Technical Note: Analytical Repeatability, Accuracy, and Robustness of Instant Connect GC Modules

Technical Note: Analytical Repeatability, Accuracy, and Robustness of Instant Connect GC Modules
Fausto Pigozzo and Paolo Magni, Thermo Fisher Scientific, Milan, Italy
Te ch ni cal N ote 5 2 3 6 4
Analytical Repeatability, Accuracy,
and Robustness of Instant Connect
GC Modules
Key Words
TRACE 1300 Series GC, Instant Connect modules, SSL, PTV, FID, ECD,
TCD, NPD
Introduction
GC injectors and detectors are considered fundamental
components of a gas chromatography system. In modern
instrumentation, they consist of the mechanical parts, the
inner body with all tubing for gas connections, pneumatics,
and electronic controls. Selection of an appropriate injector
and detector is based on application requirements. Changing
a system configuration to follow a new analytical need or
application is a complex operation, requiring specialized
service assistance and often resulting in a new system
requirement.
The Thermo Scientific™ TRACE™ 1300 Series GC is the
first GC instrument on the market that has transcended
this design model. Similar to the long-established
modularity in HPLC, it makes the fundamental instrument
components (the injector and detector) available as
independent sub-systems, which are combined to produce
the desired analytical layout. The level of modularity of
the TRACE 1300 Series GC allows users to rapidly adapt
the instrument configuration to new application and/or
workload requirements without consulting a service
engineer.
This new GC modularity is implemented in the TRACE 1300
Series GC in the form of a full range of injector and
detector modules, which are easy and quick to install and
swap. These modules, termed Instant Connect, incorporate
all relevant pneumatic hardware and electronic parts
necessary for making the injector or the detector a fully
self-sufficient sub-unit of the instrument. All electronic
circuits and pneumatic controls are integrated into the
injector body or detector cell, and enclosed into a light,
17 cm x 10 cm x 6 cm, easy-to-handle housing. Each
module stores all specific electronic and pneumatic
calibration information, minimizing module-to-module
performance variation. The modules are plugged into the
top part of the GC, are automatically configured into the
system, and connected to the gas supply lines. Installing a
module takes only two minutes: the time needed to fix
three retaining screws and slide the new injector or
detector module in place.
Laboratories can benefit from the versatility provided by
this “Instant Connect” modularity in several ways:
• Expanding instrument capability at any time, by adding
a new injector or detector module to run a new method
• Upgrading a GC from single to multiple channels to
satisfy rapid incremental business needs and enhance
laboratory productivity
• Replacing contaminated injectors or detectors quickly
with clean ones and running samples in a few minutes,
while conducting full maintenance and cleaning when
the laboratory schedule allows
• Sharing injectors and detectors with different
TRACE 1300 Series GC units in a lab depending
on the application
The list of “Instant Connect” modules includes Split/
Splitless (SSL) and Programmable Temperature Vaporizing
(PTV) injectors both in the standard and backflush
configuration and all standard GC detectors: Flame
Ionization Detector (FID), Electron Capture Detector
(ECD), Thermal Conductivity Detector (TCD), and
Nitrogen Phosphorous Detector (NPD).
2
This technical note describes results obtained from an
endurance mechanical test performed on “Instant Connect”
modules and typical analytical reproducibility and
accuracy provided by the TRACE 1300 Series GC.
Analytical reproducibility was also measured after switching
modules of the same type in the same application, as
might happen when an injector module is replaced with a
new one in a routine laboratory to keep a contaminated
instrument up and running.
Experimental
A TRACE 1310 GC instrument equipped with various
SSL and FID modules was used in all of the experiments,
and all “Instant Connect” modules are identified by specific
serial numbers for easier tracking in the lab. Four different
modules were alternated in these experiments.
