Soil
wavelength is dialed in, Extraction Procedures
the display will quickly section of this manual.
show: Zero Sample
4. Using a 1-mL,
serological pipet
accurately transfer 0.2
mL of extract into a 100mL graduated mixing
cylinder. Dilute to the
100-mL mark with
demineralized water.
Note: For the most accurate
magnesium test result the
sample temperature should be
between 21-29 °C (70-84 °F).
then:
mg/L Mg-CaCO3
5. Add 1.0 mL of
6. Add 1.0 mL of
Calcium and
Magnesium Indicator
Solution using a
1.0-mL measuring
dropper. Stopper. Invert
several times to mix.
Alkali Solution for
Calcium and
Magnesium Test using a
1.0-mL measuring
dropper. Stopper. Invert
several times to mix.
7. Pour 25 mL of the
solution into each of
three sample cells.
Note: The test will detect
any calcium or magnesium
contamination in the mixing
cylinder, measuring droppers
or sample cells. To test
cleanliness, repeat the test
multiple times until you
obtain consistent results.
69
8. Add one drop of
1 M EDTA Solution to
one cell (the blank).
Swirl to mix.
CALCIUM + MAGNESIUM, continued
10. Place the blank into 11. Press: ZERO
9. Add one drop of
EGTA Solution to
the cell holder. Close the
The display will show:
another cell (the
light shield.
prepared sample for Mg).
Zeroing. . .
Swirl to mix.
then:
12. Place the prepared
sample into the cell
holder. Close the
light shield.
0.00 mg/L Mg-CaCO3
Use the arrow keys to
select the “Mg” form
of measurement.
13. Press: READ
The display will show:
Reading. . .
then the result in mg/L
Mg as CaCO3 will be
displayed.
Note: mg/L total hardness
equals mg/L Ca as CaCO3
plus mg/L Mg as CaCO3.
14. If using the
Ammonium Acetate or
Mehlich 1 extract,
multiply the number by
2500. If using the
Mehlich 2 extract
multiply by 4250. If
using Mehlich 2 SIW,
multiply by 5000.
15. Press:
SELECT PRGM
16. Enter the stored
program number for
calcium.
Press: 2 2 0 ENTER
The display will
quickly show:
Zero Sample
then:
Record the answer as
ppm Mg.
mg/L Ca-CaCO3
Note: Do not remove
sample cell from the
previous reading.
Note: ppm Mg ÷ 120 =
meq/100g Mg.
70
CALCIUM + MAGNESIUM, continued
17. Press: ZERO
The display will show:
18. Place the third
sample cell into the
cell holder.
19. Press: READ
The display will show:
Zeroing. . .
Reading. . .
then:
0.00 mg/L Ca-CaCO3
Use the arrow keys to
select the “Ca” form of
measurement.
then the result in mg/L
Ca as CaCO3 will be
displayed.
Note: mg/L total hardness
equals mg/L Ca as CaCO3
plus mg/L Mg as CaCO3.
20. If using the
Ammonium Acetate or
Mehlich 1 extract,
multiply the number by
2500. If using the
Mehlich 2 extract
multiply by 4250. If
using Mehlich 2 SIW,
multiply by 5000.
Record the answer as
ppm Ca.
Note: ppm Ca ÷ 200 =
meq/100g Ca.
Precision
In a single laboratory using a standard solution of 1.5 mg/L Mg as CaCO3 and
3 mg/L Ca as CaCO3 with the DR/2010, a single operator obtained a standard
deviation of ± 0.006 mg/L Mg as CaCO3 and ± 0.02 mg/L Ca as CaCO3.
71
CALCIUM + MAGNESIUM, continued
Interferences
• For the most accurate calcium test result, the test should be rerun on a
diluted sample if the calcium is more than 1.0 and the magnesium is
more than 0.25 mg/L as CaCO3. No retesting is needed if either is less
than these respective concentrations.
• The following ions cause a detectable error in test results.
Interfering Ions
Cr3+
0.25 mg/L
Cu2+
0.75 mg/L
EDTA, chelated
0.2 mg/L as CaCO3
Fe2+
1.4 mg/L
Fe3+
2.0 mg/L
Mn2+
0.20 mg/L
Zn2+
0.050 mg/L
• Traces of EDTA or EGTA remaining in sample cells from previous
tests will give erroneous results. Rinse cells thoroughly before using.
Alternate Methods
Hach offers alternate methods for Ca + Mg hardness using EDTA titration.
Calcium can also be determined using EDTA titration and ISE. Contact your
Hach representative.
Summary of Method
The colorimetric method for measuring hardness supplements the
conventional titrimetric method because it can measure very low levels of
calcium and magnesium. Also some interfering metals (those listed
above) in the titrimetric method are inconsequential in the colorimetric
method when diluting the sample to bring it within the range of this test.
The indicator dye is calmagite which forms a purplish-blue color in a
strongly alkaline solution and changes to red when it reacts with free
calcium or magnesium. Calcium and magnesium determinations are
made by chelating calcium with EGTA to destroy any red color due to
calcium and then chelating the calcium and magnesium with EDTA to
destroy the red color due to both calcium and magnesium. By measuring
the red color in the different states, calcium and magnesium
concentrations are determined.
72
CALCIUM + MAGNESIUM, continued
REQUIRED REAGENTS
Hardness Reagent Set (100 Tests) .................................................................................23199-00
Includes: (1) 22417-32, (1) 22418-32, (1) 22419-26, (1) 22297-26
Quantity Required
Per Test
Description
Unit
Cat. No.
Alkali Solution for Calcium and Magnesium Test........... 1 mL............... 100 mL .......22417-32
Calcium and Magnesium Indicator Solution.................... 1 mL............... 100 mL .......22418-32
EDTA Solution, 1 M ....................................................... 1 drop................ 50 mL .......22419-26
EGTA Solution ............................................................... 1 drop................ 50 mL .......22297-26
REQUIRED APPARATUS
Cylinder, 100-mL mixing.................................................... 1........................each .........1896-42
Dropper, measuring, 0.5 and 1.0 mL................................... 2....................20/pkg .......21247-20
Pipet, serological, 1 mL....................................................... 1........................each .........9190-02
Sample Cell, 25 mL, matched pair...................................... 2............................. 2 .......20950-00
OPTIONAL APPARATUS
Pipet Filler ......................................................................................................each .......12189-00
Pour-Thru Cell Assembly Kit .......................................................................each .......45215-00
pH Meter, EC10, portable ..............................................................................each .......50050-60
Thermometer, -10 to 110 °C...........................................................................each .........1877-01
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
73
74
Method 10078
For Soil
GYPSUM REQUIREMENT
EDTA Titration Method Using Digital Titrator
Perform a
Ca2SO4 Extraction
1. Obtain a calcium
sulfate extract for the soil
sample by performing the
Saturated Calcium Sulfate
Extraction procedure in
Section 3.
5. Add 5 mL of
2. Insert a clean delivery
tube into a 0.8 M EDTA
Titration Cartridge.
Attach the cartridge to
the titrator body. See
General Description
Section, Step-by-Step of
the Digital Titrator
Manual for assembly
instructions.
6. Add demineralized
Saturated Calcium Sulfate water to about the 25-mL
Extractant to another
mark of each flask.
50-mL erlenmeyer flask.
3. Hold the Digital
4. Using a 10-mL
Titrator with the cartridge
tip pointing up. Turn the
delivery knob to eject air
and a few drops of titrant.
Reset the counter to zero
and wipe the tip.
serological pipet,
accurately transfer 5.0 mL
of the soil sample extract
prepared in Step 1 to a
50-mL erlenmeyer flask.
7. Add 1.0 mL of Buffer
Hardness 1 solution to
each flask and swirl
to mix.
8. Add the contents of
Note: The volume must be
transferred accurately.
Note: For added
convenience use the
TitraStir® Stirring
Apparatus, see General
Description, Step 3 in
Step-by-Step, of the Digital
Titrator Manual.
one ManVer® 2 Hardness
Indicator Powder Pillow to
each flask and swirl to mix.
Note: Four drops of
ManVer Hardness
Indicator Solution or a
0.1-g scoop of ManVer 2
Hardness Indicator Powder
may be substituted here.
75
GYPSUM REQUIREMENT, continued
9. Place the delivery tip 10. Repeat Step 9
into the sample solution titrating 5 mL of the
and swirl the flask
Saturated Calcium
while titrating with EDTA Sulfate Extractant.
from red to pure blue.
Record the number of
digits required.
Note: Titrate slowly near
the endpoint because the
reaction is slow, especially
in cold samples.
11. Calculate the gypsum
requirement using the
calculations following
these steps.
12. When analysis is
complete, rinse the
labware with
demineralized water.
Note: If the number of
digits of titrant required for
the sample extract is equal
to or greater than the
number of digits required
for the Saturated Calcium
Sulfate Extractant, then no
gypsum requirement exists.
Calculations
Gypsum Requirement (GR) in meq/100 gms =
 Digits Required for Sat′d × 4  – ( Digits Required for × 4 ) ] × 2
 C SO E
Gypsum Requirement (Tons/Acre at a depth of 6 inches) =
GR meq/100 g x 1.7
Gypsum Requirement (Metric Tons/ha at a depth of 15 cm) =
GR meq/100 g x 3.81
Estimated Exchangeable Sodium (meq/100 g) =
[0.96 + (0.99 x GR meq/100 g)]
Example
The analyst titrates 5.0 mL of Saturated Calcium Sulfate solution and it
requires 70 digits of EDTA to obtain the endpoint. The soil extract
requires 65 digits.
GR, meq/100 g = [(70 x .4) - (65 x .4)] x 2 = 8 meq/100 g
GR, Tons/Acre = 8 x 1.7 = 13.6 Tons/Acre
GR, Kg/ha = 8 x 3.81 = 30.48 metric Tons/Acre
Est. Exch. Sodium (meq/100 g)= [0.96 + (0.99 x 8)] = 8.88 meq/100 g
76
GYPSUM REQUIREMENT, continued
Summary of Method
Gypsum Requirement is calculated by subtracting the amount of EDTA
required to titrate the extracted soil from the amount of EDTA required to
titrate the extractant. Then the relationship between exchangeable sodium
and gypsum requirement is calculated.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
EDTA Titration Cartridge, 0.800 M ................................ varies ....................each .......14399-01
Hardness 1 Buffer, 100 mL .............................................. 1 mL..... 100 mL MDB ...........424-32
ManVer 2 Hardness Indicator Powder Pillow ................1 pillow ............100/pkg ...........851-99
REQUIRED APPARATUS
Cylinder, graduated, 25 mL................................................. 1....................... each .........2172-40
Digital Titrator..................................................................... 1....................... each .......19600-01
Flask, erlenmeyer, 50 mL.................................................... 1....................... each ...........505-41
Pipet, Serological, 10 mL.................................................... 1........................each ...........532-38
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
77
78
LIME ESTIMATION, FREE (EXCESS)
Method 10096
For Soil
Effervescence Method
FILL LINE
1. Using a 1-g scoop,
2. Add demineralized
measure one scoop of the water dropwise to the
prepared soil sample onto soil until it is minimally
the watch glass provided. saturated. This expels
air from the sample,
Note: Several samples may
preventing erroneous
be analyzed on the watch
glass. Use the laboratory pen results.
to divide the watch glass into
sections and carefully label
each section. Use one section
per sample. Use care to
prevent cross contamination
between samples.
3. Add 3 drops of
4. Record whether the
2.5 N HC1 to each soil soil is non-calcareous,
sample and note the
slightly, moderately, or
degree of effervescence. highly calcareous.
Note: It is helpful when first
learning this procedure to
test several soils of known
pH and/or lime content to
use as references.
Accuracy check
When learning this procedure, it is helpful to test several soils of known
pH and/or lime content to use as references.
Summary of Method
A calcareous soil is alkaline in pH because it contains calcium carbonate
particles. Calcareous soils effervesce (fizz) when treated with 2.5 N
hydrochloric acid (HCl). The degree of effervescence determines whether
the soil is non-calcareous, slightly, moderately, or highly calcareous.
Calcareous soils present several problems to crop management. While the
soils are highly buffered against acidity (high percent base saturation), the
alkaline pH reduces the availability of phosphorus, iron, zinc, manganese,
copper and boron.
79
LIME ESTIMATION, FREE (EXCESS), continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Hydrochloric Acid Standard Solution, 2.5 N..................3 drops .............100 mL......... 1418-32
REQUIRED APPARATUS
Pen, Laboratory....................................................................1 ....................... each....... 20920-00
Soil Scoop, 1 g .....................................................................1 ....................... each....... 26572-01
Watch Glass, Pyrex ..............................................................1 ....................... each........... 578-67
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
80
Method 8039
For Soil
NITRATE, HR (0 to 60 ppm NO3--N)
Cadmium Reduction Method
500 nm
Preform a
Ca2SO4
Extraction
1. Prepare a Calcium
2. Enter the stored
Sulfate extract according
to the procedure in the
Soil Extraction
Procedures section of
this manual.
program number for
high range nitrate
nitrogen (NO3--N)
powder pillows.
3. Rotate the
4. Fill a sample cell
wavelength dial until the with 25 mL of sample.
small display shows:
500 nm
When the correct
wavelength is dialed in,
the display will quickly
show: Zeroing. . .
Press: 3 5 5 ENTER
The display will show:
DIAL nm TO 500
Note: The Pour-Thru Cell
can be used if rinsed well
with demineralized water
after use. Avoid pouring
any cadmium particles into
the cell.
then:
mg/L N NO3- HR
81
Note: A reagent blank must
be determined on each new
lot of NitraVer® 5 Reagent.
Perform Steps 3 to 11 using
demineralized water as the
sample. Subtract this value
from each result obtained
with this lot of reagent.
NITRATE, HR, continued
5. Add the contents of
one NitraVer 5 Nitrate
Reagent Powder Pillow
to the cell (the prepared
sample). Stopper.
6. Press: SHIFT TIMER 7. When the timer
8. Fill another sample
Shake the cell vigorously beeps, press:
until the timer beeps in
SHIFT TIMER
one minute.
A five-minute reaction
Note: A deposit of
period will begin.
cell with 25 mL of
sample (the blank).
unoxidized metal will remain
Note: An amber color will
after the NitraVer 5 Nitrate
develop if nitrate nitrogen
Reagent Powder dissolves
is present.
and will not affect results.
Note: Shaking time and
technique influence color
development. For most
accurate results, make
successive tests on a 10 mg/L
Nitrate Nitrogen Standard
Solution. Adjust the shaking
time to obtain the correct result.
82
NITRATE, HR, continued
9. When the timer
beeps, the display
will show:
mg/L N NO3- HR
10. Press: ZERO
Place the blank into the
cell holder. Close the
light shield.
then:
Note: The Pour-Thru Cell
can be used if rinsed well
with demineralized water
after use. Avoid pouring
any cadmium particles into
the cell.
Place the prepared sample
The display will show:
into the cell holder. Close
the light shield.
Reading. . .
The display will show:
Zeroing. . .
Note: A cadmium deposit
0.0 mg/L N NO3- HR will remain after the
NitraVer 5 Nitrate Reagent
Powder dissolves and will
not affect results.
then the result in mg/L
nitrate nitrogen (NO3--N)
will be displayed.
Rinse the sample cell
immediately after use
to remove all
cadmium particles.
13. Calculate:
Multiply the results by 2
and record as ppm
nitrate nitrogen. To
convert from ppm to
other units, see Table 1.
11. Remove the stopper. 12. Press: READ
Table 1 Conversion Factors
To Convert
From
To
ppm
lbs/acre
0.3 x sample depth (inches)
ppm
kg/ha
0.1344 x sample depth (cm)
Multiply by
Note: mg/L = ppm
83
NITRATE, HR, continued
Accuracy Check
Standard Additions Method
a) Snap the neck off a fresh High Range Nitrate Nitrogen Voluette
Ampule Standard, 500 mg/L NO3--N.
b) Use the TenSette Pipet to add 0.1, 0.2, and 0.3 mL of standard to
three 25-mL extracts. Mix each thoroughly.
c) Analyze each sample as described above. The nitrogen concentration
should increase 2.0 mg/L as read on the DR/2010 Spectrophotometer,
for each 0.1 mL of standard added.
d) If these increases do not occur, see Standard Additions in Section I
of the DR/2010 Spectrophotometer Procedures Manual for
more information.
Standard Solution Method
Use a 10.0 mg/L Nitrate Nitrogen Standard Solution listed under Optional
Reagents to check test accuracy. Or, this can be prepared by diluting 1.00 mL
of solution from a High Range Nitrate Nitrogen Voluette Ampule Standard
Solution, 500 mg/L NO3--N, to 50.0 mL with demineralized water.
Substitute this standard for the diluted extract and proceed with the test as
described in the procedure. The mg/L NO3--N reading should be 10.0 mg/L.
Precision
In a single laboratory using standard solutions of 20.0 mg/L nitrate
nitrogen (NO 3--N) and two representative lots of reagent with the
DR/2010 Spectrophotometer, a single operator obtained a standard
deviation of ± 0.8 mg/L nitrate nitrogen.
Interferences
• Strong oxidizing and reducing substances will interfere.
• Ferric iron causes high results and must be absent.
• Chloride concentrations above 100 mg/L will cause low results. The
test may be used at high chloride levels, but a calibration must be
performed using standards spiked to the same chloride concentration.
See User Stored Programs in the DR/2010 Spectrophotometer
Instrument Manual for more information.
• Highly buffered samples or extreme sample pH may exceed the buffering
capacity of the reagents and require sample pretreatment; see Section I,
pH, Interferences of the DR/2010 Spectrophotometer Procedures Manual.
84
NITRATE, HR, continued
Summary of Method
Cadmium metal reduces nitrates present in the sample to nitrite.
The nitrite ion reacts in an acidic medium with sulfanilic acid to
form an intermediate diazonium salt. This salt couples to gentisic
acid to form an amber-colored product.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
NitraVer 5 Nitrate Reagent Powder Pillows, 25 mL ......1 pillow ............100/pkg .......14034-99
REQUIRED APPARATUS
Clippers, for opening powder pillows ................................. 1........................each ...........968-00
Stopper, rubber, size 2 ......................................................... 1....................12/pkg .........2118-02
OPTIONAL REAGENTS
Nitrate Nitrogen standard Solution, 10 mg/L NO3--N.............................. 500 mL ...........307-49
Nitrate Nitrogen Standard Solution, Voluette Ampule, 500 mg/L
(NO3--N), 10 mL ..................................................................................16/pkg .......14260-10
Sodium Hydroxide Standard Solution, 5.0 N........................................... 59 mL* .........2450-26
Sulfuric Acid, ACS................................................................................. 500 mL* ...........979-49
Water, demineralized ........................................................................................4 L ...........272-56
OPTIONAL APPARATUS
Ampule Breaker Kit .......................................................................................each .......21968-00
Cylinder, graduated, 25 mL............................................................................each .........1081-40
Dropper, for 1-oz bottle..................................................................................each .........2258-00
pH Indicator Paper, 1 to 11 pH.............................................................5 rolls/pkg ...........391-33
pH Meter, EC10, portable ..............................................................................each .......50050-60
Pipet, serological, 2 mL..................................................................................each ...........532-36
Pipet, TenSette, 0.1 to 1.0 mL ........................................................................each .......19700-01
Pipet Tips, for 19700-01 TenSette Pipet ....................................................50/pkg .......21856-96
Pipet, volumetric, Class A, 1.00 mL ..............................................................each .......14515-35
Pipet Filler, safety bulb...................................................................................each .......14651-00
Pour-Thru Cell Assembly Kit ........................................................................each .......45215-00
Sample Cells, 1-inch, polystyrene, disposable...........................................12/pkg .......24102-12
Thermometer, -10 to 110 °C...........................................................................each .........1877-01
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
* Contact Hach for larger sizes.
85
86
Method 8097
For soil
ORGANIC MATTER (0 to 5.00%)
Dichromate Method
610 nm
1. Enter the stored
2. Rotate the
3. Weigh 1.00 g of soil 4. Pipet 10.0 mL of
wavelength dial until the and transfer to a 250-mL 1.000 N Potassium
small display shows:
erlenmeyer flask.
Dichromate
Solution into the
Note: If the soil contains
Press: 4 2 0 ENTER
610 nm
250-mL erlenmeyer
more than 5% organic
flask containing the
The display will show: When the correct
matter, use a smaller
wavelength is dialed in sample. For example, a
soil sample.
Dial nm to 610
the display will quickly 0.50-g sample will allow
Note: The Pour-Thru Cell show: Zero Sample
measurement of up to 10%
program number for
organic matter in soil.
can be used with
this procedure.
then:
% ORGANICS S
organic matter. If a sample
size other than 1.00 g is
used, multiply the results by
the factor (F):
F =
1.00 g
-----------------------------------------------------------------------actual sample size used (g)
5. Prepare a blank by
6. Pipet 20.0 mL of
pipetting 10.0 mL of
1.000 N Potassium
Dichromate Solution
into an empty 250-mL
erlenmeyer flask.
concentrated sulfuric
acid into each flask.
7. Cover each flask
with an inverted 50-mL
erlenmeyer flask. Swirl
gently to mix. Place on
cooling pads.
87
8. Press: SHIFT TIMER
A 10-minute reaction
period will begin.
ORGANIC MATTER, continued
10. Filter at least 25 mL
9. When the timer
beeps, the display will of the soil mixture into a
show:
50-mL erlenmeyer flask.
Do not filter the blank.
% ORGANICS S
Immediately use a
graduated cylinder to add
100 mL of demineralized
water to each flask. Swirl
briskly to mix.
Note: Do not use paper
filter. Use glass fiber filter.
As an alternative, allow the
sample to sit undisturbed
for 2 hours and decant
sample from the top of
the flask.
11. Pour 25 mL of the
12. Press: ZERO
blank into a sample cell
The display will show:
(the blank). Place the
blank into the cell holder.
Zeroing. . .
Close the light shield.
then:
Note: See Special Test
Considerations on the
following page.
13. Pour 25 mL of the
14. Press: READ
filtered soil solution into
The display will show:
a sample cell (the
prepared sample). Place
Reading. . .
the prepared sample into
then the result in %
the cell holder. Close the
organics will be displayed.
light shield.
Note: If the sample size
was not 1 gram, see note
under Step 3.
Note: Colorimetric
measurement of the filtrate
is slightly temperature
sensitive. The DR/2010
Spectrophotometer was
calibrated at room
temperature (~ 25 °C).
88
0.00% ORGANICS S
ORGANIC MATTER, continued
Accuracy Check
Standard Solution Method
Verify accuracy by using a CO2 Standard Solution Voluette Ampule, 46.4
g/L potassium hydrogen phthalate (KHP), listed under Optional Reagents.
