User's Guide
Brix Refractometers
Models RF10 and RF15 (with ATC)
Introduction
Congratulations on your purchase of the Extech RF10 or RF15 Brix
Refractometer. Precision optical instruments should be handled gently; avoid touching the optical surface. Careful use of these instruments will provide years of reliable service.
Specifications
Range 0 to 32% Brix
Resolution 0.2%
Dimensions RF10: 6.6 x 1.3 x 1.3" (168 x 32 x 32mm);
RF15: 6.3 x 1.4 x 1.4" (159 x 35 x 35mm)
Weight RF10: 3.2 oz. (91g); RF15: 7 oz. (200g)
Description
1. Eyepiece 3 2
5
4
1
5. Prism
Operation
This instrument measures the refractive index of a sample. The measurement is displayed in % Brix.
1. Zero Adjustment
Cover the prism with distilled water (several drops will suffice). Close the cover plate and rotate the adjustment screw until the light/dark boundary
(shadowline) lines up with the zero line. After the zero adjustment, clean the prism with a soft cloth.
2. Sample Preparation and Reading
To take a sample reading, simply place a few drops of a sample liquid on the measurement prism at the end of the instrument. Close the prism cover plate so that the liquid spreads across the entire surface of the prism without air bubbles or dry spots (see diagram). Allow the sample to remain on the prism for approximately 30 seconds.
While holding the instrument under a light source, look through the eyepiece. The sucrose concentration is determined by the intersection of the boundary of the light and dark fields (known as the shadowline) on
Bad Bad Good the printed scale. If the scale appears out of focus, the eyepiece may be adjusted by rotating the knurled portion of the eyepiece. The instrument also features an eye-guard to prevent stray light from entering the eyepiece and causing reflections.
It may be necessary to adjust the position of the light source to maximize the contrast of the shadowline. Under normal conditions, optimal contrast is obtained by holding the instrument underneath and perpendicular to a light source.
Once a reading has been taken, wipe dry with a clean cloth (do not wash or rinse) and place the instrument in the supplied plastic case. Store the instrument in a safe, dry environment.
Note: The Distilled water temperature, used for zero adjustment, and the sample liquid temperature should be the same. If the temperature of the samples fluctuates, zero the refractometer every 30 minutes (RF10 only).
3. Temperature Compensation (RF15 has Auto Temp. Comp.)
Temperature is one of the single most important factors influencing accurate refractometer readings and is one of the largest sources of measurement error. Temperature compensation relieves the user of the responsibility to measure temperature and apply a correction factor when taking readings. The RF15 makes this correction automatically. When ambient temperature strays from 68°F (20°C), readings are automatically adjusted to compensate for temperature variance between 50°F to 86°F
(10°C to 30°C).
The RF10 Refractometer has been designed for use with a 20°C standard temperature. Therefore, if the temperature of the measurement deviates from 20°C, the reading must be manually compensated in accordance with the Temperature Compensation Table below.
Example: A reading of 20% at 28°C is compensated thusly: 20% +
0.62%=20.62%.
Copyright © 2005 Extech Instruments Corporation.
All rights reserved including the right of reproduction in whole or in part in any form.