The GC was equipped with a Thermo Scientific AS 1310
liquid autosampler. All tests were performed using a
synthetic mix of normal alkanes ranging from C10 to C40
in hexane, at a concentration of approximately 10 ppm
(10 ng/μL) and using helium as carrier gas. A 1 μL aliquot
of sample was injected in splitless mode into a standard
glass-wool packed tapered liner, while the injector
temperature was maintained at 300 °C. Splitless time
was 0.8 minutes. The FID detector temperature was set
to 350 °C.
Results and Discussion
System analytical reproducibility and accuracy
The analytical reproducibility was evaluated using two
new “Instant Connect” modules, a SSL injector
(module serial number S/N: 712100036) and a FID
detector (S/N: 712300088), by injecting the synthetic
hydrocarbon mix automatically (ten repetitions). Results in
terms of peak area and retention time repeatability are
summarized in Tables 1 and 2. No discrimination for both
volatile and high boiling compounds was seen. As shown
in Table 1 the recovery, calculated using C20 peak area as
reference, is close to 100% along the full range of
volatility. Absolute peak area relative standard deviation
is far below 1% for all hydrocarbons. All injector and
detector modules incorporate a new generation of
miniaturized gas controls. These integrated electronic
devices ensure precise control of the inlet pressure and the
flow throughout the column, further contributing to the
excellent reproducibility of retention times. As indicated
in Table 2, the standard deviation is below a thousandth of
a minute. This level of reproducibility is a clear indication
of the accurate temperature profile and column flow
maintained during the ramp and the precise thermoregulation of the GC oven. Overall results show full
recovery of hydrocarbons and excellent data precision.
A Thermo Scientific TraceGOLD™ column TR-5, 15 m x
0.25 mm id x 0.25 μm, was used in all experiments. Oven
temperature was set at 50 °C for 0.5 min and then ramped
up to 340 °C at 20 °C/min, with two minutes of isothermal
time at the final temperature. A Thermo Scientific Dionex™
Chromeleon™ Chromatography Data System was used for
setting all method parameters, data acquisition, and data
processing.
Table 1. Instrument configuration SSL S/N 712100036 and FID S/N 712300088. Absolute peak area RSD% far lower than 1%. Recovery,
measured as ratio vs C20 average area, at 100% for the whole range of hydrocarbons
SSL 712100036
/ FID 712300088
nC10
nC12
nC14
nC16
nC18
nC20
nC22
nC24
3
Module-to-module reproducibility
To simulate a situation where a laboratory needs to quickly
replace a module, such as to avoid interrupting instrument
throughput for maintenance, the “Instant Connect” SSL
injector module (S/N: 712100036) was replaced by a new
module (S/N: 712300021). This required cooling and
powering down the instrument, disconnecting the column
from the original SSL injector module, removing the module
and plugging in the new one, connecting the column, and
powering up the TRACE 1310 GC again. Electronic gas
control permits an automated leak check to be performed
to guarantee that no artifacts are introduced by this
manual operation. The reduced thermal mass GC design
allows a quick recovery of injection-ready conditions after
instrument power-up. As a result, the GC was ready to
resume analytical injections again in only nine minutes
after it was originally powered down. A blank GC cycle
was programmed before injecting samples again, which is
good practice to ensure the entire flow path was not
affected by air introduced during module replacement.
An automated sequence of 10 injections was performed
immediately after the module replacement along with
collecting data. The instrument was then stopped again,
and the FID detector module (S/N: 712300088) was
replaced by a new one (S/N: 712300126). After a blank
run, another sequence of 10 injections completed the
experiments. Tables 3 and 4 and Figure 1 summarize the
repeatability results for the three different instrument
configurations. Variations in peak area measured as a
delta of the average counts are in the range of a few
percentages when changing either the injector or the FID
detector. Such a variation, for many applications, is well
below the required limit of a system suitability check,
eliminating the need to recalibrate the GC system as a
whole. The retention time variations are in the range of a
few hundredths of a minute or even less with no impact
on component retention time.