Each mL of the standard is equivalent to a soil sample of 4.4% organic
matter. In Step 3 add the 1.00 mL of standard instead of the soil sample
and proceed with the test. The result should read 4.4% organic matter.
Precision
In a single laboratory using a potassium hydrogen phthalate standard
equivalent to 2.50% organic matter and two representative lots of reagent
with the DR/2010 Spectrophotometer, a single operator obtained a
standard deviation of ±0.017% organic matter.
Interferences
Interferences include chlorides, ferrous iron, nitrate and the higher oxides of
manganese. Chloride competes with organic carbon in reducing hexavalent
chromium; one milli-equivalent of chloride is equal in reducing capacity to
3.5 mg of carbon. The chloride error is normally low enough to ignore,
because 1% chloride in the soil would give an error of 0.1% (0.2% organic
matter). In air-dried soil any ferrous iron will be oxidized to the ferric form,
eliminating the interference from the ferrous form. Nitrate and manganese in
soils are normally at such a low level that any interferences are negligible.
Special Test Considerations
When testing several samples, add the soil and potassium dichromate
solution to all flasks (including the blank). Add the sulfuric acid to each
flask in sequential order at uniform time intervals (such as 30 seconds),
timing the 10-minute interval from the first flask. After 10 minutes, add
demineralized water to the flasks in the same order and the same interval.
This will give the proper 10-minute reaction time for each sample.
Because the reaction stops when the water is added, the time between
filtering and measurement is not critical. If convenient, allow the flasks to
stand for at least 3 hours. The soil should settle out; pipet 25 mL of the
clear solution for colorimetric measurement without filtering.
Use glass fiber filters to filter the soil residue from the solution. Fold the filter
disc in half and then in half again. Open the filter disc to form a cone and press
into the funnel. Pour the sample into the center of the filter, being careful not to
overflow the filter. At least 25 mL of filtrate is needed for analysis.
Cellulose filter papers of various grades have been tested for this method.
All have shown a reaction with the reagents causing higher readings.
Compensation for this effect may be possible by filtering the reagent
blank through an identical piece of filter paper. However, Hach
recommends using the specified glass fiber filter disc.
89
ORGANIC MATTER, continued
Summary of Method
Unlike mineral nutrients in soil such as nitrogen, phosphorus and
potassium, organic matter is a nondistinct component of soil. It is
measured by an approximate relationship with organic carbon.
Organic carbon is oxidized to carbon dioxide in the dichromate method
with a parallel reduction of hexavalent chromium (Cr6+) to trivalent
chromium (Cr3+) and an accompanying color change from orange to green.
The intensity of the green color is proportional to the trivalent chromium
concentration which is related to the organic matter content in the soil.
REQUIRED REAGENTS
Description
Quantity Required
Per Test
Unit
Cat. No.
Potassium Dichromate Solution, 1.000 N.................. 20 mL ................... 1 L ............. 21971-53
Sulfuric Acid, ACS .................................................... 40 mL ................ 2.5 L ................. 979-09
REQUIRED APPARATUS
Balance, Ohaus Model 505-10, 50 g...................................1 ..................each ............. 18475-00
Cylinder, graduated, 100 mL ..............................................1 ..................each ................. 508-42
Filter Disc, glass fiber filter, 9 cm ......................................1 ............100/pkg ............. 21987-55
Flask, erlenmeyer, 50-mL ...................................................2 ..................each ................. 505-41
Flask, erlenmeyer, 250-mL .................................................2 ..................each ................. 505-46
Funnel, analytical, poly, 65 mm..........................................1 ..................each ............... 1083-67
Pad, cooling, 4" x 4" ...........................................................2 ..................each ............. 18376-00
Paper, weighing, 76 x 76 mm .............................................1 ............500/pkg ............. 14738-00
Pipet, serological, glass, 10 mL ..........................................1 ..................each ................. 532-38
Pipet, serological, glass, 25 mL ..........................................1 ..................each ............... 2066-40
Pipet Filler, safety bulb .......................................................1 ..................each ............. 14651-00
Sample Cells, 25 mL, matched pair..........................................................pair ............. 20950-00
OPTIONAL REAGENTS
CO2 Standard Solution Voluette Ampule, 10,000 mg/L as CO2
(46.4 g/L Potassium hydrogen phthalate), 10 mL .......................16/pkg ............. 14275-10
Water, demineralized ................................................................................ 4 L ................. 272-56
OPTIONAL APPARATUS
Ampule Breaker Kit.................................................................................each ............. 21968-00
Pour-Thru Cell .........................................................................................each ............. 45215-00
Thermometer, -10 to 110 °C ....................................................................each ............... 1877-01
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
90
Method 8156
For Soil
pH
Hach One Combination pH Electrode Method with an EC10 Portable Meter
Sample pH Measurement (Calibration is required — see the following procedure)
Prepare an
Aqueous
Extract
2. Press the Dispenser
soil extract according to Button once (it will click).
the appropriate
Rinse and blot dry.
procedure in the Soil
Extraction Procedures
section, of this manual.
1. Prepare an Aqueous
3. Swirl the suspension to 4. Record the pH value
mix the soil and
water and place the
electrode in the container.
Be sure the entire sensing
end is submerged.
The Saturated Soil Paste
method also can be used.
See page 51.
FIL
L
when the display
stabilizes.
Note: If the pH of the soil
is less than 6.5, the soil
should be analyzed for
lime requirement.
Note: A stable reading is
difficult to obtain in a soil
matrix. If the reading
continues to fluctuate after
30 seconds, average the
fluctuating values to the
nearest 0.1 pH unit.
LIN
E
5. Rinse the electrode
thoroughly with
demineralized water and
blot dry.
91
pH, continued
Two-Standard Calibration in Automatic Mode with Temperature Probe
1. Press the POWER key. 2. Ensure the meter is in 3. Press the CAL key.
The display will light.
pH mode.
The slope data of the
previous calibration or
Note: Be sure no air
bubbles are trapped inside a default slope will
appear. Then the meter
the tip of the electrode or
will go into measure
dispenser tubing.
mode with “P1” (Point
1) in the display.
4. Place the electrode
into a pH 4 buffer
solution and press the
dispenser button. The
temperature will show
the actual solution
temperature and “ATC”
(Automatic Temperature
Compensation) will
Note: Hach buffers are
appear in the display if
available as powders or
the temperature probe
solutions. They are colorcoded for added convenience. is connected.
Note: Buffer solutions (pH
4, 7 and 10) may be used in
any order.
92
pH, continued
FIL
L
5. When the display
stabilizes, the meter will
beep and show the
temperature-corrected
value for the pH 4 buffer
and a ready indicator.
Press YES to accept this
value for the first buffer.
LIN
E
6. Rinse the electrode
7. Place the electrode in
with demineralized
the pH 7 buffer and press
water and blot dry with a the dispenser button.
paper towel.
8. When the display
stabilizes it will beep and
show the temperature
corrected value for the
pH 7 buffer and “ready”.
Press the YES key to
accept this value for the
second buffer.
Note: Pressing any key
other than the YES key at
this point will cancel the
calibration values entered
and the meter will default
to the previous slope and
adjust the offset only.
9. The slope will appear
in the display. It should
be 59.0 ±3 (mV/decade).
Press the YES key to
accept this slope. Rinse
the electrode with
demineralized water or a
portion of the sample to
be measured. Blot dry
with a paper towel.
10. Place the electrode
11. To review, press the
into the sample. Press
the Dispenser Button.
The meter will measure
the sample pH.
CAL key to show the
Note: Repeat step 10 for
each sample. Check the
calibration against a 7.0
pH Buffer after every 10
samples. A value outside of
the range of 6.95-7.05
indicates the analyst
should recalibrate.
electrode slope in the
display. The slope should
be 59.0 ± 3 mV/decade.
The meter will then attempt
to re-calibrate. Press
MODE again to return to
measurement mode.
Note: For other
calibrations or more
complete operation
instructions, refer to the
instrument manual.
93
pH, continued
Sampling and Storage
Determine pH within six hours. If samples cannot be analyzed within six hours,
report the actual holding time with the results.
Interferences
Acid error is negligible. Sodium error, usually present in alkaline
solutions, is low, but increases at pH values higher than pH 11.
Hach One pH Electode
Short-term Storage
Between measurements, store the electrode in a pH Electrode Storage
Solution. If electrode storage solution is not available, use one of the
following solutions:
• 200 mL of pH 7 buffer with one gram of potassium chloride added
(this is the preferred solution).
• pH 7 buffer solution.
For measurements of low-ionic strength sample, condition the electrode
by soaking in demineralized water for 1 to 2 hours.
Long-term Laboratory Storage
For storage greater than 2 weeks, continue to store the electrode in pH
Electrode Storage Solution. Maintain the AgCl concentration around the
wire by periodically (every few days) pumping electrolyte through the
electrode. Add demineralized water as needed to maintain the liquid level
around the electrode.
Long-term Field or Shelf Storage
Replace the black cap (Cat. No. 42389-00) that was on the electrode
when it was shipped. Periodically check the cotton ball in the tip of the
cap for moisture, adding a few drops of the pH electrode storage solution
when necessary.
If it becomes necessary to replace the cotton ball, add a few drops of pH
Electrode Storage Solution or pH 7 buffer to the replacement cotton and
place it into the end of the cap. Maintain the moisture as above. Salt
crystals may grow on the electrode tip. These are not harmful and may be
removed by rinsing the tip with demineralized water.
94
pH, continued
Normal Cleaning
If the electrode response time slows, the cause may be a fouled reference
element or a contaminated glass bulb. Normal cleaning or reconditioning
of the electrode can be performed in the following manner:
Immerse the electrode tip in 0.1N Hydrochloric Acid followed by
immersion in 0.1N Sodium Hydroxide and again in 0.1N Hydrochloric
Acid, each for a 2-minute period. Rinse with demineralized water and
soak in demineralized water for at least 15 minutes.
Remove oils and fats by immersing the electrode tip in a detergent
solution such as Alconox™. Use a brush or ultrasonic bath if necessary.
Avoid scratching the glass bulb.
Remove organic films from the glass bulb by using an appropriate
solvent, such as methanol or acetone.
If these steps fail to improve electrode response, replace the electrode.
EC10 Portable pH Meter Battery Replacement
Replace the 9V alkaline battery in the EC10 pH meter with a battery
of similar specifications (Hach Cat. No. 50110-00) when the display
dims. Refer to the meter manual for installation. Estimated battery life
is approximately 40 hours of use. An optional battery eliminator is
also available.
Summary of Method
The Hach One Combination pH Electrode responds to the hydrogen ion
concentration (activity) by developing an electrical potential at the glass/
liquid interface. At a constant temperature, this potential varies linearly
with the pH of the solution being measured. The electrode has a freediffusion junction which eliminates clogging problems.
REQUIRED REAGENTS AND APPARATUS
Description
Unit
Cat. No.
Buffer Powder Pillows, pH 4 and 7............................................................20/pkg .......22992-64
KCl Reference Electrode Gel Cartridge.......................................................2/pkg .......25469-02
Beaker, Griffin, 100 mL .................................................................................each .......22994-42
Clippers, for opening powder pillows ............................................................each ...........968-00
EC10 pH Meter and Hach One pH Electrode, case, accessories .......................... .......50050-10
Hach One Combination pH w/Temp (replacement).......................................each .......48600-22
95
pH, continued
OPTIONAL REAGENTS
Description
Unit
Cat. No.
Acetone, ACS ...........................................................................................500 mL....... 14429-49
Buffer Powder Pillows, pH 4 (red) ............................................................ 50/pkg....... 22269-66
Buffer Powder Pillows, pH 7 (yellow)....................................................... 50/pkg....... 22270-66
Buffer Powder Pillows, pH 9 ..................................................................... 50/pkg....... 14107-66
Buffer Powder Pillows, pH 10 (blue)......................................................... 15/pkg....... 22271-95
Buffer Solution, pH 4 (red).......................................................................500 mL....... 22834-49
Buffer Solution, pH 7 (yellow) .................................................................500 mL....... 22835-49
Buffer Solution, pH 10 (blue) ...................................................................500 mL....... 22836-49
Detergent Alconox ......................................................................................1.8 Kg....... 20880-00
Hydrochloric Acid Standard Solution, 0.1 N............................................... 1 liter....... 14812-53
pH Electrode Storage Solution .................................................................475 mL....... 50301-49
pH Electrode Storage Solution Powder Pillows .......................................... pk/20....... 26573-64
Sodium Hydroxide Standard Solution, 0.100N ........................................... 1 liter........... 191-53
Water, demineralized ....................................................................................... 4 L........... 272-56
OPTIONAL APPARATUS
Battery Eliminator, for EC10 pH Meter, 115 V, UL/CSA approved
with North American style plug ................................................................. each....... 50070-00
Battery Eliminator, for EC10 pH Meter, 230 V, VDE approved
with Continental European style plug ........................................................ each....... 50070-01
Battery, replacement, 9V .............................................................................. each....... 50110-00
Beaker, poly, 50 mL....................................................................................... each......... 1080-41
Clippers, for opening powder pillows............................................................ each........... 968-00
Cylinder, mixing, graduated, 50 mL .............................................................. each......... 1896-41
Electromagnetic stirrer and electrode holder, (115 V North American) ....... each....... 45300-01
Electromagnetic stirrer and electrode holder, (230 V)................................... each....... 45300-02
EC20 Portable pH/ISE Meter, Case Accessories (no electrode) ................... each....... 50075-10
EC30 Benchtop pH Meter with Hach One Electrode,
(115 V with North American style plug).................................................... each....... 50100-10
EC30 Benchtop pH Meter with Hach One Electrode,
(230 V with Continental European style plug)........................................... each....... 50100-11
EC40 Benchtop pH/ISE Meter with Hach One Electrode,
(115 V with North American style plug).................................................... each....... 50125-10
EC40 Benchtop pH Meter with Hach One Electrode,
(230 V with Continental European style plug)........................................... each....... 50125-11
CO150 Portable Conductivity Meter, Probe, Case Accessories .................... each....... 50150-00
Comb. pH Electrode with Temperature (Gel Filled)...................................... each....... 50200-00
Comb. pH Electrode (Refillable) ................................................................... each....... 50215-00
Temperature Probe ......................................................................................... each....... 50270-00
Stir Bar, 22.2 x 4.76 mm (7/8 x 3/16”) .......................................................... each....... 45315-00
Thermometer, armored, -10 to 110 °C........................................................... each......... 1877-01
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
96
PHOSPHORUS, REACTIVE (0 to 205 ppm P)
(Also called Orthophosphate)
PhosVer® 3 (Ascorbic Acid)
Method 8048
For Soil
Method
890 nm
Prepare
Appropriate
Extract
1. Prepare a Bray P1,
2. Enter the stored
Bray P2, Mehlich 1,
Mehlich 2, or Olsen
extract according to the
appropriate procedures
in the Soil Extraction
Procedures section of
this manual.
program number for
reactive phosphorus,
ascorbic acid method,
powder pillows.
Press: 4 9 0 ENTER
The display will show:
Dial nm to 890
Note: The Pour-Thru
Cell can be used for this
procedure, with 25-mL
reagents only.
3. Rotate the
wavelength dial until
the small display
shows:
890 nm
When the correct
wavelength is dialed in,
the display will quickly
show:
Zero Sample
then:
mg/L PO43- PV
Use the arrow keys to
select the “P” form of
phosphorus measurement.
97
4. Insert a 10-mL
Cell Riser into the
cell compartment.
PHOSPHORUS, REACTIVE, continued
5. If using an Olsen
extract, use a dropper
to transfer 3.0 mL of
soil extract into a
graduated cylinder. If
using any other extract,
pipet 1.0 mL of extract
into a graduated
cylinder.
6. Dilute to 25 mL
7. Fill a 10-mL sample
8. Add the contents of
with demineralized
water.
cell with the dilution.
one PhosVer® 3 Phosphate
Powder Pillow for 10-mL
sample to the cell (the
prepared sample). Shake
vigorously to mix.
Note: For Olsen, add 22 mL
of demineralized water. For
other extracts, use 24 mL of
demineralized water.
9. Press: SHIFT TIMER 10. Fill another
A two-minute reaction
period will begin.
sample cell (the blank)
with 10 mL of
demineralized water.
Note: For proof of
accuracy, use a 1.0 mg/L
Phosphate (0.33 mg/L P )
Standard Solution listed
under Optional Reagents in Note: A blue color will form
place of the diluted sample. if phosphate is present.
See Accuracy Check,
Standard Solution Method
following this procedure.
11. When the timer
12. Press: ZERO
beeps, the display will
show:
The display will show:
Zeroing. . .
mg/L P PV
Place the blank into
the cell holder. Close
the light shield.
98
then:
0.00 mg/L P PV
PHOSPHORUS, REACTIVE, continued
13. Place the prepared 14. Press: READ
sample into the cell
The display will show:
holder. Close the
light shield.
Reading. ..
15. Calculate:
Multiply by the
appropriate factor in
Table 1 and record
results as ppm P.
Note: Run a reagent blank then:
for this test. Use
demineralized water in place Results in mg/L P will
be displayed
of the sample in Step 5.
Subtract this result from all
test results run with this lot
of PhosVer 3 Reagent.
Note: mg/L = ppm (to
convert from ppm to other
units, see Table 2).
Table 1 Factors for Different Extracts
Extraction
Multiplication Factor
Bray P1
250
Bray P2
250
Mehlich 1
125
Mehlich 2
212.5
Mehlich 2 (SIW)
250
Olsen
167
Table 2 Conversion Factors
To Convert
From
To
ppm
lbs/acre
0.3 x sample depth (inches)
ppm
kg/ha
0.1344 x sample depth (cm)
99
Multiply by
PHOSPHORUS, REACTIVE, continued
Accuracy Check
Standard Additions Method
a) Fill three 25-mL graduated mixing cylinders with 25 mL of diluted
extract (from steps 5-6).
b) Snap the neck off a Phosphate Voluette Ampule Standard Solution,
50 mg/L PO43-.
c) Use the TenSette Pipet to add 0.1 mL, 0.2 mL and 0.3 mL of
standard, respectively, to the three 25-mL diluted extracts. Stopper
each and mix thoroughly.
d) Analyze each standard addition sample as described steps 7-14 of
the procedure. The phosphorus concentration as read on the
spectrophotometer should increase 0.067 mg/L P for each 0.1 mL
of standard added.
e) If these increases do not occur, see Standard Additions in Section I
of the DR/2010 Spectrophotometer Procedures Manual for
more information.
Standard Solution Method
For proof of accuracy, use a 1.0 mg/L Phosphate (0.33 mg/L P) Standard
Solution in place of the diluted sample. Step 14 results should read 0.33
mg/L P.
Alternately, prepare a 2.00 mg/L PO43- standard solution (0.67 mg/L as P)
by pipetting 4.0 mL of Phosphate Standard Solution, 50 mg/L as PO43-,
into a 100-mL volumetric flask. Dilute to volume with demineralized
water. Stopper and invert to mix. Use this solution in place of the sample
in the procedure to insure the accuracy of the test. The mg/L PO43- reading
should be 2.00 mg/L.
Interferences
Large amounts of turbidity may cause inconsistent results in the phosphate
tests because the acid present in the powder pillow may dissolve some of the
suspended particles and because of variable desorption of orthophosphate
from the particles. For highly turbid or colored samples, add the contents of
one Phosphate Pretreatment Powder Pillow to 10 mL of sample. Mix well.
Use this solution to zero the instrument.
• The PhosVer 3 Phosphate reagent Powder Pillows should be stored in
a cool, dry environment.
• Table 3 lists concentrations at which interferences occur.
100
PHOSPHORUS, REACTIVE, continued
Table 3 Interferences
Aluminum
200 mg/L
Chromium
100 mg/L
Copper
10 mg/L
Iron
100 mg/L
Nickel
300 mg/L
Silica
50 mg/L
Silicate
10 mg/L
Zinc
80 mg/L
• Arsenate and hydrogen sulfide interfere.
• Highly buffered samples or extreme sample pH may exceed the buffering
capacity of the reagents and require sample pretreatment; see Interferences,
pH, in Section I of the DR/2010 Spectrophotometer Manual.
Precision
In a single laboratory using a standard solution of 1.00 mg/L PO43- and
two lots of reagents with the DR/2010 Spectrophotometer, a single
operator obtained a standard deviation of ±0.01 mg/L PO43- .
Summary of Method
Orthophosphate reacts with molybdate in an acid medium to produce a
phosphomolybdate complex. Ascorbic acid then reduces the complex,
giving an intense molybdenum blue color.
101
PHOSPHORUS, REACTIVE, continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
PhosVer 3 Phosphate Reagent Powder Pillows
10 mL sample size ...................................................... 1 Pillow ............ 100/pkg....... 21060-69
OPTIONAL REAGENTS
Description
Unit
Cat. No.
Hydrochloric Acid Standard Solution, 6.0 N (1:1) ..................................500 mL........... 884-49
Mercuric Chloride Solution, 10 g/L .........................................................100 mL....... 14994-42
Phosphate Pretreatment Powder Pillows .................................................. 50/pkg....... 14501-66
Phosphate Standard Solution, 1 mg/L PO43- .............................................500 mL......... 2569-49
Phosphate Standard Solution, Voluette Ampule,
50 mg/L as PO4, 10 mL ...................................................................... 16/pkg........... 171-10
Sodium Chloride, ACS ............................................................................... 454 g........... 182-01
Sodium Hydroxide Standard Solution, 5.0 N ..............................100 mL* MDB......... 2450-32
Water, demineralized ....................................................................................... 4 L........... 272-56
OPTIONAL APPARATUS
Cylinder, graduated, mixing, 25 mL, tall....................................................... each....... 20886-40
pH Indicator Paper, 1 to 11 pH ........................................................... 5 rolls/pkg ........... 391-33
pH Meter, EC10, portable .............................................................................. each....... 50050-00
Pipet, 2 mL serological ................................................................................. each........... 532-36
Pipet, TenSette, 1.0 to 10.0 mL..................................................................... each....... 19700-10
Pipet Tips, for 19700-10 TenSette Pipet .................................................... 50/pkg...... 21997-96
Pipet Tips, for 19700-10 TenSette Pipet ................................................ 1000/pkg...... 21997-28
Pipet, TenSette, 0.1 to 1.0 mL TenSette Pipet ............................................... each....... 19700-01
Pipet Tips, for 19700-01 ........................................................................... 50/pkg....... 21856-96
Pipet Filler, safety bulb ................................................................................. each....... 14651-00
Spoon, measuring, 0.1 g ................................................................................ each........... 511-00
Thermometer, -10 to 110 °C .......................................................................... each......... 1877-01
OPTIONAL 25 ML ANALYSIS ITEMS
PhosVer 3 Phosphate Reagent
Powder Pillows, 25 mL sample size ..................................................... 100/pkg......... 2125-99
Pour-Thru Cell Assembly Kit ...................................................................... each...... 45215-00
Sample Cell, 25 mL matched pair ................................................................. pair....... 20950-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
* Larger sizes available.