Temperature Compensation Table (Referenced To 20
O
C) o
% 5 10 15 20 25 30 35 40 45 50 55 60 65 70
C Subtract the following from the measurement
10 0.58 0.59 0.61 0.64 0.67 0.69 0.71 0.72 0.74 0.74 0.74 0.75 0.76 0.77
11 0.51 0.54 0.55 0.58 0.61 0.63 0.65 0.65 0.67 0.67 0.67 0.68 0.68 0.69
12 0.47 0.49 0.50 0.52 0.55 0.57 0.58 0.58 0.60 0.60 0.60 0.60 0.61 0.61
13 0.42 0.44 0.44 0.45 0.49 0.50 0.51 0.51 0.53 0.53 0.53 0.53 0.53 0.53
14 0.37 0.38 0.39 0.40 0.42 0.43 0.44 0.44 0.45 0.45 0.45 0.45 0.45 0.46
15 0.31 0.32 0.33 0.34 0.35 0.36 0.37 0.37 0.38 0.38 0.38 0.38 0.38 0.38
16 0.25 0.26 0.27 0.28 0.28 0.29 0.30 0.30 0.30 0.31 0.31 0.31 0.31 0.31
17 0.19 0.20 '0.20 0.21 0.21 0.22 0.22 0.23 0.23 0.23 0.23 0.23 0.23 0.23
18 0.13 0.13 0.14 0.14 0.14 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15
19 0.06 0.07 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
Add the following to the measurement
21 0.07 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
22 0.14 0.14 0.14 0.14 0.15 0.15 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.15
23 0.21 0.21 0.22 0.22 0.23 0.23 0.23 0.23 0.24 0.24 0.24 0.24 0.23 0.22
24 0.28 0.29 0.29 0.30 0.30 0.31 0.31 0.31 0.31 0.31 0.32 0.32 0.31 0.31
25 0.35 0.36 0.37 0.38 0.38 0.39 0.39 0.40 0.40 0.40 0.40 0.40 0.39 0.39
26 0.43 0.44 0.44 0.46 0.46 0.47 0.47 0.48 0.48 0.48 0.48 0.48 0.47 0.47
27 0.51 0.52 0.53 0.54 0.55 0.55 0.56 0.56 0.56 0.56 0.56 0.56 0.55 0.55
28 0.59 0.60 0.61 0.62 0.63 0.64 0.64 0.65 0.65 0.64 0.64 0.64 0.64 0.63
29 0.67 0.68 0.69 0.70 0.71 0.72 0.73 0.73 0.73 0.73 0.73 0.72 0.72 0.71
30 0.75 0.77 0.78 0.79 '0.80 '0.81 0.81 0.81 0.82 0.81 0.81 0.81 0.80 0.79
Source: International Commission for Uniform Methods of Sugar Analysis (1966)
International Brix% Scale
Brix to Refractive Index (nD) Conversion Table
% nD % nD % nD % nD % nD % nD
0 1.333 15 1.3557
30 1.3811
45 1.4097
60 1.4419
75 1.4778
1 1.3344
16 1.3573
31 1.3829
46 1.4118
61 1.4442
76 1.4804
2 1.3359
17 1.3589
32 1.3847
47 1.4138
62 1.4464
77 1.4829
3 1.3373
18 1.3605
33 1.3866
48 1.4159
63 1.4488
78 1.4855
4 1.3388
19 1.3622
34 1.3884
49 1.418 64 1.4511
79 1.4881
5 1.3403
20 1.3638
35 1.3903
50 1.42 65 1.4534
80 1.4907
6 1.3418
21 1.3655
36 1.3922
51 1.4222
66 1.4558
81 1.4933
7 1.3433
22 1.3672
37 1.3941
52 1.4243
67 1.4582
82 1.496
8 1.3448
23 1.3689
38 1.396 53 1.4264
68 1.4606
83 1.4987
9 1.3463
24 1.3706
39 1.3979
54 1.4286
69 1.463 84 1.5014
10 1.3478
25 1.3723
40 1.3998
55 1.4308
70 1.4654
85 1.5041
11 1.3494
26 1.374 41 1.4018
56 1.4329
71 1.4678
86 1.5068
12 1.3509
27 1.3758
42 1.4037
57 1.4352
72 1.4703
87 1.5096
13 1.3525
28 1.3776
43 1.4057
58 1.4374
73 1.4728
88 1.5123
14 1.3541
29 1.3793
44 1.4077
59 1.4396
74 1.4753
89 1.5151
Source: International Sugar Analysis Committee
Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment (a six month limited warranty applies on sensors and cables). If it should become necessary to return the instrument for service during or beyond the warranty period, contact the Customer Service Department at (781) 890-7440 ext. 210 for authorization or visit our website at www.extech.com (click on ‘Contact Extech’ and go to ‘Service
Department’ to request an RA number). A Return Authorization (RA) number must be issued before any product is returned to Extech. The sender is responsible for shipping charges, freight, insurance and proper packaging to prevent damage in transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper wiring, operation outside of specification, improper maintenance or repair, or unauthorized modification. Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct, indirect, incidental or consequential damages. Extech's total liability is limited to repair or replacement of the product. The warranty set forth above is inclusive and no other warranty, whether written or oral, is expressed or implied.
Manual Version No. 2.1
November 2005