nC26
nC28
nC30
Figure 1. Module-to-module repeatability. Modules store all
of their calibration information allowing minimum variation if
replaced on a system.
nC32
nC34
nC36
nC38
nC40
Injection 1
2600304
2647767
2600941
2619188
2552750
2565809
2543886
2535687
2512699
2527008
2602759
2597807
2534441
2564855
2470270
2525384
Injection 2
2610605
2657856
2601653
2623404
2568557
2579380
2565938
2565679
2545232
2560614
2636265
2629734
2557462
2596729
2495209
2563483
Injection 3
2602666
2653832
2599714
2626029
2553641
2577265
2561577
2558672
2542703
2555406
2632496
2630095
2555743
2580475
2480864
2538819
Injection 4
2636572
2683702
2632897
2656448
2593709
2602685
2584957
2575384
2558834
2574920
2649582
2640082
2566623
2593858
2490053
2549873
Injection 5
2623737
2668679
2617130
2639475
2575209
2588255
2568857
2566489
2551218
2570336
2641759
2632243
2559472
2591033
2487269
2545848
2560371
Injection 6
2628675
2671731
2625320
2647746
2586155
2602674
2584119
2578956
2563433
2577945
2652932
2644762
2572449
2600568
2495549
Injection 7
2633245
2675436
2621623
2640507
2579749
2601553
2603546
2589030
2566470
2580193
2651340
2644782
2575086
2615870
2515378
2552861
Injection 8
2622426
2667773
2618401
2631007
2571368
2588047
2571982
2568771
2543992
2565899
2635937
2628421
2556233
2599156
2491820
2552234
Injection 9
2627383
2675413
2624978
2646945
2578061
2590137
2578171
2582555
2553973
2565982
2637795
2636002
2561603
2598494
2504800
2575965
Injection 10
2621650
2664829
2611668
2634863
2576839
2592681
2577082
2571091
2552087
2567396
2634338
2631176
2560023
2590260
2497076
2558360
Average (counts)
2620726
2666702
2615432
2636561
2573604
2588848
2574011
2569231
2549064
2564570
2637520
2631510
2559913
2593130
2492829
2552320
SD
12355
10941
11571
11889
12894
12092
15913
14767
15078
15223
14298
13319
11161
13430
12358
13908
RSD %
0.47%
0.41%
0.44%
0.45%
0.50%
0.47%
0.62%
0.57%
0.59%
0.59%
0.54%
0.51%
0.44%
0.52%
0.50%
0.54%
Recovery %
101%
103%
101%
102%
99%
100%
99%
99%
98%
99%
102%
102%
99%
100%
96%
99%
4
5
Table 2. Retention time standard deviation in the range of 1/1000 minute
nC10
nC12
nC14
nC16
nC18
nC20
nC22
nC24
nC26
nC28
nC30
nC32
nC34
nC36
nC38
nC40
Injection 1
2.562
3.935
5.253
6.445
7.525
8.506
9.408
10.237
11.005
11.717
12.385
13.010
13.598
14.153
14.680
15.190
Injection 2
2.562
3.933
5.252
6.445
7.525
8.508
9.408
10.237
11.005
11.718
12.385
13.010
13.598
14.153
14.678
15.188
Injection 3
2.562
3.933
5.252
6.445
7.523
8.505
9.407
10.233
11.003
11.715
12.383
13.007
13.597
14.152
14.680
15.189
Injection 4
2.562
3.935
5.253
6.445
7.525
8.508
9.408
10.237
11.005
11.718
12.385
13.008
13.598
14.152
14.678
15.188
Injection 5
2.562
3.933
5.252
6.445
7.525
8.508
9.408
10.237
11.003
11.717
12.385
13.010
13.600
14.154
14.678
15.191
Injection 6
2.562
3.933
5.252
6.445
7.525