102
Method 10085
For Soil
POTASSIUM (0 to 1170 ppm K)
Tetraphenylborate Method
650 nm
Prepare
Appropriate
Extractant
??
User
Calibration
1. Prepare a Neutral
2. This procedure
Normal Ammonium
Acetate, Mehlich 1,
Mehlich 2, Mehlich 2
(SIW), or Olsen extract
of the soil sample
according to the
appropriate procedure in
the Soil Extraction
Procedures section of
this manual.
requires a User-Entered
Calibration prior to
sample measurement. See
Calibration section
following this procedure.
Note: Because of potential
variation between lots of
Potassium 3 Reagent,
perform a new calibration
for each lot of reagent to
obtain best accuracy. For
more information about
User Entered Programs, see
Section 3 of the DR/2010
Spectrophotometer
Instrument Manual.
3. Enter the user-stored 4. Rotate the
program number for
wavelength dial until the
potassium (K) previously small display shows:
determined during the
650 nm
calibration below
When the correct
Press: 9 ? ? ENTER
wavelength is dialed in,
The display will show: the display will quickly
show: Zero Sample
DIAL nm TO 650
then:
Note: The Pour-Thru Cell
mg/L K
may be used with this
procedure. Flush the cell
with demineralized water
immediately after each
measurement.
103
POTASSIUM, continued
5. Using a dropper,
transfer 3.0 mL of the
soil extract into a
graduated cylinder.
6. Dilute to the
7. Using a dropper,
add 3 mL of Alkaline
EDTA Solution.
21-mL mark with
demineralized water.
Note: Filter highly colored
or turbid samples. Use
filtered sample here and
in Step 12.
9. Add the contents of
one Potassium 2
Reagent Pillow. Stopper.
Invert several times to
mix.
Note: Allow three minutes
for reaction.
10. Press: SHIFT TIMER
one Potassium 3 Reagent
A three-minute reaction
Pillow after the solution
period will begin.
clears. Stopper. Shake
for 30 seconds.
Note: A white turbidity will
form if potassium is present.
8. Add the contents of
11. Pour the solution
from the cylinder into a
sample cell (the
prepared sample).
Note: The Pour-Through
Cell may be used with this
procedure. Flush the cell
with demineralized water
immediately after each
measurement.
104
12. When the timer
beeps, the display
will show:
mg/L K
Fill the second sample
cell (the blank) with
25 mL of sample. Place
it into the cell holder.
POTASSIUM, continued
13. Press: ZERO
The display will show:
Zeroing. . . .
then:
0.0 mg/L K
14. Within seven
15. Press: READ
minutes after the timer
The display will show:
beeps, place the
prepared sample into the
Reading. . . .
holder. Close the light
then the result in
shield.
mg/L potassium will
be displayed.
16. Calculate:
Multiply the result by the
appropriate factor from
Table 1 and record the
results as ppm K. To
convert from ppm to other
units, see Table 2.
Note: Clean the cells with
soap and a brush.
Table 1 Factors for Different Extracts
Extraction
Multiplication Factor
Neu. Norm. Ammon. Acetate
41.67
Mehlich 1
41.67
Mehlich 2
71
Mehlich 2 (SIW)
83.3
Olsen
167
Table 2 Conversion Factors
To Convert From
To
Multiply by
ppm
lbs/acre
0.3 x sample depth (inches)
ppm
kg/ha
0.1344 x sample depth (cm)
Accuracy Check
Standard Addition Method
a) Snap the neck off a Potassium Voluette Ampule Standard Solution,
250 mg/L.
b) Use the TenSette Pipet to add 0.1, 0.2, and 0.3 mL of standard to
three 25-mL diluted extracts. Mix each thoroughly.
105
POTASSIUM, continued
c) Analyze each standard addition sample as described above. The
potassium concentration should increase 1.0 mg/L, as read on the
spectrophotometer, for each 0.1 mL of standard added.
d) If these increases do not occur, see Standard Additions in Section I
of the DR/2010 Spectrophotometer Procedures Manual for
more information.
Standard Solution Method
Check test accuracy by using a 5.0 mg/L Potassium Standard Solution
listed under Optional Reagents. Or, prepare this solution by diluting
5.00 mL of Potassium Standard Solution, 1000 mg/L to one liter with
demineralized water.
Substitute the standard for the diluted extract and proceed with the test as
described in the procedure. The mg/L K reading should be 5.0 mg/L.
Calibration
A one-time setup of a program for potassium is required. A potassium
program template is pre-programmed into memory to make the process
easier. After the setup is complete, the calibration can be entered for each
new lot of reagents used or as necessary.
Standard Preparation
Prepare standards of 1, 2, 4, 6, and 8 mg/L potassium by diluting 0.1, 0.2,
0.4, 0.6, and 0.8 mL of the contents of the Potassium Voluette Ampule
Standard, 250 mg/L, to 25.0 mL of demineralized water in graduated
mixing cylinders. Use a TenSette Pipet to measure the standard and mix
well. Or, pipet 0.5, 1.0, 2.0, 3.0, and 4.0 mL from Potassium Voluette
Ampule Standards, 500 mg/L, into 250-mL volumetric flasks. Dilute to
volume. Mix well. Transfer 25 mL to each mixing cylinder.
Initial Setup of Potassium Program
Perform a new calibration for each lot of Potassium 3 Reagent Powder
Pillows as follows:
Note: The
templates within
User Program
cannot be run
directly. They
must be copied
into a usable
program number
(greater than 950)
as in step c and d.
Then, calibrate
the program.
a) Press SHIFT USER PRGM. Use the UP arrow key to scroll to Copy
Program. Press ENTER.
b) Scroll to or enter the template number for potassium (905).
Press ENTER.
c) Scroll to or enter the desired user program number for potassium
(>950). Press ENTER. Record the program number for reference.
d) The display will show: Program Copied. Press EXIT. The program
is now ready to be calibrated.
106
POTASSIUM, continued
User Calibration of Potassium Program
a) Use the test procedure to develop color in the standards just before
recording the absorbance values for the calibration.
b) Press SHIFT USER PRGM. Use the UP arrow to scroll to Edit
Program. Press ENTER.
c) Scroll to or enter the program number for potassium (from step c
in Setup). Press ENTER.
d) Use the DOWN arrow to scroll down to Calib Table:X (X denotes a
number which indicates the number of data points in the table).
Press ENTER.
e) The instrument will prompt Zero Sample. Place the blank solution
in the cell holder. Close the light shield. Press ZERO. The
instrument will prompt you to adjust to the proper wavelength if
necessary.
f) The first concentration point will be displayed. Press ENTER to
display the stored absorbance value of the first concentration point.
g) Place the first developed standard solution (same concentration as
the value displayed) in the cell holder. Close the light shield. Press
READ to display the measured absorbance of the standard. Press
ENTER to accept the displayed absorbance value.
h) The second concentration point will be displayed. Press ENTER to
display the stored absorbance value of the second concentration.
Place the second developed standard solution in the cell holder.
Close the light shield. Press READ to display the measured
absorbance value of the standard.
i) Press ENTER to accept the absorbance reading. The next
concentration point will then be displayed.
j) Repeat steps h and i as necessary for the remaining standards.
k) When finished reading the absorbance values of the standards, press
EXIT. Scroll down to Force Zero. Press ENTER to change the setting.
Change to ON by pressing the arrow key, then press ENTER.
l) Scroll down to Calib Formula. Press ENTER twice or until only the
0 in F(0) is flashing. Press the UP arrow to select F3 (cubic
calibration). Press ENTER to select F3.
107
POTASSIUM, continued
Note: Other
calibration fits
may be used if
appropriate.
m) Press EXIT twice. The display will show Store Changes?. Press
ENTER to confirm.
n) Press EXIT. The program is now calibrated and ready for use. Start
with step 2 of the procedure.
Precision
In a single laboratory using a standard solution of 4 mg/L K and one
representative lot of reagent with the DR/2010 Spectrophotometer, a
single operator obtained a standard deviation of ±0.13 mg/L K.
Interferences
The following ions do not interfere below the concentration shown:
Ammonium Nitrogen
15 mg/L as N
Calcium
7000 mg/L as CaCO3
Chloride
15,000 mg/L
Magnesium
6000 mg/L as CaCO3
Summary of Method
Potassium in the sample combines with sodium tetraphenylborate to form
potassium tetraphenylborate, an insoluble white solid. The amount of
turbidity produced is proportional to the potassium concentration.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Alkaline EDTA Solution.................................................. 3 mL ...................... 1 L....... 22687-53
Potassium 2 Reagent Pillows ......................................... 1 pillow.............. 25/pkg....... 14322-98
Potassium 3 Reagent Pillows ......................................... 1 pillow.............. 50/pkg....... 14323-96
REQUIRED APPARATUS
Clippers, for opening powder pillows..................................1 ....................... each........... 968-00
Cylinder, mixing, graduated, 25 mL ....................................1 ....................... each......... 1896-40
Dropper, glass ......................................................................1 ....................... each....... 14197-00
OPTIONAL REAGENTS
Nitric Acid, ACS.......................................................................................500 mL.......... .152-49
Nitric Acid, 1:1 .........................................................................................500 mL......... 2540-49
Potassium Standard Solution, 5 mg/L ......................................................500 mL....... 20583-49
Potassium Standard Solution, 1000 mg/L ................................................100 mL....... 22404-42
Potassium Standard Solution, Voluette Ampule, 250 mg/L, 10 mL.......... 16/pkg....... 14790-10
Potassium Standard Solution, Voluette Ampule, 500 mg/L, 10 mL.......... 16/pkg....... 21093-10
Sodium Hydroxide Solution, 5.0 N ................................................ 59 mL SCDB......... 2450-26
Water, demineralized ....................................................................................... 4 L........... 272-56
108
POTASSIUM, continued
OPTIONAL APPARATUS
Potassium at these levels can be determined directly using the
Potassium Ion Selective Electrode (BNC connector)....................................................50245-00
Description
Unit
Cat. No.
Ampule Breaker Kit .......................................................................................each .......21968-00
Filter Paper, folded, 12.5 cm ....................................................................100/pkg .........1894-57
Flask, volumetric, 250 mL .............................................................................each ...........547-46
Flask, volumetric, 1000 mL ...........................................................................each ...........547-53
Funnel, poly, 65 mm.......................................................................................each .........1083-67
pH Indicator Paper, 1 to 11 pH units....................................................5 rolls/pkg ...........391-33
Pipet Filler, safety bulb...................................................................................each .......14651-00
Pipet, serological, 2 mL..................................................................................each ...........532-36
Pipet, TenSette, 0.1 to 1.0 mL ........................................................................each .......19700-01
Pipet Tips, for TenSette Pipet 19700-01 ....................................................50/pkg .......21856-96
Pipet, volumetric, 0.50 mL, Class A ..............................................................each .......14515-34
Pipet, volumetric, 1.00 mL, Class A ..............................................................each .......14515-35
Pipet, volumetric, 2.00 mL, Class A ..............................................................each .......14515-36
Pipet, volumetric, 3.00 mL, Class A ..............................................................each .......14515-03
Pipet, volumetric, 4.00 mL, Class A ..............................................................each .......14515-04
Pipet, volumetric, 5.00 mL, Class A ..............................................................each .......14515-37
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
109
110
Method 10075
For Soil
SALINITY(CONDUCTIVITY)
Pocket Pal™ Conductivity Tester
Prepare an
Aqueous
soil extract
1. Prepare an Aqueous
2. Prepare the Pocket
3. Immerse the tip of the
4. When the digital
soil extract for
conductivity according
to the procedure given
in the Soil Extraction
Procedures section of
this manual.
Pal Conductivity Tester
according to instructions
following this
procedure. See
Preparation of Pocket
Pal Conductivity Tester.
calibrated Pocket Pal
Conductivity Tester one
inch (2.5 cm) below the
surface of the sample
extract prepared in Step 1
and stir gently until the soil
is completely suspended.
display stabilizes, record
the value. Divide the
value by 10 to determine
mS/cm of conductivity.
Note: If the larger number
displays 199 or greater, the
concentration of salt is greater
Note: The range of the Pocket than the capacity of the meter.
Pal Conductivity Tester is 100- Dilute the suspension by
adding an additional 20 mL of
19,900 mS. To obtain the
demineralized water and
proper value in
multiply the final answer by 2.
µS/cm, multiply the large
reading on the Pocket Pal by Note: See the conversion
the small number (100) in the table following for additional
upper left hand corner of the conversion factors.
display. This gives the
conductivity value in µS/cm.
However, the conductivity of
soils should be expressed in
mS/cm. Simply divide the
large-sized reading by 10
to determine conductivity
in mS/cm.
Note: mS/cm is equal
to dS/m
111
SALINITY(CONDUCTIVITY), continued
5. When testing is
complete, rinse the
electrode with
demineralized water.
Slide the on/off switch to
off. Cover the electrode
with the protective cap
before storing.
Preparation of Pocket Pal Conductivity Tester
a) Add 50 mL of the Saturated Calcium Sulfate Extraction Solution
to a 100 mL beaker.
Note: See Soil Extraction Procedures section of this manual.
b) Slide the on/off switch on top of the Pocket Pal Conductivity
Tester to on. See Figure 1.
Figure 1
Pocket Pal Components
c) Remove the protective cap from the bottom of the instrument.
Immerse the electrode tip one inch below the surface of the Calcium
Sulfate Extraction Solution. Calibrate the instrument by adjusting the
calibration screw near the pocket clip with the trim tool (screwdriver)
provided. Adjust the value to 2200 µS. At 2200 µS, the display will
read 22 with a small 100 in the upper left hand corner. See Figure 2.
112
SALINITY(CONDUCTIVITY), continued
Figure 2
Calibration Trimmer
Conversions
The following table provides equations for converting the conductivity
readings to other units of measure.
From
To
Use this Equation
mS/cm
µS/cm
mS/cm x 1000
µS/cm
mS/cm
µS/cm x 0.001
µS/cm
µmhos/cm
µS/cm x 1
mS/cm
mmhos/cm
mS/cm x 1
µS/cm
mg/L TDS
µS/cm x 0.5
g/L TDS
mg/L TDS
g/L TDS x 1000
mS/cm
g/L TDS
mS/cm x 0.5
mg/L TDS
g/L TDS
mg/L TDS x 0.001
mg/L TDS
gpg TDS
mg/L TDS x 0.05842
g/L TDS
gpg TDS
g/L TDS x 58.42
µS/cm
ohms cm
1,000,000 ÷ µS/cm
mS/cm
ohms cm
1,000 ÷ mS/cm
mS/cm
dS/m
mS/cm x 1.0
113
SALINITY(CONDUCTIVITY), continued
Summary of Method
Electrolytic conductivity is that capacity of ions in a solution to carry
electrical current and is the reciprocal of the solution resistivity. Current is
carried by inorganic dissolved solids (e.g. chloride, nitrate, sulfate, and
phosphate anions and sodium, calcium, magnesium, iron and aluminum
cations). Organic material like oils, phenols, alcohols and sugars do not carry
electrical current well and thus do not have enough conductivity for a useful
estimate of concentration.
Measuring conductivity is done by measuring the resistance occurring in
an area of the test solution defined by the probe’s physical design. Voltage
is applied between the two electrodes immersed in the solution, and the
voltage drop caused by the resistance of the solution is used to calculate
conductivity per centimeter. The basic unit of measure for conductivity is
the Siemen (or mho), the reciprocal of the ohm in the resistance
measurement. Because ranges normally found in aqueous solutions are
small, milliSiemens/cm (10-3 S or mS/cm) and microSiemens/cm (10-6 S
or µS/cm) are used.
REQUIRED REAGENTS AND APPARATUS
Description
Unit
Cat. No.
Beaker, 100 mL............................................................................................................. 22994-42
Battery, optional, 1.4V Zinc-Air .................................................................. 4/pkg....... 23678-00
Pocket Pal Conductivity Tester ..................................................................................... 44375-00
Water, demineralized, 4 L (or equivalent)......................................................................... 272-56
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
114
Method 10074
For Soil
SOLUBLE SALTS (SALINITY)
Saturated Paste Method with Pocket Pal Conductivity Tester
Prepare a
saturated soil
paste extract
1. Prepare a saturated
soil paste extract for
soluble salts according
to the procedure given
in the Soil Extraction
Procedures section of
this manual.
2. Using a dropper,
3. Pour the contents
transfer 2.5 mL of the
into a beaker.
saturated soil extract
into a 50-mL graduated
cylinder. Dilute to the
50-mL mark with
demineralized water and
mix.
115
4. Prepare the Pocket
Pal Conductivity Tester
according to instructions
following this
procedure. See
Preparation of Pocket
Pal Conductivity Tester.
SOLUBLE SALTS (SALINITY), continued
Total salts (meq/L) =
mmhos/cm x 10
5. Immerse the tip of
6. When the digital
the calibrated Pocket Pal
Conductivity Tester one
inch (2.5 cm) below the
surface of the sample
extract prepared in
Step 1 and stir gently.
display stabilizes, record
the value. Multilpy the
mS reading by 2 to get
the electrical
conductivity in
mmhos/cm (mS/cm) of
the saturated extract for
a 2.5 to 50-mL dilution.
Note: The range of the
Pocket Pal Conductivity
Tester is 100-19,900 mS.
To obtain the proper value
in µS/cm, multiply the
large reading on the
Pocket Pal by the small
number (100) in the upper
left hand corner
of the display. This gives
the conductivity value in
µS/cm. However, the
conductivity of soils
should be expressed in
mS/cm. Simply divide the
large-sized reading by 10
to determine conductivity
in mS/cm.
7. To obtain an
Note: If the larger number
displays 199 or greater, the
concentration of salt is greater
than the capacity of the meter.
Dilute the suspension by
adding an additional 20 mL of
demineralized water and
multiply the final answer by 2.
Note: See the conversion
table following for additional
conversion factors.
8. When testing is
estimate of soluble salts, complete, rinse the
multiply the mmhos/cm electrode with
by 10:
demineralized water.
Slide the on/off switch to
Total salts (meq/L) =
mmhos/cm x 10
off. Cover the electrode
with the protective cap
Note: The estimation of
before storing.
soluble salts is based on the
assumption that 10 times
the EC in the range of
0.1 to 2.0 mmhos/cm gives
a value roughly equivalent
in meq/L of the total cation
or anion concentration.
Tolal salts in meq/L may
be converted to
approximate ppm salts
by multiplying by 64.
116
SOLUBLE SALTS (SALINITY), continued
Preparation of Pocket Pal Conductivity Tester
a) Add 50 mL of the Saturated Calcium Sulfate Extraction Solution
to a 100 mL beaker.
Note: See Soil Extraction Procedures section of this manual.
b) Slide the on/off switch on top of the Pocket Pal Conductivity
Tester to on. See Figure 1.
Figure 1
Pocket Pal Components
c) Remove the protective cap from the bottom of the instrument.
Immerse the electrode tip one inch below the surface of the
calcium sulfate extraction solution. Calibrate the instrument by
adjusting the calibration screw near the pocket clip with the trim
tool (screwdriver) provided. Adjust the value to 2200 µS. At
2200 µS, the display will read 22 with a small 100 in the upper left
hand corner. See Figure 2.
Figure 2
Calibration Trimmer
117
SOLUBLE SALTS (SALINITY), continued
Conversions
The following table provides equations for converting the conductivity
readings to other units of measure.
From
To
Use this Equation
mS/cm
µS/cm
mS/cm x 1000
µS/cm
mS/cm
µS/cm x 0.001
µS/cm
µmhos/cm
µS/cm x 1
mS/cm
mmhos/cm
mS/cm x 1
µS/cm
mg/L TDS
µS/cm x 0.5
g/L TDS
mg/L TDS
g/L TDS x 1000
mS/cm
g/L TDS
mS/cm x 0.5
mg/L TDS
g/L TDS
mg/L TDS x 0.001
mg/L TDS
gpg TDS
mg/L TDS x 0.05842
g/L TDS
gpg TDS
g/L TDS x 58.42
µS/cm
ohms cm
1,000,000 ÷ µS/cm
mS/cm
ohms cm
1,000 ÷ mS/cm
mS/cm
dS/m
mS/cm x 1.0
Summary of Method
Measuring the conductivity of the saturated extract is a general method
for estimating soil salinity in relation to plant growth. The method is
somewhat less rapid than a resistance measurement of the soil paste, but
the result is easier to relate to plant response.
This method involves preparing a saturated soil paste by mixing soil and
demineralized water until a characteristic endpoint is reached. The
mixture is filtered to obtain enough extract for the conductivity
measurement. The pH of the soil slurry can be measured by inserting a pH
electrode directly into the slurry.
118
SOLUBLE SALTS (SALINITY), continued
REQUIRED REAGENTS AND APPARATUS
Description
Unit
Cat. No.
Battery, optional, 1.4V, Zinc-Air..................................................................4/pkg .......23678-00
Beaker, poly, 100 mL .....................................................................................each .......22994-42
Cylinder, mixing, 50 mL ................................................................................each .......20886-41
Dropper, glass.................................................................................................each .......14197-05
Pocket Pal Conductivity Tester ......................................................................each .......44375-00
TenSette Pipet, 0.1.0 mL ................................................................................each .......19700-01
Water, demineralized, 4 L (or equivalent) ......................................................each ...........272-56
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
119
120
Method 10084
For Soil
SULFATE (0 to 120 ppm SO42-)
SulfaVer® 4 Method
450 nm
Perform a
CaHPO4 Extraction
1. Prepare a Calcium
Phosphate soil
extraction according to
the procedure in the Soil
Extraction Procedures
section of this manual.
or
Choose Desired
Program Accuracy
??
2. A User-Entered
Calibration is necessary
to obtain the most
accurate results. See
Calibration following
this procedure. Program
680 can be used directly
for applications where a
high degree of accuracy
is not needed.
Note: The nature of
turbidimetric tests and
reagent lot variation
necessitate user calibration
for best results. For more
information about User
Entered Programs, see
Section 3 of the DR/2010
Spectrophotometer
Instrument Manual.
3. Enter the appropriate
stored program number
for sulfate (SO42-)
powder pillows.
Press: 6 8 0 ENTER
or
9 ? ? ENTER
The display will show:
Dial nm to 450
Note: The Pour-Thru
cell may be used with this
procedure. Rinse with
demineralized water
immediately after each
measurement.
121
4. Rotate the wavelength
dial until the small
display shows:
450 nm
When the correct
wavelength is dialed in
the display will quickly
show: Zero Sample
then:
mg/L SO42Note: For greater
accuracy, perform a user
calibration for each new lot
of SulfaVer 4 Sulfate
Reagent Powder Pillows;
see User Calibration
following this procedure.
SULFATE, continued
5. Fill a clean sample
cell with 25 mL
of filtered extract.
Note: Filter highly turbid
or colored samples. Use
filtered sample in this step
and Step 7.
6. Add the contents of
one SulfaVer 4 Sulfate
Reagent Powder Pillow
to the sample cell (the
prepared sample). Swirl
to dissolve.
7. Press: SHIFT TIMER
A 5-minute reaction
period will begin.
Allow the cell to
stand undisturbed.
8. When the timer
beeps, the display will
show: mg/L SO42Fill a second sample cell
with 25 mL of filtered
extract (the blank).
A white turbidity
will develop if sulfate
is present.
Accuracy is not affected
by undissolved powder.
9. Place the blank into 10. Press: ZERO
the cell holder. Close the
The display will show:
light shield.
Zeroing. . .
then:
0. mg/L
11. Within five minutes 12. Press: READ
after the timer beeps,
place the prepared
sample into the cell
holder. Close the light
shield.
SO42-
The display will show:
Reading. . .
then the results in mg/L
SO42- will be displayed.
Note: Clean the sample cells
with soap and a brush.
122
SULFATE, continued
13. Multiply the result
by 2 and record results
as ppm SO42-.
Note: Divide result by 3 to
obtain result as ppm S. For
other units, see Table 1.
Table 1 Conversion Factors
To Convert
From
To
ppm
lbs/acre
0.3 x sample depth (inches)
ppm
kg/ha
0.1344 x sample depth (cm)
Multiply by
Accuracy Check
Standard Additions Method
a) Fill three 25-mL graduated mixing cylinders with 25 mL of
filtered extract.
b) Snap the neck off a Sulfate Voluette Ampule Standard Solution,
2500 mg/L SO42- .
c) Use a TenSette Pipet to add 0.1, 0.2 and 0.3 mL of standard to the
three 25-mL diluted extracts. Mix thoroughly.
d) Analyze each sample as described above. The sulfate
concentration should increase 10 mg/L, as read on the
spectrophotometer in step 11, for each 0.1 mL of standard added.
e) If these increases do not occur, see Standard Additions in
Section I of the DR/2010 Spectrophotometer Procedures
Manual for more information.
Standard Solution Method
Check the accuracy of the test by using the Sulfate Standard Solution,
50 mg/L, listed under Optional Reagents. Or, prepare this solution by
pipetting 1.0 mL of the contents of a Voluette Ampule Standard for
Sulfate (2500 mg/L) into a 50-mL volumetric flask. Dilute to volume
with demineralized water.
Substitute this standard for the diluted extract and proceed with the test as
described in the procedure. The mg/L SO42- reading should be 50 mg/L in
Step 11.
123
SULFATE, continued
Calibration
For most accurate results, the use of a user-calibrated program is highly
recommended. The Hach stored program 680 is intended for applications
where a high degree of accuracy is not necessary.
A one-time setup program for sulfate is required. A sulfate program
template is pre-programmed into memory to make the process easier.
After the setup is complete, the calibration can be entered for each new lot
of reagents used or as necessary.
Standard Preparation
A new calibration should be performed for each new lot of SulfaVer 4
Sulfate Reagent as follows:
Prepare standards of 10, 20, 30, 40, 50, and 60 mg/L sulfate by pipetting
1, 2, 3, 4, 5, and 6 mL of a 1000-mg/L Sulfate Standard Solution into
100-mL volumetric flasks. Dilute to the mark with demineralized water.
Mix well.
Initial Setup of Sulfate Program
Note: The
a) Press SHIFT USER PRGM. Use the UP arrow key to scroll to Copy
templates within
Program. Press ENTER.
User Program
cannot be run
directly. They
must be copied
into a usable
program number
(greater than 950)
as in step c and d.
Then, calibrate
the program.
The 680
preprogrammed
calibration may
be suitable for
applications
where a high
degree of
accuracy is
not necessary.
b) Scroll to or enter the template number for sulfate [906]. Press ENTER.
c) Scroll to or enter the desired user program number for sulfate
(>950). Press ENTER. Record the program number for reference.
d) The display will show: Program Copied. Press EXIT. The program
is now ready to be calibrated.
124
SULFATE, continued
User Calibration of Sulfate Program
a) Use the test procedure to develop color in the standards just before
recording the absorbance values for the calibration.
b) Press SHIFT USER PRGM. Use the UP arrow to scroll to Edit
Program. Press ENTER.
c) Scroll to or enter the program number for sulfate (from step c in
Setup). Press ENTER.
d) Use the DOWN arrow to scroll down to Calib Table:X (X= denotes a
number which indicates the number of data points in the table).
Press ENTER.
e) The instrument will prompt Zero Sample. Place the blank solution
in the cell holder. Close the light shield. Press ZERO. The
instrument will prompt you to adjust to the proper wavelength if
necessary.
f) The first concentration point will be displayed. Press ENTER to
display the stored absorbance value of the first concentration point.
g) Place the first developed standard solution (same concentration as
the value displayed) in the cell holder. Close the light shield. Press
READ to display the measured absorbance of the standard. Press
ENTER to accept the displayed absorbance value.
h) The second concentration point will be displayed. Press ENTER to
display the stored absorbance value of the second concentration.
Place the second developed standard solution in the cell holder.
Close the light shield. Press READ to display the measured
absorbance value of the standard.
i) Press ENTER to accept the absorbance reading. The next
concentration point will then be displayed.
j) Repeat steps h and i as necessary for the remaining standards.
k) When finished reading the absorbance values of the standards, press
EXIT. Scroll down to Force Zero. Press ENTER to change the setting.
Change to ON by pressing the arrow key, then press ENTER.
l) Scroll down to Calib Formula. Press ENTER twice or until only the
0 in F(0) is flashing. Press the DOWN arrow to select F3 (cubic
calibration). Press ENTER to select F3.
125
SULFATE, continued
Note: Alternative
calibration fits
may also be used
if appropriate.
m) Press EXIT twice. The display will show Store Changes?. Press
ENTER to confirm.
n) Press EXIT. The program is now calibrated and ready for use. Start
with step 2 of the iconed test procedure.
Precision
In a single laboratory, using a standard solution of 50 mg/L sulfate and
two representative lots of powder pillows with the DR/2010
Spectrophotometer, a single operator obtained a standard deviation of
±0.9 mg/L sulfate.
Estimated Detection Limit (EDL)
The EDL for program 680 is 7 mg/L SO4-. The EDL is the calculated
lowest average concentration in a demineralized water matrix that is
different from zero with a 99% level of confidence. For more information
on derivation and use of Hach’s estimated detection limit, see Section I of
the DR/2010 Spectrophotometer Procedures Manual.
Interferences
The following interfere at levels above those concentrations listed:
Calcium
20,000 mg/L as CaCO3
Chloride
40,000 mg/L as Cl-
Magnesium
10,000 mg/L as CaCO3
Silica
500 mg/L as CaCO3
Summary Of Method
Soluble sulfate, plus a faction of absorbed sulfate, is extracted with a
solution of CaHPO4 (500 mg/L P). Phospate ions displace the absorbed
sulfate, and calcium ions depress the extraction of soil organic matter,
eliminating contamination from the extractable organic sulfur. Activated
decolorizing charcoal is slurried with the extracting solution to give a
clear, colorless extract.
Sulfate ions in the sample react with barium in the SulfaVer 4 Sulfate
Reagent and form insoluble barium sulfate turbidity. The amount of
turbidity formed is proportional to the sulfate concentration.
126
SULFATE, continued
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Units
Cat. No.
SulfaVer 4 Sulfate Reagent Powder Pillows ..................1 pillow ..............50/pkg .......12065-99
REQUIRED APPARATUS
Sample Cell, 25 mL, matched pair...................................... 2........................each .......20950-00
Brush ................................................................................... 1........................each ...........690-00
OPTIONAL REAGENTS
Sulfate Standard Solution, 50 mg/L ......................................................... 500 mL .........2578-49
Sulfate Standard Solution, 1000 mg/L ..................................................... 500 mL .......21757-49
Sulfate Standard Solution, Voluette Ampule, 2500 mg/L, 10 mL .............16/pkg .......14252-10
Water, demineralized ........................................................................................4 L ...........272-56
OPTIONAL APPARATUS
Ampule Breaker Kit .......................................................................................each .......21968-00
Cylinder, Graduated Mixing, 25 mL ..............................................................each .......20886-40
Filter Paper, folded, 12.5 cm ....................................................................100/pkg .........1894-57
Flask, volumetric, 50 mL, Class A.................................................................each .......14574-41
Flask, volumetric, 100 mL, Class A...............................................................each .......14574-42
Funnel, poly, 65 mm.......................................................................................each .........1083-67
Pipet, TenSette, 0.1 to 1.0 mL ........................................................................each .......19700-01
Pipet Tips, for 19700-01 Pipet ...................................................................50/pkg .......21856-96
Pipet, volumetric, 1.00 mL, Class A ..............................................................each .......14515-35
Pipet, Volumetric, 2.00 mL, Class A............................................................. each .......14515-36
Pipet, Volumetric, 3.00 mL, Class A............................................................. each .......14515-03
Pipet, Volumetric, 4.00 mL, Class A............................................................. each .......14515-04
Pipet, Volumetric, 5.00 mL, Class A............................................................. each .......14515-37
Pipet, Volumetric, 6.00 mL, Class A............................................................. each .......14515-06
Pipet Filler, safety bulb...................................................................................each .......14651-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
127
128
Method 10082
For Soil
SULFUR REQUIREMENT
Titrimetric Sulfuric Acid Method
5 to 10
minutes
FIL
L
LIN
E
Prepare
Soil Sample
1. Prepare the soil
2. Weigh 10.0 g of
3. Add 100 mL of
4. Place a stir bar in the
samples according
to the instruction
in Section 2 Sample
Collection and
Preparation of
this manual.
soil. Pour into a
250-mL beaker.
demineralized water to
the beaker.
beaker and place the
beaker on a magnetic
stirrer. Stir 5-10 minutes.
Note: Two 5-gram scoops
may be used to measure
10.0 g of soil.
5. Immerse the pH
6. Insert a clean delivery
electrode in the soil-water tube into an 8.00 N
slurry (continue stirring). Sulfuric Acid Titration
Cartridge. Attach the
cartridge to the titrator
body. See General
Description, Step-byStep, of the Digital
Titrator Manual for
assembly instructions,
if necessary.
7. Attach the cartridge to 8. Immerse the delivery
the Digital Titrator and
turn the delivery knob
until all the air is expelled
and titrant appears. Wipe
the tip and reset the
counter to zero.
129
tube tip into the slurry
and begin titrating.
Titrate until the pH
meter reads pH 7.6.
Note: The 7.6 end point is
appropriate for many soils.
Specific circumstances may
require a different pH.
SULFUR REQUIREMENT, continued
9. Continue stirring for 10. Multiply the digits
5 more minutes. If the
pH rises during this
time, add more titrant to
keep the pH at 7.6.
Record the total number
of digits used.
required by 64 to obtain
the sulfur requirement in
lbs/acre foot.
Note: The factor 64 is
derived from a calibration
value of 800 digits/mL for
the Digital Titrator, an
equivalent weight of
16 for sulfur, and a value
of 4 million pounds for an
acre foot of soil.
Note: To convert lbs/acre
foot to kg/ha, multiply
by 1.10.
Summary of Method
Nutrient deficiencies in crops frequently occur in alkaline soils. The high
pH of these soils decreases the solubility of essential minerals and makes
them unavailable for plant uptake. One method of improving the fertility
of alkaline soils is adding ammonium sulfate, sulfuric acid or elemental
sulfur. These compounds lower the soil pH and increase mineral solubility
and availability for plants.
Hach’s Digital Titrator Method for sulfur requirement uses a sulfuric acid
titration with an end point of pH 7.6. The sulfur requirement is calculated
in lbs/acre based on the results of the titration.
130
SULFUR REQUIREMENT, continued
REQUIRED REAGENTS
Description
Cat. No.
Sulfuric Acid Titration Cartridge, 8.00 N .....................................................................14391-01
REQUIRED APPARATUS
Balance, AccuLab Pocket Pro 150B .............................................................................25568-00
Beaker, 250 mL .................................................................................................................500-46
Cylinder, graduated, 100 mL.............................................................................................508-42
Digital Titrator...............................................................................................................16900-00
EC10 Portable pH Meter with Hach One Electrode .....................................................50050-10
or
EC30 Benchtop pH Meter with Hach One Electrode,
(115 V North American) ...............................................................................................50100-10
(230 V Continental/European) ......................................................................................50100-11
or
EC40 Benchtop pH/ISE Meter with Hach One Electrode,
(115 V North American) ...............................................................................................50125-10
(230 V Continental/European) ......................................................................................50125-11
Scoopula, stainless steel ................................................................................................12257-00
Soil Scoop, 5g ...............................................................................................................26572-05
Stir Bar, Teflon ..............................................................................................................45315-00
Stir Plate/Electrode Stand, 115 V..................................................................................45300-01
Stir Plate/Electrode Stand, 230 V..................................................................................45300-02
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
131
132
SECTION 5
SOIL TEXTURE ESTIMATION
Routine soil analysis usually includes an estimation of soil texture. This
method is used when exact proportions of sand, silt, and clay are not
needed or when equipment for mechanical analysis is not available. While
soil texture estimation requires practice to become highly proficient,
satisfactory results can be obtained by using the technique diagrammed
on the next page and by referring to the modified textural triangle below.
The procedure for estimating soil texture was developed at Kansas State
University by Dr. David Whitney.
The modified version of the textural diagram below omits the rare silt
class and combines the loamy sand class with the sandy loam class. Other
class boundaries are arranged in a symmetrical fashion that should be
easily visualized and remembered.
The modified triangle consists of three tiers based on clay content:
1. CLAYS — those soils high in clay content are strongly cohesive and
capable of being shaped into good ribbons.
2. CLAY LOAMS — are intermediate in clay content, cohesiveness, and
ribbon formation.
3. LOAMS — or soils low enough in clay content so they exhibit little or
no cohesiveness and form poor or weak ribbons. The SANDS do not
form ribbons.
The three tiers are each subdivided into three classes (see Figure 1 and
Figure 2):
a) If silt is highly prominent, the prefix “silt” or “silty” is added to
form categories on the left side of the triangle.
b) If sand is prominent, the prefix “sandy” is added to form the
categories on the right side of the triangle.
c) When neither silt nor sand predominates, the intermediate
category is used without a prefix, as illustrated by the central
portion of the triangle.
133
SOIL TEXTURE ESTIMATION, continued
Figure 1
Diagram for Estimating
Soil Texture
134
SOIL TEXTURE ESTIMATION, continued
Figure 2
Flow Diagram for Estimating
Soil Texture
135
136
TOTAL EXCHANGEABLE ACIDITY
Method 10083
For Soil
NaOH with a Digital Titrator
Prepare a KCI
Extraction
1. Prepare a potassium
chloride soil extract
according to the
procedure in the Soil
Extraction Procedures
section of this manual.
Leave the extract in the
250-mL erlenmeyer
flask to perform this test.
2. Add the contents of
3. Insert a clean delivery
one Phenolphthalein
tube into a 1.600 N
Indicator Powder Pillow Sodium Hydroxide
to the flask. Swirl to mix. Titration Cartridge.
Attach the cartridge to the
Note: Four drops of
Phenolphthalein Indicator Digital Titrator body. See
Solution may be substituted General Description,
Step-by-step, of the
for the powder.
Digital Titrator Manual
for assembly instructions.
Note: For samples with low
Total Exchangeable Acidity
(0 - 160 mg/L CaCO3) use a
0.1600 N Sodium Hydroxide
Titration Cartridge.
137
4. Hold the Digital
Titrator with the
cartridge tip pointing up.
Turn the delivery knob
to eject air and a few
drops of titrant. Reset
the counter to zero and
wipe the tip.
Note: For added
convenience use the
TitraStir® Stirring
Apparatus, see General
Description, Step 3 in
Step-by-Step, of the Digital
Titrator Manual.
TOTAL EXCHANGEABLE ACIDITY, continued
Digits Required ÷ 25
= meq/100 g Total
Exchangeable
Acidity
5. Titrate with sodium
6. Calculate:
hydroxide from colorless
to a light pink color that
persists for 30 seconds.
Record the number of
digits required.
Digits Required ÷ 25
= meq/100 g Total
Exchangeable Acidity
Note: A solution of one pH
8.3 Buffer Powder Pillow and
one Phenolphthalein Powder
Pillow in 50 mL of
demineralized water is
recommended as a
comparison for determining
the proper end point.
Calculating Lime Requirement
One meq per 100 g of total exchangeable acidity (TEA) requires 1000 pounds
of 100% CCE calcium carbonate:
Lime Requirement (tons/AFS*) = TEA
----------2
Lime Requirement (metric tons/ha) = TEA x 1.12
*AFS = Acre furrow slice
Accuracy Check
To verify analytical technique or if interferences are suspected, perform
the following accuracy check.
a) Snap the neck off an Acidity Voluette Ampule Standard, 0.500 N.
b) Use a TenSette Pipet to add 0.1 mL of standard to the sample
titrated in Step 5 for phenolphthalein acidity. Resume titration
back to the same end point. Record the number of digits required.
c) Repeat, using two more additions of 0.1 mL. Titrate to the end
point after each addition.
138
TOTAL EXCHANGEABLE ACIDITY, continued
d) Each 0.1 mL addition of standard should require 25 additional
digits of 1.600 N titrant or 250 digits of 0.1600 N titrant. If these
uniform increases do not occur, refer to Section I, Standard
Addition, of the DR/2010 Spectrophotometer Procedures Manual.
Summary of Method
Sodium hydroxide is used to titrate the sample to a phenolphthalein
colorimetric endpoint. The pH 8.3 end point includes weaker acid species
and represents the total acidity.
REQUIRED REAGENTS
Quantity Required
Per Test
Description
Unit
Cat. No.
Phenolphthalein Powder Pillows....................................1 pillow ............100/pkg ...........942-99
Water, demineralized ....................................................... varies ......................4 L ...........272-56
Select one or both based on range:
Sodium Hydroxide Titration Cartridge, 1.600 N ...........................................each .......14379-01
Sodium Hydroxide Titration Cartridge, 0.1600 N .........................................each .......14377-01
REQUIRED APPARATUS
Clippers, for opening powder pillows ................................. 1........................each ...........968-00
Digital Titrator..................................................................... 1........................each .......16900-01
Flask, erlenmeyer, 250 mL.................................................. 1........................each ...........505-46
Select one or more based on sample volume
Cylinder, graduated, 10 mL............................................................................each ...........508-38
Cylinder, graduated, 25 mL............................................................................each ...........508-40
Cylinder, graduated, 50 mL............................................................................each ...........508-41
Cylinder, graduated, 100 mL..........................................................................each ...........508-42
OPTIONAL REAGENTS
Acidity Voluette Ampule Standard, 0.500 N H2SO4, 10 mL......................16/pkg .......14330-10
Buffer Powder Pillows, pH 3.7...................................................................25/pkg .......14551-68
Buffer Powder Pillows, pH 8.3...................................................................25/pkg ...........898-68
Hydrogen Peroxide Solution, 30%........................................................... 200 mL ...........144-45
Phenolphthalein Indicator Solution, 5 g/L, ACS............................ 100 mL MDB ...........162-32
Sodium Thiosulfate Standard Solution, 01.N................................. 100 mL MDB ...........323-32
139
TOTAL EXCHANGEABLE ACIDITY, continued
OPTIONAL APPARATUS
Description
Unit
Cat. No.
Bottle, wash, poly, 500 mL ............................................................................ each........... 620-11
Clamp, extension ........................................................................................... each....... 21145-00
Clamp Holder................................................................................................. each........... 326-00
Demineralizer Assembly, 473 mL ................................................................. each....... 21846-00
Delivery Tubes, straight, for Digital Titrator ............................................... 5/pkg....... 17205-00
Hot Plate, 4-inch, circular .............................................................................. each....... 12067-01
pH electrode, Hach One Combination with Temp......................................... each....... 48600-22
pH meter, EC 10 Portable .............................................................................. each....... 50050-60
Pipet, TenSette, 0.1 to 1.0 mL........................................................................ each....... 19700-01
Pipet Tips, for 19700-01 TenSette Pipet .................................................... 50/pkg....... 21856-96
Pipet, volumetric, Class A, 10 mL................................................................. each....... 14515-38
Pipet, volumetric, Class A, 20 mL................................................................. each....... 14515-20
Pipet, volumetric, Class A, 25 mL................................................................. each....... 14515-40
Pipet Filler, safety bulb .................................................................................. each....... 14651-00
Stir Bar Retriever, 45.7 cm (12 inches) long ................................................. each....... 15232-00
Support Stand................................................................................................. each........... 563-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
140
SECTION 6
IRRIGATION WATER PROCEDURES
141
142
ALKALINITY (10 - 4000 mg/L as CaCO3)
Method 8203
For water, wastewater and seawater
Phenolphthalein and Total
Using Sulfuric Acid with a Digital Titrator
1. Select the sample
2. Insert a clean delivery 3. Turn the delivery knob 4. Use a graduated
volume and Sulfuric
Acid (H2SO4) Titration
Cartridge corresponding
to the expected
alkalinity concentration
as mg/L calcium
carbonate (CaCO3) from
Table 1.
tube into the titration
cartridge. Attach the
cartridge to the titrator
body. See General
Description, Step-byStep, of the Digital
Titrator Manual for
assembly instructions,
if necessary.
Note: See Sampling and
Storage following
these steps.
to eject a few drops of
titrant. Reset the counter
to zero and wipe the tip.
cylinder or pipet to
measure the sample
volume from Table 1.
Transfer the sample into a
Note: For added
clean 250-mL erlenmeyer
convenience use the
flask. Dilute to about the
®
TitraStir Stirring
100-mL mark with
Apparatus, see General
demineralized water,
Description, Step 3 in
Step-by-Step, of the Digital if necessary.
Titrator Manual.
Table 1
Range
(mg/L as CaCO3)
Sample
Volume (mL)
Titration
Cartridge
(H2SO4)
Catalog
Number
Digit
Multiplier
10-40
40-160
100-400
200-800
500-2000
1000-4000
100
25
100
50
20
10
0.1600
0.1600
1.600
1.600
1.600
1.600
14388-01
14388-01
14389-01
14389-01
14389-01
14389-01
0.1
0.4
1.0
2.0
5.0
10.0
143
ALKALINITY, continued
6. If the solution turns
7. Calculate:
pink, titrate to a
Digits Required x
colorless end point.
Digit Multiplier =
Place the delivery tube
mg/L CaCO3 P Alkalinity
tip into the solution and
Note: A solution of one pH
swirl the flask while
8.3 Buffer Powder Pillow
titrating with sulfuric
and one Phenolphthalein
Powder Pillow in 50 mL of acid. Record the number
of digits required.
demineralized water is
5. Add the contents of
one Phenolphthalein
Indicator Powder Pillow
and swirl to mix.
recommended as a
comparison for
determining the proper
end-point color.
Note: Four drops of
Phenolphthalein Indicator
Solution may be substituted
for the Phenolphthalein
Indicator Powder Pillow.
Note: If the solution is
colorless before titrating
with sulfuric acid, the
Phenolphthalein (P)
alkalinity is zero; proceed
with Step 8.
144
8. Add the contents of
one Bromcresol GreenMethyl Red Indicator
Powder Pillow to the
flask and swirl to mix.
Note: Four drops of Methyl
Purple Indicator Solution
may be substituted for the
Bromcresol Green-Methyl
Red Indicator Powder
Pillow. Titrate from green to
a gray end point (pH 5.1).
Note: Four drops of
Bromcresol Green-Methyl
Red Indicator Solution may
be substituted for the
Bromcresol Green-Methyl
Red Indicator Powder Pillow.
ALKALINITY, continued
9. Continue the titration
with sulfuric acid to a
light greenish blue-gray
(pH 5.1), a light violetgray (pH 4.8), or a light
pink (pH 4.5) color, as
required by the sample
composition; see Table 2.
Record the number of
digits required.
10. Calculate:
Total Digits Required x Digit
Multiplier =
mg/L as CaCO3 Total
(T or M) Alkalinity
Note: Carbonate,
bicarbonate and hydroxide
concentrations may be
expressed individually using
the relationships shown in
Table 3 on page 147.
Note: A solution of one
Bromcresol Green-Methyl
Red Powder Pillow and one Note: meq/L Alkalinity =
pillow of the appropriate pH mg/L as CaCO3 ÷ 50.
buffer in 50 mL of
demineralized water is
recommended as a
comparison for judging the
proper end-point color. If
the pH 3.7 end point is used,
use a Bromphenol Blue
Powder Pillow instead of a
Bromcresol Green-Methyl
Red and titrate to a green
end point.
Table 2
Sample Composition
End
Point
Alkalinity about 30 mg/L
Alkalinity about 150 mg/L
Alkalinity about 500 mg/L
Silicates or Phosphates present
Industrial waste or complex system
pH 5.1
pH 4.8
pH 4.5
pH 4.5
pH 3.7
145
ALKALINITY, continued
Sampling and Storage
Collect samples in clean plastic or glass bottles. Fill completely and cap
tightly. Avoid excessive agitation or prolonged exposure to air. Samples
should be analyzed as soon as possible after collection but can be stored at
least 24 hours by cooling to 4 oC (39 oF) or below. Warm to room
temperature before analyzing.
Alkalinity Relationship Table
Total alkalinity primarily includes hydroxide, carbonate and bicarbonate
alkalinities. The concentration of these alkalinities in a sample may be
determined when the phenolphthalein and total alkalinities are known
(see Table 3).
Table 3 Alkalinity Relationship
Hydroxide
Alkalinity
is equal to:
Carbonate Alkalinity
is equal to:
Phenolphthalein
Alkalinity = 0
0
0
Equal to Total
Alkalinity
Phenolphthalein
Alkalinity equal to Total
Alkalinity
Total Alkalinity
0
0
2
0
3
Phenolphthalein
Alkalinity less than one
half of Total
Alkalinity
2 times the
Phenolphthalein
Alkalinity
Total Alkalinity minus
two times
Phenolphthalein
Alkalinity
Phenolphthalein
Alkalinity equal to one
half of Total Alkalinity
0
2 times the
Phenolphthalein
Alkalinity
0
4
Phenolphthalein
Alkalinity greater than
one half of Total
Alkalinity
2 times the
Phenolphthalein
minus Total
Alkalinity
2 times the
difference between
Total and
Phenolphthalein
Alkalinity
0
Row
Result of Titration
1
5
Bicarbonate
Alkalinity
is equal to:
To use the table follow these steps:
a) Does the phenolphthalein alkalinity equal zero? If yes, use Row 1.
b) Does the phenolphthalein alkalinity equal total alkalinity? If yes,
use Row 2.
c) Multiply the phenolphthalein alkalinity by 2.
146
ALKALINITY, continued
d) Select Row 3, 4, or 5 based on comparing the result of Step c with
the total alkalinity.
e) Perform the required calculations in the appropriate row, if any.
f) Check your results. The sum of the three alkalinity types will equal
the total alkalinity.
For example:
A sample has 170 mg/L as CaCO3 phenolphthalein alkalinity and 250 mg/L
as CaCO3 total alkalinity. What is the concentration of hydroxide, carbonate
and bicarbonate alkalinities?
The phenolphthalein alkalinity does not equal 0 (it is 170 mg/L), see Step a.
The phenolphthalein alkalinity does not equal total alkalinity (170 mg/L
vs 250 mg/L), see Step b.
The phenolphthalein alkalinity multiplied by 2 = 340 mg/L, see Step c.
Because 340 mg/L is greater than 250 mg/L, select Row 5. see Step d.
The hydroxide alkalinity is equal to: (See Step e)
340 – 250 = 90 mg/L hydroxide alkalinity
The carbonate alkalinity is equal to:
250 – 170 = 80
80 × 2 = 160 mg/L carbonate alkalinity
The bicarbonate alkalinity equals 0 mg/L.
Check: (See Step f)
90 mg/L hydroxide alkalinity + 160 mg/L carbonate alkalinity
+ 0 mg/L bicarbonate alkalinity = 250 mg/L
The above answer is correct; the sum of each type equals the total alkalinity.
Accuracy Check
Standard Additions Method
This accuracy check should be performed when interferences are suspected or
to verify analytical technique.
1. Snap the neck off an Alkalinity Voluette Ampule Standard, 0.500 N.
2. Use a TenSette Pipet to add 0.1 mL of standard to the sample titrated in
Steps 6 or 9. Resume titration back to the same end point. Record the
number of digits needed.
147
ALKALINITY, continued
3. Repeat, using two more additions of 0.1 mL. Titrate to the end point
after each addition.
4. Each 0.1 mL addition of standard should require 25 additional digits of
1.600 N titrant or 250 digits of 0.1600 N titrant. If these uniform increases
do not occur, refer to Appendix A, Accuracy Check and Standard
Additions in the Digital Titrator Manual to determine the cause.
Interferences
• Highly colored or turbid samples may mask the color change at the
end point. Use a pH meter for these samples.
• Chlorine may interfere with the indicators. Add one drop of 0.1 N
Sodium Thiosulfate to eliminate this interference.
Summary of Method
The sample is titrated with sulfuric acid to a colorimetric end point
corresponding to a specific pH. Phenolphthalein alkalinity is determined by
titration to a pH of 8.3, as evidenced by the color change of phenolphthalein
indicator, and indicates the total hydroxide and one half the carbonate present.
M (methyl orange) or T (total) alkalinity is determined by titration to a pH
between 3.7 and 5.1, and includes all carbonate, bicarbonate and hydroxide.
REQUIRED REAGENTS
(varies with sample characteristics)
Alkalinity Reagent Set (about 100 tests)
Includes: (1) 943-99, (1) 942-99, (1) 14389-01, (1) 14388-01, .............................. 22719-00
Description
Unit
Cat. No
Bromcresol Green-Methyl Red Powder Pillows...................................... 100/pkg........... 943-99
Phenolphthalein Powder Pillows ............................................................. 100/pkg........... 942-99
Water, demineralized ....................................................................................... 4 L ........... 272-56
Sulfuric Acid Titration Cartridge, 1.600 N .................................................... each....... 14389-01
Sulfuric Acid Titration Cartridge, 0.1600 N .................................................. each....... 14388-01
REQUIRED APPARATUS
Clippers, for opening pillows......................................................................... each........... 968-00
Digital Titrator ............................................................................................... each....... 16900-01
Flask, erlenmeyer, 250 mL ............................................................................ each........... 505-46
Select one or more based on sample concentration
Cylinder, graduated, 10 mL ........................................................................... each........... 508-38
Cylinder, graduated, 25 mL ........................................................................... each........... 508-40
Cylinder, graduated, 50 mL ........................................................................... each........... 508-41
Cylinder, graduated, 100 mL ......................................................................... each........... 508-42
148
ALKALINITY, continued
OPTIONAL REAGENTS
Description
Unit
Cat. No
Alkalinity Standard Solution,
Voluette Ampule 0.500 N Na2CO3, 10 mL .............................................16/pkg .......14278-10
Bromcresol Green-Methyl Red Indicator Solution ........................ 100 mL MDB .......23292-32
Bromphenol Blue Indicator Solution ............................................. 100 mL MDB .......14552-32
Bromphenol Blue Powder Pillows ...........................................................100/pkg .......14550-99
Buffer Powder Pillows, pH 3.7...................................................................25/pkg .......14551-68
Buffer Powder Pillows, pH 4.5...................................................................25/pkg ...........895-68
Buffer Powder Pillows, pH 4.8...................................................................25/pkg ...........896-68
Buffer Powder Pillows, pH 5.1...................................................................25/pkg ...........897-68
Buffer Powder Pillows, pH 8.3...................................................................25/pkg ...........898-68
Methyl Purple Indicator Solution................................................... 100 mL MDB .......21934-32
Phenolphthalein Indicator Solution, 5 g/L ....................................100 mL MDB* ...........162-32
Sodium Thiosulfate Standard Solution, 0.1 N................................ 100 mL MDB ...........323-32
OPTIONAL APPARATUS
Bottle, wash, poly, 500 mL ............................................................................each ...........620-11
Clamp, 2-prong extension, 38 mm .................................................................each .......21145-00
Clamp Holder .................................................................................................each ...........326-00
Demineralizer Assembly, 473 mL..................................................................each .......21846-00
Delivery Tubes, with 180° hook...................................................................5/pkg .......17205-00
Delivery Tubes, 90° with hook for TitraStir.................................................5/pkg .......41578-00
Hach One Combination pH Electrode with Temp .........................................each .......48600-22
pH Meter, EC10, portable ..............................................................................each .......50050-60
Pipet, TenSette, 0.1 to 1.0 mL ........................................................................each .......19700-01
Pipet tips for 19700-01 TenSette pipet .......................................................50/pkg .......21856-96
Pipet, volumetric, Class A, 10 mL .................................................................each .......14515-38
Pipet, volumetric, Class A, 20 mL .................................................................each .......14515-20
Pipet, volumetric, Class A, 25 mL .................................................................each .......14515-40
Pipet, volumetric, Class A, 50 mL .................................................................each .......14515-41
Pipet, volumetric, Class A, 100 mL ...............................................................each .......14515-42
Pipet Filler, safety bulb...................................................................................each .......14651-00
Stand, Stirrer/Electrode holder, 115 Vac ........................................................each .......45300-01
Stand, Stirrer/Electrode holder, 230Vac .........................................................each .......45300-02
Support ring stand ..........................................................................................each ...........563-00
TitraStir Mixer/Stand Assembly, 115 Vac......................................................each .......19400-00
TitraStir Mixer/Stand, Assembly, 230 Vac.....................................................each .......19400-10
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
* Contact Hach for larger sizes.
149
150
CHLORIDE
Method 8207
For water, wastewater, and seawater
(10 - 10,000 mg/L as Cl-)
Using Silver Nitrate with a Digital Titrator
1. Select the sample
2. Insert a clean
volume and Silver
Nitrate Titration
Cartridge corresponding
to the expected chloride
concentration from
Table 1.
delivery tube into the
titration cartridge. Attach
the cartridge to the titrator
body. See General
Description Section,
Step-by-Step, of the
Digital Titrator Manual
for assembly instructions,
if necessary.
3. Turn the delivery
knob to eject a few drops
of titrant. Reset the
counter to zero and wipe
the tip.
4. Use a graduated
cylinder or pipet to
measure the sample
volume from Table 1.
Transfer the sample
into a clean 250-mL
Note: For added
erlenmeyer flask.
convenience use the
Dilute to about the
®
TitraStir Stirring
100-mL mark with
Apparatus, see General
demineralized water, if
Description, Step 3 in
Step-by-Step, of the Digital necessary.
Titrator Manual.
Note: See Sampling and
Storage following
these steps.
Table 1
Range
(mg/L as
Cl-)
10-40
25-100
100-400
250-1000
1000-4000
2500-10000
Sample
Volume
(mL)
Titration
Cartridge
(N AgNO3)
Catalog
Number
Digit
Multiplier
100
40
50
20
5
2
0.2256
0.2256
1.128
1.128
1.128
1.128
14396-01
14396-01
14397-01
14397-01
14397-01
14397-01
0.1
0.25
1.0
2.5
10.0
25.0
151
CHLORIDE, continued
5. Add the contents of
one Chloride 2 Indicator
Powder Pillow and swirl
to mix.
6. Place the delivery
7. Calculate:
tube tip into the solution
and swirl the flask while
titrating with silver
nitrate from a yellow to
Note: Results will still be
red-brown color.
accurate if a small
amount of the powder does Record the number of
digits required.
not dissolve.
Digits Required x
Digit Multiplier =
mg/L Chloride
Note: Results may be
expressed as mg/L sodium
chloride by multiplying the
mg/L chloride by 1.65.
Note: meq/L Chloride =
mg/L Chloride ÷ 35.45.
Sampling and Storage
Collect at least 100 to 200 mL of sample in a clean glass or polyethylene
container. Samples may be stored up to 7 days before analysis.
Accuracy Check
Standard Additions Method
This accuracy check should be performed when interferences are suspected
or to verify analytical technique.
1. Snap the neck off a Chloride Voluette Ampule Standard, 12,500 mg/L Cl-.
2. Use a TenSette Pipet to add 0.1 mL of standard to the sample after titration
in Step 6. Resume titration back to the same end point. Record the number
of digits required.
3. Repeat, using additions of 0.2 and 0.3 mL. Titrate to the end point after
each addition.
4. Each 0.1 mL addition of standard should require 12.5 additional digits
of 2.256 N titrant, 25 digits of 1.128 N titrant and 125 digits of 0.2256 N
titrant. If these uniform increases do not occur, refer to Appendix A,
Accuracy Check and Standard Additions in the Digital Titrator Manual to
determine the cause.
Interferences
• Iron in excess of 10 mg/L masks the end point.
• Orthophosphate in excess of 25 mg/L will precipitate the silver.
152
CHLORIDE, continued
• Sulfite in excess of 10 mg/L interferes. Eliminate sulfite interference
by adding three drops of 30% hydrogen peroxide in Step 4.
• Remove sulfide interference by adding the contents of one Sulfide
Inhibitor Reagent Powder Pillow to about 125 mL of sample, mixing
for one minute, and filtering through a folded filter paper.
• Cyanide, iodide and bromide interfere directly and titrate as chloride.
• Neutralize strongly alkaline or acid samples to a pH of 2 to 7 with 5.25 N
Sulfuric Acid Standard Solution or 5.0 N Sodium Hydroxide Standard
Solution. Determine the amount of acid or base necessary in a separate
sample because pH electrodes will introduce chloride into the sample.
Summary of Method
The sample is titrated with Silver Nitrate Standard Solution in the
presence of potassium chromate (from the Chloride 2 Indicator Powder).
The silver nitrate reacts with the chloride present to produce insoluble
white silver chloride. After all the chloride has been precipitated, the
silver ions react with the excess chromate present to form a red-brown
silver chromate precipitate, marking the end point of the titration.
Request Hach Water Analysis Handbook, Publication 8353, to obtain
additional information on chloride determinations.
REQUIRED REAGENTS
Silver Nitrate Chloride Reagent Set (about 50 tests)
Includes: (2) 1057-66, (1) 14396-01, (1) 14397-01, (about 50 tests)............................22880-00
Description
Unit
Cat. No.
Chloride 2 Indicator Powder Pillows .........................................................50/pkg .........1057-66
Silver Nitrate Titration Cartridge, 0.2256 N ..................................................each .......14396-01
Silver Nitrate Titration Cartridge, 1.128 N ....................................................each .......14397-01
Water, demineralized ........................................................................................4 L ...........272-56
REQUIRED APPARATUS
Clippers, for opening pillows .........................................................................each ...........968-00
Digital Titrator................................................................................................each .......16900-01
Flask, erlenmeyer, 250 mL.............................................................................each ...........505-46
Select one or more based on sample concentration
Cylinder, graduated, 10 mL............................................................................each ...........508-38
Cylinder, graduated, 25 mL............................................................................each ...........508-40
Cylinder, graduated, 50 mL............................................................................each ...........508-41
Cylinder, graduated, 100 mL..........................................................................each ...........508-42
153
CHLORIDE, continued
OPTIONAL REAGENTS
Description
Unit
Cat. No.
Chloride Standard Solution, 1000 mg/L Cl- .............................................500 mL........... 183-49
Chloride Standard Solution,
Voluette Ampule, 12,500 mg/L Cl-, 10 mL ............................................ 16/pkg....... 14250-10
Hydrogen Peroxide, 30%, ACS ................................................................200 mL........... 144-45
Sodium Hydroxide Standard Solution, 5.0 N .................................100 mL MDB......... 2450-32
Sulfide Inhibitor Powder Pillows ............................................................. 100/pkg......... 2418-99
Sulfuric Acid Standard Solution, 5.25 N ........................................100 mL MDB......... 2449-32
OPTIONAL APPARATUS
Bottle, wash, poly, 500 mL ............................................................................ each........... 620-11
Clamp, 2-prong extension, 38 mm ................................................................ each....... 21145-00
Clamp Holder................................................................................................. each........... 326-00
Demineralizer Assembly, 473 mL ................................................................. each....... 21846-00
Delivery Tubes, with 180° hook .................................................................. 5/pkg....... 17205-00
Delivery Tubes, 90° with hook for TitraStir ................................................ 5/pkg....... 41578-00
Filter Paper, folded, 12.5 cm.................................................................... 100/pkg......... 1894-57
Funnel, poly, 65 mm ...................................................................................... each......... 1083-67
Hach One Combination pH Electrode with Temp ......................................... each....... 48600-22
pH Meter, EC10, portable .............................................................................. each....... 50050-60
Pipet, TenSette, 0.1 to 1.0 mL........................................................................ each....... 19700-01
Pipet tips for 19700-01 TenSette pipet ...................................................... 50/pkg....... 21856-96
Pipet, volumetric, Class A, 2 mL................................................................... each....... 14515-36
Pipet, volumetric, Class A, 5 mL................................................................... each....... 14515-37
Pipet, volumetric, Class A, 10 mL................................................................. each....... 14515-38
Pipet, volumetric, Class A, 20 mL................................................................. each....... 14515-20
Pipet, volumetric, Class A, 25 mL................................................................. each....... 14515-40
Pipet, volumetric, Class A, 50 mL................................................................. each....... 14515-41
Pipet, volumetric, Class A, 100 mL............................................................... each....... 14515-42
Pipet Filler, safety bulb .................................................................................. each....... 14651-00
Stand, Stirrer/Electrode holder, 115 Vac........................................................ each....... 45300-01
Stand, Stirrer/Electrode holder, 230Vac......................................................... each....... 45300-02
Support ring stand.......................................................................................... each........... 563-00
TitraStir® Mixer/Stand Assembly, 115 Vac.................................................... each....... 19400-00
TitraStir Mixer/Stand Assembly, 230 Vac ..................................................... each....... 19400-10
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
154
Method 8160
For water
CONDUCTIVITY (0 to 19,900 mS)
Using Pocket Pal™ Conductivity Tester
1. Add approximately 2. Immerse the tip of the
30 mL of the sample to a calibrated Pocket Pal
50-mL plastic beaker.
Conductivity Tester one
inch (2.5 cm) below the
Note: Calibration is
necessary; see Calibration surface of the sample
of Pocket Pal Conductivity and stir gently.
Tester following these
steps.
3. When the digital display 4. Rinse the electrode
stabilizes, read and record
the display.
with demineralized water,
and remove the excess by
wiping the tip with a tissue
Note: Readings may not
stabilize for up to 2 minutes. before continuing to the
next sample.
Note: The range of the
Pocket Pal Conductivity
Tester is 100-19,900 mS. To
obtain the proper value in
µS/cm, multiply the large
reading on the Pocket Pal by
the small number (100) in
the upper left hand corner of
the display.
5. When testing is
complete, rinse the
electrode with
demineralized water.
Slide the on/off switch to
off. Cover the electrode
with the protective cap
before storing.
155
Note: To maintain or
improve performance,
periodically clean the
stainless steel electrode by
rinsing it in alcohol.
CONDUCTIVITY, continued
Calibration of Pocket Pal Conductivity Tester
a) Choose a Sodium Chloride Standard Solution that is about the
same Total Dissolved Solids (TDS) value as the sample(s).
See OPTIONAL REAGENTS AND APPARATUS list at the end
of this procedure.
b) Pour about 30 mL of the appropriate standard into a 50-mL beaker.
c) Slide the on/off switch on top of the Pocket Pal Conductivity
Tester to on. See Figure 1.
Figure 1
Pocket Pal Components
d) Remove the protective cap from the bottom of the instrument.
Immerse the electrode tip one inch (2.5 cm) below the surface of
the standard solution. If necessary, calibrate the instrument by
adjusting the calibration trimmer near the pocket clip on the back
of the instrument. See Figure 2. Use the trim tool (screwdriver)
provided to turn the screw. Adjust the value listed for the TDS on
the standard label. Be sure to multiply the large displayed number
by the smaller number in the upper left corner of the display to
obtain the correct TDS in mg/L.
Sampling and Storage
Collect samples in clean plastic or glass bottles. Analyze samples as soon as
possible after collection. However, samples may be stored at least 24 hours by
cooling to 4 °C (39 °F) or below. The conductivity tester will compensate for
any variation of temperature from 25 °C.
Water sample containing oils, grease, or fats will coat the electrode and affect
the accuracy of the readings. If this occurs, clean the probe with a strong
detergent solution, then thoroughly rinse with demineralized water. Mineral
buildup on the probe can be removed with 1:1 Hydrochloric Acid Solution.
156
CONDUCTIVITY, continued
Figure 2
Calibration Trimmer
Conversions
The following table provides equations for converting the conductivity
readings to other units of measure.
From
To
Use this Equation
mS/cm
µS/cm
mS/cm x 1000
µS/cm
mS/cm
µS/cm x 0.001
µS/cm
µmhos/cm
µS/cm x 1
mS/cm
mmhos/cm
mS/cm x 1
µS/cm
mg/L TDS
µS/cm x 0.5
g/L TDS
mg/L TDS
g/L TDS x 1000
mS/cm
g/L TDS
mS/cm x 0.5
mg/L TDS
g/L TDS
mg/L TDS x 0.001
mg/L TDS
gpg TDS
mg/L TDS x 0.05842
g/L TDS
gpg TDS
g/L TDS x 58.42
µS/cm
ohms cm
1,000,000 ÷ µS/cm
mS/cm
ohms cm
1,000 ÷ mS/cm
mS/cm
dS/m
mS/cm x 1.0
Accuracy Check
Pour a Sodium Chloride Standard Solution with a conductivity value in
the same range as the sample into a beaker. Perform the conductivity
measurements as described in the procedure. The conductivity reading
should be the same as listed on the Standard Solution label if the meter
is calibrated correctly.
157
CONDUCTIVITY, continued
Summary of Method
Electrolytic conductivity is the capacity of ions in a solution to carry
electrical current and is the reciprocal of the solution resistivity. Current is
carried by inorganic dissolved solids (e.g. chloride, nitrate, sulfate, and
phosphate anions) and cations (e.g. sodium, calcium, magnesium, iron
and aluminum). Organic material like oils, phenols, alcohols and sugars
do not carry electrical current well and thus do not have enough
conductivity for a useful estimate of concentration.
Measuring conductivity is done by measuring the resistance occurring in an
area of the test solution defined by the probe’s physical design. Voltage is
applied between the two electrodes immersed in the solution, and the
voltage drop caused by the resistance of the solution is used to calculate
conductivity per centimeter. The basic unit of measure for conductivity is
the Siemen (or mho), the reciprocal of the ohm in the resistance
measurement. Because ranges normally found in aqueous solutions are
small, milliSiemens/cm (10-3 S or mS/cm) and microSiemens/cm (10-6 S or
µS/cm) are used most commonly.
REQUIRED REAGENTS AND APPARATUS
Description
Cat. No.
Pocket Pal Conductivity Tester ..................................................................................... 44375-00
Beaker, poly, 50 mL....................................................................................... each......... 1080-41
OPTIONAL REAGENTS AND APPARATUS
Battery, optional, 1.4V Zinc-Air .................................................................. 4/pkg....... 23678-00
Gallic Acid Solution ....................................................................... 50 mL SCDB....... 14423-26
Hydrochloric Acid Solution, 1:1...............................................................500 mL........... 884-49
Sodium Chloride Standard Solution,
1000 ±10 µS/cm, 500 ±5 mg/L TDS .....................................................100 mL....... 14400-42
Sodium Chloride Standard Solution,
1990 ±20 µS/cm, 995 ±10 mg/L TDS ...................................................100 mL......... 2105-42
Sodium Chloride Standard Solution,
18000 ± 50µS/cm, 9000 ±25 mg/L TDS ...............................................100 mL....... 23074-42
Wash Bottle, 125-mL ..................................................................................... each........... 620-14
Water, demineralized ........................................................................................ 4L........... 272-56
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
158
HARDNESS, TOTAL (10 - 4000 mg/L as CaCO3)
Method 8213
For water, wastewater and seawater
Using EDTA with a Digital Titrator
1. Select a sample size 2. Insert a clean
and an EDTA Titration
Cartridge corresponding
to the expected total
hardness as calcium
carbonate (CaCO3)
concentration. Use Table
1 for concentrations in
mg/L or Table 2 for
concentrations in
German degrees of
hardness (G.d.h.).
delivery tube into the
titration cartridge.
Attach the cartridge
to the titrator body.
See General
Description, Step-byStep, of the Digital
Titrator Manual for
assembly instructions,
if necessary.
3. Turn the delivery
knob to eject a few drops
of titrant. Reset the
counter to zero and wipe
the tip.
4. Use a graduated
cylinder or pipet to
measure the sample
volume from Table 1 or
Table 2. Transfer the
sample into a clean
Note: For added
250-mL erlenmeyer
convenience use the
flask. Dilute to about the
®
TitraStir Stirring
100-mL mark with
Apparatus, see General
Description, Step 3 in Step- demineralized water,
if necessary.
by-Step, of the Digital
Titrator Manual.
Note: One German degree
hardness equals 17.9 mg/L
hardness as CaCO3.
Note: Collect at least
100 mL of sample in a glass
or polyethylene container.
Samples may be held up to
seven days before analysis if
stored at 4 oC and acidified
to pH 2 with concentrated
nitric acid. Neutralize
acidified sample to pH 7 with
ammonium hydroxide before
testing.
159
HARDNESS, TOTAL, continued
5. Add 2 mL of Buffer 6. Add the contents of
Solution, Hardness, 1,
and swirl to mix.
7. Place the delivery
8. Use one of the
tube tip into the solution following formulas
and swirl the flask while to calculate the final
titrating with EDTA
concentration:
from red to pure blue.
Digits Required x Digit Multiplier
(Table 1) = mg/L Total Hardness
Record the number of
Note: Four drops of ManVer
as CaCO3
digits
required.
Hardness Indicator Solution
one ManVer® 2
Hardness Indicator
Powder Pillow and swirl
to mix.
or a 0.1 g scoop of ManVer 2
Hardness Indicator Powder
may be substituted for the
powder pillow.
Note: Titrate slowly near
the end point because the
reaction is slow, especially
in cold samples.
Digits Required x Digit Multiplier
(Table 2) = G.d.h.
Note:
mg/L Total Hardness ÷ 50 =
meq/L Total Hardness =
meq/L Ca + meq/L Mg
Note: The magnesium
concentration may be
determined by subtracting the
results of the calcium
determination from the above
total hardness determination.
Table 1
Range
(mg/L as CaCO3)
Sample
Volume
(mL)
Titration
Cartridge
(M EDTA)
Catalog
Number
Digit
Multiplier
10-40
40-160
100-400
200-800
500-2000
1000-4000
100
25
100
50
20
10
0.0800
0.0800
0.800
0.800
0.800
0.800
14364-01
14364-01
14399-01
14399-01
14399-01
14399-01
0.1
0.4
1.0
2.0
5.0
10.0
Table 2
Range (G.d.h.)
Sample
Volume
(mL)
Titration
Cartridge
(M EDTA)
Catalog
Number
Digit
Multiplier
1-4
4-16
10-40
25-100
>100
100
25
50
20
10
0.1428
0.1428
0.714
0.714
0.714
14960-01
14960-01
14959-01
14959-01
14959-01
0.01
0.04
0.1
0.25
0.5
160
HARDNESS, TOTAL, continued
Hardness Relationships
mg/L Total Hardness as Ca = mg/L Total Hardness as (CaCO 3 ) × 0.400
mg/L Total Hardness (as CaCO 3 ) =
mg/L Ca (as CaCO 3 ) + mg/L Mg (as CaCO 3 )
mg/L Total Hardness (as CaCO3) ÷ 50 = meq/L Total Hardness
or meq/L Ca + meq/L Mg
Accuracy Check
Standard Additions Method
To verify analytical technique use 20 mL of the Calcium Standard Solution,
1000 mg/L as CaCO3. Perform the procedure as described above. This
solution will read 1000 mg/L or 55.9 G.d.h.
Perform this accuracy check when interferences are suspected.
1. Snap the neck off a Hardness Voluette Ampule Standard, 10,000 mg/L
as CaCO3.
2. Use a TenSette Pipet to add 0.1 mL of standard to the sample titrated
in Step 7. Resume titration back to the same end point. Record the
number of digits required.
3. Repeat, using two more additions of 0.1 mL. Titrate to the end point
after each addition.
4. Each 0.1 mL addition of standard should require 10 additional digits of
0.800 M titrant, 100 digits of 0.0800 M titrant, 11 digits of 0.714 M, or
56 digits of 0.1428 M titrant. If these uniform increases do not occur,
refer to Appendix A, Accuracy Check and Standard Additions in the
Digital Titrator Manual to determine the cause.
Interferences
• Although less common than calcium and magnesium, other
polyvalent metal ions cause the same hardness effects and will be
included in the results.
• Some transition and heavy metals complex the indicator and prevent the
color change at the end point.
• Iron does not interfere up to 15 mg/L. Above this level it causes a redorange to green end point which is sharp and usable up to 30 mg/L
iron. Substitute a 0.0800 M CDTA or 0.800 M CDTA titration
cartridge for the 0.0800 M EDTA or 0.800 M EDTA titration
cartridges, respectively, if iron interference is probable.
161
HARDNESS, TOTAL, continued
• Manganese titrates directly up to 20 mg/L but masks the end point
above this level. Adding a 0.1-gram scoop of hydroxylamine
hydrochloride monohydrate raises this level to 200 mg/L manganese.
DANGER
Potassium cyanide is toxic.
Always add it after
the potassium
hydroxide. Excess
potassium cyanide does not
affect results. All
cyanide wastes
should be disposed
of by adding an
excess of strongly
alkaline sodium
hypochlorite
solution (bleach)
with stirring. Use
good ventilation.
Allow to stand
for 24 hours
before disposal.
• Copper interferes at levels of 0.10 and 0.20 mg/L. Cobalt and nickel interfere
at all levels and must be absent or masked. A 0.5-gram scoop of potassium
cyanide removes interference from up to 100 mg/L copper, 100 mg/L zinc,
100 mg/L cobalt and 100 mg/L nickel. It raises the permissible aluminum
level to 1 mg/L. Metals masked with cyanide will not be included in the
hardness result.
• Orthophosphate causes a slow end point and polyphosphate must be
absent for accurate results.
• Acidity and alkalinity at 10,000 mg/L (as CaCO3) do not interfere.
• Saturated sodium chloride solutions do not give a distinct end point,
but the titration can be run directly on sea water.
• Adding the contents of one CDTA Magnesium Salt Powder Pillow
removes metal interferences at or below the levels shown in Table 3.
Table 3
Metal
CDTA Removes Interference Below This Level
Aluminum
50 mg/L
Cobalt
200 mg/L
Copper
100 mg/L
Iron
100 mg/L
Manganese
200 mg/L
Nickel
400 mg/L
Zinc
300 mg/L
• If more than one metal is present at or above the concentrations
shown above, an additional CDTA Magnesium Salt Powder Pillow
may be required.
• Results obtained by this procedure include the hardness contributed by the
metals. If the concentration of each metal is known, a correction can be
applied to obtain the calcium and magnesium hardness concentration. The
hardness (in mg/L as CaCO3) contributed by each mg/L of metal is listed
below, and can be subtracted from the total hardness value obtained above
to determine the calcium and magnesium hardness. See Table 4.
162
HARDNESS, TOTAL, continued
.
Table 4
Metal
Hardness Contributed by Each mg/L of Metal
Aluminum
3.710
Barium
0.729
Cobalt
1.698
Copper
1.575
Iron
1.792
Manganese
1.822
Nickel
1.705
Strontium
1.142
Zinc
1.531
• Barium, strontium and zinc titrate directly.
• Highly buffered samples or extreme sample pH may exceed the
buffering capacity of the reagents and require sample pretreatment; see
Interferences, pH, Section I of the DR/2010 Spectrophotometer
Procedures Manual.
Summary of Method
After the sample is buffered to pH 10.1, ManVer 2 Hardness Indicator is
added, and forms a red complex with a portion of the calcium and
magnesium in the sample. EDTA titrant reacts first with the free calcium
and magnesium ions, then with those bound to the indicator, causing it to
change to a blue color at the end point.
163
HARDNESS, TOTAL, continued
REQUIRED REAGENTS
Total Hardness Reagent Set (about 100 tests)
Includes: (1) 424-32, (1) 851-49, (1) 14364-01, (1) 14399-01 ................................. 22720-00
Description
Unit
Cat. No.
Buffer Solution, Hardness 1............................................................100 mL MDB........... 424-32
ManVer 2 Hardness Indicator Powder Pillow.......................................... 100/pkg........... 851-99
Water, demineralized ....................................................................................... 4 L........... 272-56
Select one or more based on sample concentration
EDTA Titration Cartridge, 0.0800 M............................................................. each....... 14364-01
EDTA Titration Cartridge, 0.1428 M............................................................. each....... 14960-01
EDTA Titration Cartridge, 0.714 M............................................................... each....... 14959-01
EDTA Titration Cartridge, 0.800 M............................................................... each....... 14399-01
REQUIRED APPARATUS
Clippers, for opening pillows......................................................................... each........... 968-00
Digital Titrator ............................................................................................... each....... 16900-01
Flask, erlenmeyer, 250 mL ............................................................................ each........... 505-46
Select one or more based on sample concentration
Cylinder, graduated, 10 mL ........................................................................... each........... 508-38
Cylinder, graduated, 25 mL ........................................................................... each........... 508-40
Cylinder, graduated, 50 mL ........................................................................... each........... 508-41
Cylinder, graduated, 100 mL ......................................................................... each........... 508-42
OPTIONAL REAGENTS
Ammonium Hydroxide, 10%........................................................100 mL MDB*....... 14736-32
Calcium Chloride Standard Solution, 1000 mg/L as CaCO3 ..................1000 mL........... 121-53
CDTA Magnesium Salt Powder Pillows.................................................. 100/pkg....... 14080-99
CDTA Titration Cartridge, 0.0800 M ............................................................ each....... 14402-01
CDTA Titration Cartridge, 0.800 M .............................................................. each....... 14403-01
Calcium Standard Solution, Voluette Ampule,
10,000 mg/L as CaCO3, 10 mL .............................................................. 16/pkg......... 2187-10
Hydroxylamine Hydrochloride, Monohydrate, ACS................................... 113 g........... 246-14
ManVer 2 Hardness Indicator Powder ......................................................... 113 g........... 280-14
ManVer Hardness Indicator Solution............................................100 mL MDB*........... 425-32
Nitric Acid Solution, 1:1...........................................................................500 mL......... 2540-49
Nitric Acid, ACS.......................................................................................500 mL........... 152-49
Potassium Cyanide, ACS ............................................................................. 125 g........... 767-14
* Contact Hach for larger sizes.
164
HARDNESS, TOTAL, continued
OPTIONAL APPARATUS
Description
Unit
Cat. No.
Bottle, wash, poly, 500 mL ............................................................................each ...........620-11
Clamp 2-prong, extension, 38 mm .................................................................each .......21145-00
Clamp Holder .................................................................................................each ...........326-00
Demineralizer Assembly, 473 mL..................................................................each .......21846-00
Delivery Tubes, with 180° hook...................................................................5/pkg .......17205-00
Delivery Tubes, 90° with hook .....................................................................5/pkg .......41578-00
pH meter, EC10, portable...............................................................................each .......50050-60
Hach One Combination pH Electrode with Temp .........................................each .......48600-22
pH Indicator Paper, 1.0 to 11 pH..........................................................5 rolls/pkg ...........391-33
Pipet, TenSette, 0.1 to 1.0 mL ........................................................................each .......19700-01
Pipet Tips, for 19700-01 TenSette Pipet ....................................................50/pkg .......21856-96
Pipet, volumetric, Class A, 10 mL .................................................................each .......14515-38
Pipet, volumetric, Class A, 20 mL .................................................................each .......14515-20
Pipet, volumetric, Class A, 25 mL .................................................................each .......14515-40
Pipet, volumetric, Class A, 50 mL .................................................................each .......14515-41
Pipet, volumetric, Class A, 100 mL ...............................................................each .......14515-42
Pipet Filler safety bulb ...................................................................................each .......14651-00
Spoon, measuring, 1.0 gram...........................................................................each ...........510-00
Spoon, measuring, 0.5 gram...........................................................................each ...........907-00
Support ring stand ..........................................................................................each ...........563-00
TitraStir Mixer/Stand Assembly, 115 Vac......................................................each .......19400-00
TitraStir Mixer/Stand Assembly, 230 Vac......................................................each ...... 19400-10
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
165
166
Method 8039
For water, wastewater, and seawater*
NITRATE, HR (0 to 30.0 mg/L NO3--N)
Cadmium Reduction Method (Powder Pillows or AccuVac Ampuls)
Using Powder Pillows
500 nm
1. Enter the stored
program number for
high range nitrate
nitrogen (NO3--N).
Press: 3 5 5 ENTER
The display will show:
Dial nm to 500
2. Rotate the
3. Fill a sample cell
wavelength dial until the with 25 mL of sample.
small display shows:
500 nm
When the correct
wavelength is dialed in,
the display will quickly
show:
Zeroing. . .
Note: The Pour-Thru Cell
can be used if rinsed well
then:
with demineralized water
mg/L NO3--N HR
after use. Avoid pouring
any cadmium particles into
the cell.
4. Add the contents of
one NitraVer 5 Nitrate
Reagent Powder Pillow
Note: A reagent blank must
be determined on each new to the cell (the prepared
sample). Stopper.
lot of NitraVer® 5 Nitrate
Reagent. Perform Steps 3 to
12 using demineralized
water as the sample.
Subtract this value from
each result obtained with
this lot of reagent.
* For seawater, a manual calibration is required; see Interferences following the procedure.
167
NITRATE, HR, continued
5. Press:SHIFT TIMER 6. When the timer
beeps, press:
Shake the cell vigorously
SHIFT TIMER
until the timer beeps in
one minute.
A five-minute reaction
period will begin.
Note: Shaking time and
technique influence color
development. For most
accurate results, make
successive tests on a
standard solution. Adjust
the shaking time to obtain
the correct result.
9. Press: ZERO
The display will show:
Zeroing. . .
then:
0.0 mg/L NO3--N HR
7. Fill another sample
8. When the
cell with 25 mL of
sample (the blank).
timer beeps, the display
will show:
mg/L NO3--N HR
Place the blank into the
cell holder. Close the
light shield.
Note: An amber color will
develop if nitrate nitrogen
is present.
10. Remove the stopper.
11. Press: READ
Place the prepared sample
The display will show:
into the cell holder. Close
the light shield.
Reading. . .
Note: A cadmium deposit
will remain after the
NitraVer 5 Nitrate Reagent
Powder dissolves and will
not affect results.
then the result in mg/L
nitrate nitrogen (NO3--N)
will be displayed
Note: Rinse the
sample cell immediately
after use to remove all
cadmium particles.
168
NITRATE, HR, continued
Using AccuVac Ampuls
500 nm
1. Enter the stored
program number for
high range nitrate
nitrogen (NO3--N)AccuVac Ampuls.
Press: 3 6 1 ENTER
The display will show:
Dial nm to 500
2. Rotate the
3. Collect at least 40 mL
wavelength dial until the of sample in a 50-mL
small display shows:
beaker. Fill a NitraVer 5
Nitrate Reagent AccuVac
500 nm
Ampul with sample.
When the correct
Note: Keep the tip
wavelength is dialed in, immersed while the ampul
the display will quickly fills completely.
show: Zero Sample
then:
mg/L NO3--N HR AV
Note: A reagent blank must be
determined on each new lot of
NitraVer 5 Reagent. Repeat
Steps 3 to 11 using
demineralized water as the
sample. Subtract this value
from each result obtained with
this lot of reagent.
169
4. Press: SHIFT TIMER
A one-minute mixing
period will begin.
Invert the ampul
repeatedly until the timer
beeps. Wipe off any
liquid or fingerprints.
Note: Shaking time and
technique influence color
development. For most
accurate results, make
successive tests on a
10 mg/L Nitrate Nitrogen
Standard Solution. Adjust
the shaking time to obtain
the correct result.
NITRATE, HR, continued
5. When the timer
6. Fill a zeroing vial
7. Place the AccuVac
8. When the
beeps, press:
with at least 10 mL of
sample (the blank).
Vial Adapter into the
cell holder.
timer beeps, the
display will show:
SHIFT TIMER
Note: Place the grip tab at
the rear of the cell holder.
A five-minute reaction
period will begin.
Note: A cadmium deposit
will remain after the
NitraVer 5 Nitrate Reagent
Powder dissolves and will
not affect results.
Note: An amber color will
develop if nitrate nitrogen
is present.
9. Press: ZERO
The display will show:
Zeroing. . .
then:
--N HR
0.0 mg/L NO3
AV
10. Place the AccuVac
11. Press: READ
ampul into the cell holder.
The display will show:
Close the light shield.
Reading. . .
then the nitrate result in
mg/L nitrogen (NO3--N)
will be displayed.
170
mg/L NO3--N HR AV
Place the blank into the
cell holder. Close the
light shield.
NITRATE, HR, continued
Sampling and Storage
Collect samples in clean plastic or glass bottles. Store at 4 °C (39 °F) or lower
if the sample is to be analyzed within 24 to 48 hours. Warm to room
temperature before running the test. For storage periods up to 14 days, adjust
sample pH to 2 or less with sulfuric acid, ACS, (about 2 mL per liter).
Sample refrigeration is still required.
Before testing the stored sample, warm to room temperature. Neutralize
the sample with 5.0 N Sodium Hydroxide Standard Solution.
Do not use mercury compounds as preservatives.
Correct test results for volume additions; see Correction for Volume
Additions in Section I of the DR/2010 Spectrophotometer Procedures
Manual for more information.
Accuracy Check
Standard Additions Method
a) Snap the neck off a fresh High Range Nitrate Nitrogen Voluette
Ampule Standard, 500 mg/L NO3--N.
b) Use the TenSette Pipet to add 0.1, 0.2, and 0.3 mL of standard to
three 25-mL samples. Mix each thoroughly. (For AccuVac
Ampuls, use 50-mL beakers.)
c) Analyze each sample as described above. The nitrogen
concentration should increase 2.0 mg/L for each 0.1 mL of
standard added.
d) If these increases do not occur, see Standard Additions in Section I
of the DR/2010 Spectrophotometer Procedures Manual for
more information.
Standard Solution Method
Use a 10.0 mg/L Nitrate Nitrogen Standard Solution listed under Optional
Reagents to check test accuracy. Or, this can be prepared by diluting 1.00 mL of
solution from a High Range Nitrate Nitrogen Voluette Ampule Standard
Solution, 500 mg/L NO3--N, to 50.0 mL with demineralized water. Use this
standard in place of sample in Step 3 of the procedures.
Precision
In a single laboratory using standard solutions of 20.0 mg/L nitrate
nitrogen (NO3--N) and two representative lots of reagent with the
DR/2010 Spectrophotometer, a single operator obtained a standard
deviation of +0.8 mg/L nitrate nitrogen.
171
NITRATE, HR, continued
Using standard solutions of 30.0 mg/L (NO3--N) and one representative
lot of AccuVac Ampuls with the DR/2010 Spectrophotometer, a single
operator obtained a standard deviation of +2.3 mg/L nitrate nitrogen.
Interferences
• Strong oxidizing and reducing substances will interfere.
• Ferric iron causes high results and must be absent.
• Chloride concentrations above 100 mg/L will cause low results. The
test may be used at high chloride levels (i.e., seawater), but a
calibration must be performed using standards spiked to the same
chloride concentration. See User Stored Programs in the DR/2010
Sprectrophotometer Instrument Manual for more information.
• Highly buffered samples or extreme sample pH may exceed the
buffering capacity of the reagents and require sample pretreatment; see
pH Interferences, Section I of the DR/2010 Spectrophotometer
Procedures Manual.
Summary of Method
Cadmium metal reduces nitrates present in the sample to nitrite. The
nitrite ion reacts in an acidic medium with sulfanilic acid to form an
intermediate diazonium salt. This salt couples to gentisic acid to form an
amber-colored product.
REQUIRED REAGENTS (Using Powder Pillows)
Quantity Required
Per Test
Description
Unit
Cat. No.
NitraVer 5 Nitrate Reagent Powder Pillows, 25 mL...... 1 pillow............ 100/pkg....... 14034-99
REQUIRED APPARATUS (Using Powder Pillows)
Stopper, rubber, size 2..........................................................1 ................... 12/pkg......... 2118-02
Sample Cell, 25 mL, matched pair ................................................................. pair....... 20950-00
REQUIRED REAGENTS (Using AccuVac Ampuls)
Quantity Required
Per Test
Description
Unit
Cat. No.
NitraVer 5 Nitrate Reagent AccuVac Ampul................. 1 ampul.............. 25/pkg....... 25110-25
172
NITRATE, HR, continued
REQUIRED APPARATUS (Using AccuVac Ampuls)
Adapter, AccuVac Vial ........................................................ 1........................each .......43784-00
Beaker, 50 mL ..................................................................... 1........................each ...........500-41
Zeroing Vial......................................................................... 1........................each .......21228-00
OPTIONAL REAGENTS
Description
Unit
Cat. No.
-
Nitrate Nitrogen standard Solution, 10 mg/L NO3 -N.............................. 500 mL ...........307-49
Nitrate Nitrogen Standard Solution, Voluette Ampule, 500 mg/L
(NO3--N), 10 mL ....................................................................................16/pkg .......14260-10
Sodium Hydroxide Standard Solution, 5.0 N........................................... 59 mL* .........2450-26
Sulfuric Acid, ACS................................................................................. 500 mL* ...........979-49
Water, demineralized ........................................................................................4 L ...........272-56
OPTIONAL APPARATUS
AccuVac Ampul Snapper Kit .........................................................................each .......24052-00
Ampule Breaker Kit .......................................................................................each .......21968-00
Cylinder, graduated, 25 mL............................................................................each .........1081-40
Dropper, for 1-oz bottle..................................................................................each .........2258-00
pH Indicator Paper, 1 to 11 pH.............................................................5 rolls/pkg ...........391-33
pH Meter, EC10, portable ..............................................................................each .......50050-00
Pipet, serological, 2 mL..................................................................................each ...........532-36
Pipet, TenSette, 0.1 to 1.0 mL ........................................................................each .......19700-01
Pipet Tips, for 19700-01 TenSette Pipet ....................................................50/pkg .......21856-96
Pipet, volumetric, Class A, 1.00 mL ..............................................................each .......14515-35
Pipet Filler, safety bulb...................................................................................each .......14651-00
Pour-Thru Cell Assembly Kit ........................................................................each .......45215-00
Sample Cells, 1-inch, polystyrene, disposable...........................................12/pkg .......24102-12
Thermometer, -10 to 110 °C...........................................................................each .........1877-01
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
173
174
Method 8156
For water and wastewater
pH
Hach One® Combination pH Electode Method with the EC10 Portable Meter
USEPA approved for reporting*
Sample pH Measurement (Calibration is required)
FIL
L
1. Press the Dispenser
2. Swirl the sample
Button once (it will click). and place the electrode
Rinse and blot dry.
in the container. Be
sure the entire sensing
end is submerged.
LIN
E
3. Record the pH value
4. Rinse the electrode
when the display is stable. thoroughly with
demineralized water and
blot dry.
Two-Standard Calibration in Automatic Mode with Temperature Probe
1. Press the POWER key. 2. Ensure the meter is in
The display will light.
pH mode.
Note: Be sure no air
bubbles are trapped inside
the tip of the electrode or
dispenser tubing.
3. Press the CAL key. The 4. Place the electrode
slope data of the previous
calibration or a default
slope will appear. Then the
meter will go into measure
mode with a “P1” (Point 1)
in the display.
into a pH 4 buffer
solution and press the
dispenser button. The
temperature will show
the actual solution
temperature and
“ATC” (Automatic
Note: Hach buffers are
Temperature
available as powders or
Compensation) will
solutions. They are colorcoded for added convenience. appear in the display if
the temperature probe
is connected.
Note: Buffer solutions
(pH 4, 7 and 10) may be
used in any order.
* Procedure is equivalent to USEPA method 150.1 and Standard Methods Part 4500-H+ for water and wastewater.
175
pH, continued
FIL
L
5. When the display
stabilizes, the meter will
beep and show the
temperature corrected
value for the pH 4 buffer
and a ready indicator.
Press YES to accept this
value for the first buffer.
LIN
E
6. Rinse the electrode
7. Place the electrode in
with demineralized
the pH 7 buffer and press
water and blot dry with a the dispenser button.
paper towel.
8. When the display
stabilizes it will beep and
show the temperature
corrected value for the
pH 7 buffer and “ready”.
Press the YES key to
accept this value for the
second buffer.
Note: Pressing any key
other than the YES key at
this point will cancel the
calibration values entered
and the meter will default to
the previous slope and adjust
the offset only.
9. The slope will appear
in the display. It should be
59.0 ±3 (mV/decade).
Press the YES key to
accept this slope. Rinse
the electrode with
demineralized water or a
portion of the sample to
be measured. Blot dry
with a paper towel.
10. Place the electrode
11. To review, press the
into the sample. Press the
Dispenser Button. The
meter will measure the
sample pH.
CAL key to show the
A value outside the range of
6.95-7.05 indicates the
analyst should recalibrate.
Note: For other calibrations
or more complete operation
instructions, refer to the
instrument manual.
electrode slope in the
display. The slope should
be 59.0 ± 3 mV/decade.
The meter will then attempt
Note: Repeat step 10 for
to re-calibrate. Press
each sample. Check the
MODE
again to return to
calibration against 7.0 pH
Buffer after every 10 samples. measurement mode.
176
pH, continued
Sampling and Storage
Collect samples in clean plastic or glass bottles. Fill completely and cap tightly.
Cool to 4 °C (39 °F) and determine pH within six hours. If samples cannot be
analyzed within six hours, report the actual holding time with the results.
Interferences
• Acid error is negligible.
• Sodium error, usually present in alkaline solutions, is low, but
increases at pH values higher than pH 11.
Hach One pH Electode
Short-term Storage
Between measurements, store the electrode in a pH Electrode Storage
Solution. If electrode storage solution is not available, use one of the
following solutions:
1. 200 mL of pH 7 buffer with one gram of potassium chloride added
(this is the preferred solution).
2. pH 7 buffer solution.
For measurements of low-ionic strength sample, condition the electrode
by soaking in demineralized water for 1 to 2 hours.
Long-term Laboratory Storage
For storage more than 2 weeks, continue to store the electrode in pH
Electrode Storage Solution. Maintain the AgCl concentration around the
wire by periodically (every few days) pumping electrolyte through the
electrode. Add demineralized water as needed to maintain the liquid level
around the electrode.
Long-term Field or Shelf Storage
Replace the black cap (Cat. No. 42389-00) that was on the electrode
when it was shipped. Periodically check the cotton ball in the tip of the
cap for moisture, adding a few drops of the pH electrode storage
solution when necessary.
If it becomes necessary to replace the cotton ball, add a few drops of pH
Electrode Storage Solution or pH 7 buffer to the replacement cotton and
place it into the end of the cap. Maintain the moisture as above. Salt
crystals may grow on the electrode tip. These are not harmful and may be
removed by rinsing the tip with demineralized water.
177
pH, continued
Normal Cleaning
If the electrode response time slows, the cause may be a fouled reference
element or a contaminated glass bulb. Normal cleaning or reconditioning
of the electrode can be performed in the following manner:
Immerse the electrode tip in 0.1N Hydrochloric Acid followed by
immersion in 0.1N Sodium Hydroxide and again in 0.1N Hydrochloric
Acid, each for a 2-minute period. Rinse with demineralized water and
soak in demineralized water for at least 15 minutes.
Remove oils and fats by immersing the electrode tip in a detergent
solution such as Alconox™. Use a brush or ultrasonic bath if necessary.
Avoid scratching the glass bulb.
Remove organic films from the glass bulb by using an appropriate
solvent, such as methanol or acetone.
If these steps fail to improve electrode response, replace the electrode.
EC10 Portable pH Meter Battery Replacement
Replace the 9V alkaline battery in the EC10 pH Meter with a battery of
similar specifications (Hach Cat. No. 50110-00) when the display dims.
Refer to the meter manual for installation. Estimated battery life is
approximately 40 hours of use. An optional eliminator is also available.
Summary of Method
The Hach One Combination pH Electrode responds to the hydrogen ion
concentration (activity) by developing an electrical potential at the glass/
liquid interface. At a constant temperature, this potential varies linearly
with the pH of the solution being measured. The electrode has a freediffusion junction which eliminates clogging problems.
REQUIRED REAGENTS AND APPARATUS
Description
Unit
Cat. No.
Buffer Powder Pillows, pH 4 and 7 ........................................................... 20/pkg....... 22992-64
KCl Reference Electrode Gel Cartridge ...................................................... 2/pkg....... 25469-02
Beaker, Griffin, 100 mL................................................................................. each....... 22994-42
Clippers, for opening powder pillows............................................................ each........... 968-00
EC10 pH Meter and Hach One pH Electrode, case, accessories................... each....... 50050-10
Hach One Combination pH Electrode w/Temp (replacement) ...................... each....... 48600-22
178
pH, continued
OPTIONAL REAGENTS
Description
Unit
Cat. No.
Acetone, ACS ........................................................................................... 500 mL .......14429-49
Buffer Powder Pillows, pH 4 (red).............................................................50/pkg .......22269-66
Buffer Powder Pillows, pH 7 (yellow) .......................................................50/pkg .......22270-66
Buffer Powder Pillows, pH 9......................................................................50/pkg .......14107-66
Buffer Powder Pillows, pH 10 (blue) .........................................................50/pkg .......22271-95
Buffer Solution, pH 4 (red) ...................................................................... 500 mL .......22834-49
Buffer Solution, pH 7 (yellow)................................................................. 500 mL .......22835-49
Buffer Solution, pH 10 (blue) .................................................................. 500 mL .......22836-49
Detergent Alconox ..................................................................................... 1.8 Kg .......20880-00
Hydrochloric Acid Standard Solution, 0.1 N ...............................................1 liter .......14812-53
pH Electrode Storage Solution................................................................. 500 mL .......50301-49
pH Electrode Storage Solution Powder Pillows...........................................pk/20 .......26573-64
Sodium Hydroxide Standard Solution, 0.100N............................................1 liter ...........191-53
Water, demineralized ........................................................................................4 L ...........272-56
OPTIONAL APPARATUS
Beaker, poly, 50 mL .......................................................................................each .........1080-41
Clippers, for opening powder pillows ............................................................each ...........968-00
Cylinder, mixing, graduated, 50 mL ..............................................................each .........1896-41
Electromagnetic stirrer and electrode holder, (115 V North American) ........each .......45300-01
Electromagnetic stirrer and electrode holder, (230 V) ...................................each .......45300-02
Battery Eliminator, for EC10 pH Meter, 115 V, UL/CSA approved
with North American style plug..................................................................each .......50070-00
Battery Eliminator, for EC10 pH Meter, 230 V, VDE approved
with Continental European style plug.........................................................each .......50070-01
Battery, replacement, 9V ...............................................................................each .......50110-00
EC20 Portable pH/ISE Meter, Case Accessories (no electrode)....................each .......50075-10
EC30 Benchtop pH Meter with Hach One Electrode,
(115 V with North American style plug) ....................................................each .......50100-10
EC30 Benchtop pH Meter with Hach One Electrode,
(230 V with Continental European style plug) ...........................................each .......50100-11
EC40 Benchtop pH/ISE Meter with Hach One Electrode,
(115 V with North American style plug) ....................................................each .......50125-10
EC40 Benchtop pH Meter with Hach One Electrode,
(230 V with Continental European style plug) ...........................................each .......50125-11
CO150 Portable Conductivity Meter, Probe, Case Accessories.....................each .......50150-00
Comb. pH Electrode with Temperature (Gel Filled) ......................................each .......50200-00
Comb. pH Electrode (Refillable)....................................................................each .......50215-00
Temperature Probe .........................................................................................each .......50270-00
Stir Bar, 22.2 x 4.76 mm (7/8 x 3/16”)...........................................................each .......45315-00
Thermometer, armored, -10 to 110 °C ...........................................................each .........1877-01
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
179
180
Method 8048
PHOSPHORUS, REACTIVE (0 to 0.83 mg/L P ; 0 to 2.50 mg/L PO43- )
For water, wastewater, seawater
(Also called Orthophosphate) PhosVer® 3 (Ascorbic Acid) Method*
(Powder Pillows or AccuVac Ampuls) USEPA Accepted for wastewater analysis reporting**
Using Powder Pillows
890 nm
1. Enter the stored
2. Rotate the wavelength 3. Insert a 10-mL
program number for
reactive phosphorus,
ascorbic acid method,
powder pillows.
Press:
dial until the small
display shows:
890 nm
4 9 0 ENTER
The display will show:
Dial nm to 890
Note: The Pour-Thru Cell
can be used with 25-mL
reagents only.
Cell Riser into the
cell compartment.
4. Fill a 10-mL
sample cell with 10 mL
of sample.
When the correct
wavelength is dialed in,
the display will quickly
show:
Zero Sample
then:
mg/L PO43- PV
then:
Use the arrow keys to
select the “P” form of
phosphorus measurement.
* Adapted from Standard Methods for the Examination of Water and Wastewater.
** Procedure is equivalent to USEPA method 365.2 and Standard Methods Part 4500-P-E for wastewater.
181
PHOSPHORUS, REACTIVE, continued
5. Add the contents of
one PhosVer 3
Phosphate Powder
Pillow for 10-mL
sample to the cell (the
prepared sample). Swirl
immediately to mix.
6. Press: SHIFT TIMER
9. Press: ZERO
10. Place the prepared
sample into the cell
holder. Close the
light shield.
A two-minute reaction
period will begin.
7. Fill a second 10-mL
8. When the timer
sample cell with 10 mL of beeps, the display will
sample (this is the blank). show: mg/L P PV
Note: Use a 10 minute
reaction period if
determining total
phosphorus following the
Note: A blue color will form acid-persulfate digestion.
if phosphate is present.
The display will show:
Zeroing. . .
then:
0.00 mg/L P PV
Place the blank into the
cell holder. Close the
light shield.
11. Press: READ
The display will show:
Reading. . .
Note: Run a reagent blank then the results in mg/L P
for this test. Use
will be displayed.
demineralized water in
place of the sample in Steps
4 and 7. Subtract this result
from all test results run
with this lot of PhosVer 3.
182
PHOSPHORUS, REACTIVE, continued
Using AccuVac Ampuls
890 nm
1. Enter the stored
2. Rotate the wavelength 3. Fill a zeroing vial (the 4. Place the AccuVac
program number for
reactive phosphorus,
ascorbic acid method,
AccuVac Ampuls.
dial until the small
display shows:
Press: 4 9 2 ENTER
The display will show:
Dial nm to 890
blank) with at least
10 mL of sample. Collect
at least 40 mL of sample
in a 50-mL beaker.
890 nm
When the correct
wavelength is dialed in,
the display will quickly
show: Zero Sample
then:
mg/L PO43- PV AV
then:
Use the arrow keys to
select the “P” form of
phosphorus measurement.
183
Vial Adapter into the
cell holder.
Note: Place the grip tab at
the rear of the cell holder.
PHOSPHORUS, REACTIVE, continued
:30 seconds
5. Fill a PhosVer 3
Phosphate Reagent
AccuVac Ampul
with sample.
Note: Keep the tip
immersed while the ampul
fills completely.
6. Place an ampul cap
7. Press: SHIFT TIMER
securely over the tip of
A two-minute reaction
the ampul. Shake the
period will begin.
ampul for approximately
30 seconds. Wipe
off any liquid
and fingerprints.
Note: A blue color will form
if phosphate is present.
Note: Accuracy is
not affected by
undissolved powder.
9. Press: ZERO
The display will show:
Zeroing. . .
then:
0.00 mg/L P PV AV
10. Place the AccuVac
11. Press: READ
Ampul into the cell holder.
The display will show:
Note: Run a reagent blank
Reading. . .
for the test. Use
demineralized water in place then the result in mg/L P
of the sample in Step 3.
will be displayed.
Subtract this result from all
results with this lot of ampuls.
184
8. When the timer
beeps, the display will
show:
mg/L P PV AV
Place the zeroing vial
into the cell holder.
PHOSPHORUS, REACTIVE, continued
Sampling and Storage
Collect sample in plastic or glass bottles that have been cleaned with 1:1
Hydrochloric Acid Solution and rinsed with demineralized water. Do not
use commercial detergents containing phosphate for cleaning glassware
used in phosphate analysis.
Analyze samples immediately after collection for best results. If prompt
analysis is impossible, preserve samples for up to 48 hours by filtering
immediately and storing samples at 4 °C.
Accuracy Check
Standard Additions Method
a) Fill three 25-mL graduated mixing cylinders with 25 mL of sample.
b) Snap the neck off a Phosphate Voluette Ampule Standard Solution,
50 mg/L PO43-.
c) Use the TenSette Pipet to add 0.1 mL, 0.2 mL, and 0.3 mL of
standard, respectively, to the three mixing cylinders. Stopper each
and mix thoroughly.
d) For analysis with AccuVac Ampuls, transfer solutions to dry, clean
50 mL beakers to fill the vials. For analysis with powder pillows,
transfer only 10 mL of solution to the 10 mL sample cells.
e) Analyze each standard addition sample as described in steps 4 - 11
of the procedure. The phosphorus concentration, as read on the
spectrophotometer, should increase 0.067 mg/L P for each 0.1 mL
of standard added.
f) If these increases do not occur, see Standard Additions in Section I of the
DR/2010 Spectrophotometer Procedures Manual for more information.
Standard Solution Method
Prepare a 2.0 mg/L PO43- standard solution (0.67 mg/L as P) by
pipetting 4.0 mL of Phosphate Standard Solution, 50 mg/L as PO43-, into
a 100-mL volumetric flask. Dilute to volume with demineralized water.
Stopper and invert to mix. Use this solution in place of the sample in the
procedure to insure the accuracy of the test. The mg/L PO43- reading
should be 2.00 mg/L.
185
PHOSPHORUS, REACTIVE, continued
Interferences
• Large amounts of turbidity may cause inconsistent results in the phosphate
tests because the acid present in the powder pillow may dissolve some of
the suspended particles and because of variable desorption of
orthophosphate from the particles. For highly turbid or colored samples,
add the contents of one Phosphate Pretreatment Powder Pillow to 10 mL
of sample. Mix well. Use this solution to zero the instrument.
• The PhosVer 3 Phosphate Reagent Powder Pillows should be stored in
a cool, dry environment.
• The following may interfere when present in concentrations exceeding
these listed below:
Aluminum
200 mg/L
Chromium
100 mg/L
Copper
10 mg/L
Iron
100 mg/L
Nickel
300 mg/L
Silica
50 mg/L
Silicate
10 mg/L
Zinc
80 mg/L
• Arsenate and hydrogen sulfide do interfere.
• Highly buffered samples or extreme sample pH may exceed the buffering
capacity of the reagents and require sample pretreatment; see
Interferences, pH, in Section I of the DR/2010 Spectrophotometer
Procedures Manual.
Precision
In a single laboratory using a standard solution of 1.00 mg/L PO43- and
two lots of reagents with the DR/2010 Spectrophotometer, a single
operator obtained a standard deviation of ±0.01 mg/L PO43-.
In a single laboratory using a standard solution of 1.00 mg/L PO43- and two
representative lots of AccuVac Ampuls with the DR/2010 Spectrophotometer,
a single operator obtained a standard deviation of ±0.02 mg/L PO43-.
186
PHOSPHORUS, REACTIVE, continued
Estimated Detection Limit (EDL)
The EDL for program 490 is 0.01 mg/L PO43-. The EDL is the calculated
lowest average concentration in a demineralized water matrix that is
different from zero with a 99% level of confidence. For more information
on derivation and use of Hach’s estimated detection limit, see Section I of
the DR/2010 Spectrophotometer Procedures Manual.
The EDL for program 492 is 0.01 mg/L PO43-. The EDL is the calculated
lowest average concentration in a demineralized water matrix that is
different from zero with a 99% level of confidence. For more information
on derivation and use of Hach’s estimated detection limit, see Section I of
the DR/2010 Spectrophotometer Procedures Manual.
Summary of Method
Orthophosphate reacts with molybdate in an acid medium to produce a
Phosphomolybdate complex. Ascorbic acid then reduces the complex,
giving an intense molybdenum blue color.
REQUIRED REAGENTS (Using Powder Pillows)
Quantity Required
Per Test
Description
Unit
Cat. No.
PhosVer 3 Phosphate Reagent Powder Pillows
10 mL sample size .........................................................1 Pillow ............100/pkg .......21060-69
REQUIRED APPARATUS (Using Powder Pillows)
Cell Riser, 10-mL ................................................................ 1........................each .......45282-00
Sample Cell, 10 mL, matched pair...................................... 2.........................pair .......24954-02
REQUIRED REAGENTS (Using AccuVac Ampuls)
PhosVer 3 Phosphate Reagent AccuVac Ampuls...........1 ampul ..............25/pkg .......25080-25
REQUIRED APPARATUS (Using AccuVac Ampuls)
Adapter, AccuVac Vial ....................................................... 1 ........................each .......43784-00
Beaker, 50 mL .................................................................... 1 ........................each ...........500-41
Cap, ampul, blue ................................................................. 1 ....................25/pkg .........1731-25
Vial, zeroing ....................................................................... 1 ........................each .......21228-00
187
PHOSPHORUS, REACTIVE, continued
OPTIONAL REAGENTS
Description
Unit
Cat. No.
Hydrochloric Acid Standard Solution, 6.0 N (1:1) ..................................500 mL........... 884-49
Phosphate Pretreatment Powder Pillows .................................................. 50/pkg....... 14501-66
Phosphate Standard Solution, Voluette ampul,
50 mg/L as PO43-, 10 mL ..................................................................... 16/pkg........... 171-10
Phosphate Standard Solution, 50 mg/L as PO43- .......................................500 mL........... 171-49
Phosphate Standard Solution, 1 mg/L as PO43- .........................................500 mL......... 2569-49
Sodium Chloride, ACS ............................................................................... 454 g........... 182-01
Sodium Hydroxide Standard Solution, 5.0 N ..............................100 mL* MDB......... 2450-32
Water, demineralized ....................................................................................... 4 L........... 272-56
OPTIONAL APPARATUS
AccuVac Snapper Kit .................................................................................... each....... 24052-00
Cylinder, graduated, mixing, 25 mL, tall....................................................... each....... 20886-40
pH Indicator Paper, 1 to 11 pH ........................................................... 5 rolls/pkg ........... 391-33
pH Meter, EC10, portable .............................................................................. each....... 50050-60
Hach One Combination pH Electrode with Temp ......................................... each....... 48600-22
Pipet, 2 mL serological ................................................................................. each........... 532-36
Pipet, TenSette, 1.0 to 10.0 mL..................................................................... each....... 19700-10
Pipet Tips, for 19700-10 TenSette Pipet .................................................... 50/pkg...... 21997-96
Pipet Tips, for 19700-10 TenSette Pipet ................................................ 1000/pkg...... 21997-28
Pipet, TenSette, 0.1 to 1.0 mL TenSette Pipet ............................................... each....... 19700-01
Pipet Tips, for 19700-01 ........................................................................... 50/pkg....... 21856-96
Pipet Filler, safety bulb ................................................................................. each....... 14651-00
Spoon, measuring, 0.1 g ................................................................................ each........... 511-00
Thermometer, -10 to 110 °C .......................................................................... each......... 1877-01
OPTIONAL 25 ML ANALYSIS ITEMS
PhosVer 3 Phosphate Reagent Set for 25 mL samples (100 tests).................................. 2125-99
Pour-Thru Cell Assembly Kit (for 25 mL reagents only)............................. each...... 45215-00
Sample Cell, 25 ml matched pair................................................................... pair....... 20950-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
* Larger sizes available.
188
Method 8051
For water, wastewater, and seawater
SULFATE (0 to 70 mg/L)
SulfaVer® 4 Method* (Powder Pillows or AccuVac Ampuls),
USEPA accepted for reporting wastewater analysis**
Using Powder Pillows
450 nm
Choose Desired
Program Accuracy
1. A User-Entered
Calibration is necessary
to obtain the most
accurate results. See
User Calibration section
of this procedure.
Program 680 can be
used directly for
applications where a
high degree of accuracy
is not needed.
or
??
2. Enter the appropriate 3. Rotate the
stored program number wavelength dial until the
for sulfate (SO42-)
small display shows:
powder pillows.
450 nm
Press: 6 8 0 ENTER
When the correct
wavelength is dialed in
or
the display will quickly
9 ? ? ENTER
show: Zero Sample
The display will show:
then: mg/L SO42Dial nm to 450
Note: The nature of
Note: The Pour-Thru
turbidimetric tests and
cell cannot be used with
reagent lot variation
this procedure.
necessitate user calibration
for best results.
Note: For greater
accuracy, perform a user
calibration for each new lot
of SulfaVer 4 Sulfate
Reagent Powder Pillows;
see User Calibration
following these steps.
* Adapted from Standard Methods for the Examination of Water and Wastewater.
** Procedure is equivalent to USEPA method 375.4 for wastewater.
189
4. Fill a clean
sample cell with 25 mL
of sample.
Note: Filter highly turbid
or colored samples. Use
filtered sample in this step
and Step 7.
SULFATE, continued
5. Add the contents of
one SulfaVer 4 Sulfate
Reagent Powder Pillow
to the sample cell (the
prepared sample). Swirl
to dissolve.
6. Press: SHIFT TIMER 7. When the timer
A 5-minute reaction
period will begin.
Allow the cell to
stand undisturbed.
beeps, the display will
show: mg/L SO42Fill a second sample cell
with 25 mL of sample
(the blank).
A white turbidity
will develop if sulfate
is present.
Accuracy is not affected
by undissolved powder.
9. Press: ZERO
The display will show:
Zeroing. . .
then: 0. mg/L SO42-
10. Within five minutes
11. Press: READ
after the timer beeps,
The display will show:
place the prepared sample
into the cell holder. Close
Reading. . .
the light shield.
then the results in
mg/L SO42- will
be displayed.
Note: Clean the sample cells
with soap and a brush.
190
8. Place the blank into
the cell holder. Close the
light shield.
SULFATE, continued
Using AccuVac Ampuls
450 nm
or
Choose Desired
Program Accuracy
??
1. A User-Entered
2. Enter the appropriate
Calibration is necessary
to obtain the most
accurate results. See
User Calibration at the
back of this procedure.
Program 685 can be
used directly for process
control or applications
where a high degree of
accuracy is not needed.
stored program number
for sulfate (SO42-)
AccuVac Ampls.
Press: 6 8 5 ENTER
or
9 ? ? ENTER
The display will show:
3. Rotate the
4. Fill a zeroing vial (the
wavelength dial until the blank) with at least 10 mL
small display shows:
of sample. Collect at least
40 mL of sample in a
450 nm
50-mL beaker.
When the correct
Note: Filter highly turbid
wavelength is dialed, the or colored samples. Use
display will quickly
filtered sample in this
show: Zero Sample
step and Step 5.
then: mg/L SO42- AV
Dial nm to 450
Note: The nature of
turbidimetric tests and
reagent lot variation
necessitate user calibration
for best results.
5. Fill a SulfaVer 4
6. Quickly invert the
7. Press: SHIFT TIMER 8. Place the AccuVac
Sulfate AccuVac Ampul ampul several times to
Vial Adapter into the
A 5-minute reaction
with sample.
mix. Wipe off any liquid
cell holder.
period will begin.
or fingerprints.
Note: Keep tip
Note: Allow the ampul to
immersed until the ampul Note: A white turbidity will
stand undisturbed.
fills completely.
develop if sulfate is present.
Note: Accuracy is
not affected by
undissolved powder.
191
Note: Place the grip tab at
the rear of the cell holder.
SULFATE, continued
9. When the timer
10. Press: ZERO
beeps, the display
will show:
The display will show:
Zeroing. . .
mg/L SO42- AV
Place the blank into the
cell holder. Close the
light shield.
then:
0. mg/L SO42- AV
11. Within five minutes
12. Press: READ
after the timer beeps,
The display will show:
place the AccuVac Ampul
into the cell holder. Close
Reading. . .
the light shield.
then the results in mg/L
SO42- will be displayed.
Note: mg/L SO42- ÷ 48 =
meq/L SO42-
Sampling and Storage
Collect samples in clean plastic or glass bottles. Samples may be stored up to
28 days by cooling to 4 °C (39 °F) or lower. Warm to room temperature
before analysis.
Accuracy Check
Standard Additions Method
a) Fill three 25-mL graduated mixing cylinders with 25 mL of sample.
b) Snap the neck off a Sulfate Voluette Ampule Standard Solution,
2500 mg/L SO42- .
c) Use a TenSette Pipet to add 0.1, 0.2 and 0.3 mL of standard to the
three 25-mL samples. Mix thoroughly. For AccuVac Ampuls,
transfer to clean, dry 50-mL beakers.
d) Analyze each sample as described above. The sulfate
concentration should increase 10 mg/L for each 0.1 mL of
standard added.
e) If these increases do not occur, see Standard Additions in
Section I of the DR/2010 Spectrophotometer Procedures
Manual for more information.
192
SULFATE, continued
Standard Solution Method
Check the accuracy of the test by using the Sulfate Standard Solution,
50 mg/L, listed under Optional Reagents. Or, prepare this solution by
pipetting 1.0 mL of the contents of a Voluette Ampule Standard for
Sulfate (2500 mg/L) into a 50-mL volumetric flask. Dilute to volume
with demineralized water.
Substitute this standard for the sample and proceed with the test as
described in the procedure. The mg/L SO42- reading should be 50 mg/L.
User Calibration
For most accurate results, the use of a user-calibrated program is highly
recommended. The Hach stored programs 680 and 685 are intended for
process control samples or other applications where a high degree of
accuracy is not necessary.
A one-time setup program for sulfate is required. A sulfate program
template is pre-programmed into memory to make the process easier.
After the setup is complete, the calibration can be entered for each new lot
of reagents used or as necessary.
Standard Preparation
A new calibration should be performed for each new lot of SulfaVer 4
Sulfate Reagent as follows:
Prepare standards of 10, 20, 30, 40, 50, and 60 mg/L sulfate by pipetting 1,
2, 3, 4, 5, and 6 mL of a 1000-mg/L Sulfate Standard Solution into 100-mL
volumetric flasks. Dilute to the mark with demineralized water. Mix well.
Initial Setup of Sulfate Program
The templates within User Program cannot be run directly. They must be
copied into a usable program number (greater than 950) as in step c and d.
Then, calibrate the program. The preprogrammed calibration (680 or 685)
may be suitable for process control.
a) Press SHIFT USER PRGM. Use the UP arrow key to scroll to Copy
Program. Press ENTER.
b) Scroll to or enter the template number for sulfate [906, 907 (AV)].
Press ENTER.
c) Scroll to or enter the desired user program number for sulfate
(>950). Press ENTER. Record the program number for reference.
d) The display will show: Program Copied. Press EXIT. The program
is now ready to be calibrated.
193
SULFATE, continued
User Calibration of Sulfate Program
a) Use the test procedure to develop color in the standards just before
recording the absorbance values for the calibration.
b) Press SHIFT USER PRGM. Use the UP arrow to scroll to Edit
Program. Press ENTER.
c) Scroll to or enter the program number for sulfate (from step c in
Setup). Press ENTER.
d) Rotate the wavelength dial until the small display shows 450 nm.
e) Scroll down to Calibration Table. Press ENTER. The first
concentration point will be displayed.
f) Press ENTER to display the absorbance value of the first
concentration point. Place the blank solution in the cell holder.
Close the light shield. Press ZERO.
g) Place the first developed standard solution (10 mg/L SO42-) in the
cell holder. Close the light shield. Press ENTER to accept the
absorbance reading.
h) The second concentration point will be displayed. Press ENTER to
display the stored absorbance value of the second concentration.
Place the second developed standard solution (20 mg/L sulfate) in
the cell holder. Close the light shield. Press READ to display the
absorbance value of the standard solution.
i) Press ENTER to accept the absorbance reading. The next
concentration point will then be displayed.
j) Repeat steps g and h as necessary for the remaining standards.
There are 6 standards in addition to the blank.
k) When finished reading the absorbance values of the standards, press
EXIT. Scroll down to Force Zero. Press ENTER to change the setting.
Change to ON by pressing the arrow key, then press ENTER.
l) Scroll down to Calib Formula. Press ENTER twice or until only the
0 in F(0) is flashing. Press DOWN arrow to select F3 (cubic
calibration). Press ENTER to select F3.
Note: Alternative
calibration fits
may also be used
if appropriate.
m) Press EXIT twice. The display will show Store Changes?. Press
ENTER to confirm.
n) Press EXIT. The program is now calibrated and ready for use. Start
with step 2 of the iconed test procedure.
194
SULFATE, continued
Precision
In a single laboratory, using a standard solution of 50 mg/L sulfate and two
representative lots of powder pillows with the DR/2010 Spectrophotometer,
a single operator obtained a standard deviation of ±0.9 mg/L sulfate.
In a single laboratory, using a standard solution of 50 mg/L sulfate and two
representative lots of AccuVac Ampuls with the DR/2010 Spectrophotometer,
a single operator obtained a standard deviation of ±2.2 mg/L sulfate.
Estimated Detection Limit (EDL)
The EDL for program 680 is 7 mg/L SO42-. The EDL is the calculated
lowest average concentration in a demineralized water matrix that is
different from zero with a 99% level of confidence. For more information
on derivation and use of Hach’s estimated detection limit, see Section I of
the DR/2010 Spectrophotometer Procedures Manual.
The EDL for program 685 is 7 mg/L SO42-. The EDL is the calculated
lowest average concentration in a demineralized water matrix that is
different from zero with a 99% level of confidence. For more information
on derivation and use of Hach’s estimated detection limit, see Section I of
the DR/2010 Spectrophotometer Procedures Manual.
Interferences
The following interfere at levels above those concentrations listed:
Calcium
20,000 mg/L as CaCO3
Chloride
40,000 mg/L as Cl-
Magnesium
10,000 mg/L as CaCO3
Silica
500 mg/L as CaCO3
Summary of Method
Sulfate ions in the sample react with barium in the SulfaVer 4 Sulfate
Reagent and form insoluble barium sulfate turbidity. The amount of
turbidity formed is proportional to the sulfate concentration.
195
SULFATE, continued
REQUIRED REAGENTS (Using Powder Pillows)
Quantity Required
Per Test
Description
Units
Cat. No.
SulfaVer 4 Sulfate Reagent Powder Pillows .................. 1 pillow............ 100/pkg....... 12065-99
REQUIRED REAGENTS (Using AccuVac Ampuls)
SulfaVer 4 Sulfate AccuVac Ampuls ............................. 1 ampul.............. 25/pkg....... 25090-25
REQUIRED APPARATUS (Using Powder Pillows)
Sample Cell, 25 mL, matched pair ......................................2 ....................... each....... 20950-00
Brush....................................................................................1 ....................... each........... 690-00
REQUIRED APPARATUS (Using AccuVac Ampuls)
Adapter, AccuVac Vial.........................................................1 ....................... each....... 43784-00
Beaker, 50-mL .....................................................................1 ....................... each........... 500-41
Vial, zeroing.........................................................................1 ....................... each....... 21228-00
OPTIONAL REAGENTS
Sulfate Standard Solution, 50 mg/L..........................................................500 mL......... 2578-49
Sulfate Standard Solution, 1000 mg/L......................................................500 mL....... 21757-49
Sulfate Standard Solution, Voluette Ampule, 2500 mg/L, 10 mL ............. 16/pkg....... 14252-10
Water, demineralized ........................................................................................ 4L........... 272-56
OPTIONAL APPARATUS
AccuVac Snapper Kit..................................................................................... each....... 24052-00
Ampule Breaker Kit....................................................................................... each....... 21968-00
Cylinder, Graduated Mixing, 25 mL.............................................................. each....... 20886-40
Filter Paper, folded, 12.5 cm.................................................................... 100/pkg......... 1894-57
Flask, volumetric, 50 mL, Class A ................................................................ each....... 14574-41
Flask, volumetric, 100 mL, Class A .............................................................. each....... 14574-42
Funnel, poly, 65 mm ...................................................................................... each......... 1083-67
Pipet, TenSette, 0.1 to 1.0 mL........................................................................ each....... 19700-01
Pipet, Tips, for 19700-01 Pipet .................................................................. 50/pkg....... 21856-96
Pipet, Volumetric, 1.00 mL, Class A ............................................................. each....... 14515-35
Pipet, Volumetric, 2.00 mL, Class A ............................................................. each....... 14515-36
Pipet, Volumetric, 3.00 mL, Class A ............................................................. each....... 14515-03
Pipet, Volumetric, 4.00 mL, Class A ............................................................. each....... 14515-04
Pipet, Volumetric, 5.00 mL, Class A ............................................................. each....... 14515-37
Pipet, Volumetric, 6.00 mL, Class A ............................................................. each....... 14515-06
Pipet, Filler, saftey bulb ................................................................................. each....... 14651-00
For technical support and ordering information, see General Information section.
In the U.S.A. call 800-227-4224 to place an order.
Outside the U.S.A.—Contact the Hach office or distributor serving you.
196
SECTION 7
7.1
SODIUM ESTIMATION AND
SODIUM ADSORPTION RATIO CALCULATIONS
Na meq/L for Irrigation Water
7.1.1 Procedure
1. Determine the concentration of total soluble salts in meq/L by dividing
the conductivity µS/cm by 100.
Note: Refer to SECTION 6 IRRIGATION WATER PROCEDURES,
CONDUCTIVITY.
2. Determine the Ca + Mg (meq/L) by the EDTA Titration Method.
Note: Refer to SECTION 6 IRRIGATION WATER PROCEDURES,
HARDNESS, TOTAL.
3. Subtract the value in Step 2 from the value in Step 1. This is the
estimated sodium in meq/L.
conductivity
Sodium Estimation =  -------------------------------  – ( calcium + magnesium )


100
7.1.2 Sample Calculations
a) A water sample has a conductivity of 1250 µS/Cm and the
calcium + magnesium equals 8.6 meq/L.
b) sodium Est. (meq/L) = 1250
------------- – 8.6 = 3.9 meq/L
100
Est. (meq/L)
3.9
------------------------------------------------------ = -----------c) SAR = Sodium
Ca + Mg (meq/L)
--------------------------------------------2
3.9
= ------------ = 3.9 ÷ 2.07 = 1.9
4.3
197
8.6
-------2
198
GENERAL INFORMATION
At Hach Company, customer service is an
important part of every product we make.
With that in mind, we have compiled the following
information for your convenience.
199
200
HOW TO ORDER
By Phone:
6:30 a.m. to 5:00 p.m. MST
Monday through Friday
800-227-HACH (800-227-4224)
By Mail:
Hach Company World Headquarters
P. O. Box 389
Loveland, Colorado 80539-0389 U.S.A.
By FAX:
970-669-2932 (Hach Loveland)
Information Required:
• Hach account number (if available)
• Billing address
• Shipping address
• Your name and phone number
• Purchase order number
• Catalog number
• Brief description or model number
• Quantity
Technical and Customer Service
Hach Technical and Customer Service Department personnel are eager to
answer questions about our products and their use and to take your orders.
Specialists in analytical methods, they are happy to put their talents to
work for you. Call 1-800-227-4224.
201
HOW TO ORDER, continued
International Customers:
Hach maintains a network of dealers and distributors throughout the
world.
In Canada
Hach Sales and Service Canada Ltd.
1313 Border Street, Unit 34
Winnipeg, Manitoba R3H 0X4
Telephone: (204) 632-5598
FAX: (204) 694-5134
Hach Company World Headquarters
P. O. Box 389
Loveland, Colorado, U.S.A. 80539-0389
Telex: 160840
Telephone: (1) (970) 669-3050
FAX: (1) (970) 669-2932
Information presented on these pages applies only to Hach products
manufactured for use within the United States. Exportation of these
products renders these terms void.
Prices and Terms
Prices are subject to change without notice. All prices are FOB from the
shipping point (usually Ames, Iowa). Hach offers instant credit up to $200
on Net 30 Day terms. Larger orders are subject to credit review. Customers
may send remittance with orders or we can ship C.O.D. if preferred.
Warranty
Hach warrants its products to be of high quality, to be free of material
defects on the date of shipment and to be as specified. Full warranty
information is on the back of Hach invoices.
202
HOW TO ORDER, continued
Limits of Usage
Our chemicals and reagents are offered for laboratory and manufacturing
use ONLY. They may not be used as drugs, cosmetics or food additives.
MSDS
Hach Material Safety Data Sheets, among the most complete and
informative in the industry, provide comprehensive safety data essential
for day-to-day operations and safety training.
An MSDS accompanies all Hach chemical products including test kits.
For an additional $15.00 per item, we will print MSDSs on your own
forms.
Label Information
Labels on Hach chemicals and reagents supply the following:
• Product Name -- In French, German, Italian and Spanish as well as
English is printed on all but the smallest-size labels.
• Hach Catalog Number -- Makes reordering easy and helps match the
appropriate MSDS.
• Storage Information and Lot Numbers -- Lot numbers made up of
letters and numbers indicate an extended shelf life; a four-digit number
indicates items should be rotated and checked with a standard to
confirm performance. The lot number is essential if you call for
technical assistance or with questions about reagent performance.
Shipping
Our experienced warehouse staff packages your orders for safe arrival.
Unless we are instructed otherwise, the best and most efficient mode of
transportation is selected. Motor freight shipments will be sent freight
collect unless you specify otherwise at the time you order.
If you have questions about methods for shipment and availability of
special packaging, please ask when you place your order.
203
HOW TO ORDER, continued
Claims and Returns
We take extreme care to fill, check, re-check and pack orders properly. If
errors or damages should occur, please report details to our Loveland
Customer Service Department and to the carrier immediately. Be sure to
keep all containers and packing materials.
AUTHORIZATION MUST BE OBTAINED from Hach when returning
items for any reason. Call 1-800-227-4224 toll free. ALL “FREIGHT
COLLECT” SHIPMENTS OR MERCHANDISE RETURNED
WITHOUT PROPER AUTHORIZATION FROM HACH WILL BE
REFUSED.
Trademarks of Hach Company
AccuVac®
AluVer®
BariVer®
BoroVer®
CalVer®
ChromaVer®
CuVer®
CyaniVer®
Digesdahl®
DithiVer®
FerroVer®
FerroZine®
Hach Logo®
Hach One®
HexaVer®
LeadTrak®
ManVer®
MolyVer®
NitraVer®
NitriVer®
PermaChem®
PhosVer®
PocketPal™
PourRite™
Ratio™
RoVer®
StablCAL™
StillVer®
SulfaVer®
TanniVer®
TenSette®
Test ‘N Tube™
TitraStir®
TitraVer®
ToxTrak
UniVer®
Voluette®
ZincoVer®
Newsletter
News & Notes for the Analyst, Hach’s informative newsletter, contains
updates on federal regulations, in-depth discussions of chemical
reactions, application notes and information about new products. Contact
Hach for your free subscription.
204
MAIL ORDER FORM
If Hach account
number is not
known, leave the
space blank.
Most chemicals
and apparatus are
sold separately
(“each”), but
others are sold in
units. Powder
pillows, for
example, are
available in
packages of 100.
To purchase 100
powder pillows,
order 1 unit, not
100 pillows. Be
sure to order the
number of units
(packages) you
need.
Include all
numbers given in
the products
listing.
A one- or two-word
description of the
item.
If more than one
size of an item is
offered, state the
size you want.
Your shipping
charge goes here.
Figure your
simplified freight
fee using the
information in
“Simplified Freight
Charges” on the
preceding pages.
Check one box.
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must be
substantiated with
documentation
identifying your tax
exempt number. If
taxable, sales tax
will be added to
Send order to: HACH COMPANY, P.O. Box 608, Loveland, CO 80539-0608
Use this convenient form, your own purchase orders, or for PROMPT PHONE
SERVICE CALL 1-800-227-4224. If ordering by phone, please have information
related to items 1 - 4 (below) ready.
Check box if “Ship To” information is identical to “Bill To”.
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ATTENTION
PHONE NO. ( ___________) ________________________ EXTENSION ___________
COMPANY
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207
HACH COMPANY
WORLD HEADQUARTERS
P.O. Box 389
Loveland, Colorado 80539-0389
Telephone: (970) 669-3050
FAX: (970) 669-2932
FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:
In the U.S.A. - Call toll-free 800-227-4224
Outside the U.S.A. - Contact the HACH office or distributor serving you.
On the Worldwide Web - www.hach.com; E-mail - techhelp@hach.com
208

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