8.508
9.408
10.237
11.005
11.717
12.385
13.010
13.598
14.153
14.680
15.189
Injection 7
2.562
3.933
5.252
6.447
7.525
8.507
9.407
10.237
11.003
11.718
12.385
13.008
13.597
14.153
14.681
15.190
Injection 8
2.562
3.933
5.252
6.445
7.525
8.507
9.408
10.235
11.003
11.717
12.385
13.008
13.598
14.150
14.680
15.190
Injection 9
2.560
3.932
5.250
6.443
7.523
8.506
9.408
10.235
11.002
11.717
12.385
13.008
13.597
14.153
14.682
15.191
Injection 10
2.562
3.933
5.252
6.445
7.525
8.508
9.408
10.237
11.005
11.718
12.385
13.010
13.597
14.152
14.682
15.188
Average (minutes)
2.562
3.934
5.252
6.445
7.525
8.507
9.408
10.236
11.004
11.717
12.385
13.009
13.598
14.153
14.680
15.190
SD
0.0005
0.0009
0.0009
0.0008
0.0007
0.0012
0.0007
0.0012
0.0012
0.0011
0.0005
0.0012
0.0011
0.0012
0.0013
0.0010
RSD %
0.02%
0.02%
0.02%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.00%
0.01%
0.01%
0.01%
0.01%
0.01%
Table 3. Variation in peak area as effect of module swap. All variations are in the range of few % changing either the inlet or the FID detector
Original instrument configuration SSL s/n 712100036 and FID s/n 712300088
nC10
nC12
nC14
nC16
nC18
nC20
nC22
nC24
nC26
nC28
nC30
nC32
nC34
nC36
nC38
nC40
2620726
2666702
2615432
2636561
2573604
2588848
2574011
2569231
2549064
2564570
2637520
2631510
2559913
2593130
2492829
2552320
SD
12355
10941
11571
11889
12894
12092
15913
14767
15078
15223
14298
13319
11161
13430
12358
13908
RSD %
0.47%
0.41%
0.44%
0.45%
0.50%
0.47%
0.62%
0.57%
0.59%
0.59%
0.54%
0.51%
0.44%
0.52%
0.50%
0.54%
2604178
Average (counts)
Change of SSL module - Instrument configuration SSL 712300021 / FID 712300088
Average (counts)
2705439
2722254
2654680
2680682
2615418
2647035
2626550
2624551
2604909
2618663
2699958
2707570
2658013
2713142
2598635
SD
8276
7559
8759
9119
11059
11146
12635
14822
13711
16916
16529
17096
12977
10030
12448
10215
RSD %
0.31%
0.28%
0.33%
0.34%
0.42%
0.42%
0.48%
0.56%
0.53%
0.65%
0.61%
0.63%
0.49%
0.37%
0.48%
0.39%
Variation %
-3.2%
-2.1%
-1.5%
-1.7%
-1.6%
-2.2%
-2.0%
-2.2%
-2.2%
-2.1%
-2.4%
-2.9%
-3.8%
-4.6%
-4.2%
-2.0%
2666225
Change of FID module - Instrument configuration SSL 712300021 / FID 712300126
Average (counts)
2752208
2777431
2705697
2728377
2668020
2699389
2678126
2670723
2649792
2665081
2745907
2757795
2703327
2763143
2653118
SD
13455
15147
15120
11600
15162
14201
15885
15954
14781
15601
11514
14864
10635
13223
15755
11218
RSD %
0.49%
0.55%
0.56%
0.43%
0.57%
0.53%
0.59%
0.60%
0.56%
0.59%
0.42%
0.54%
0.39%
0.48%
0.59%
0.42%
Variation %
-1.7%
-2.0%
-1.9%
-1.8%
-2.0%
-2.0%
-2.0%
-1.8%
-1.7%
-1.8%
-1.7%
-1.9%
-1.7%
-1.8%
-2.1%
-2.4%
Table 4. Variation in retention time as effect of module swap. All variations are in the range of 1/100 of a minute or less, changing either the inlet or the FID detector
Original instrument configuration SSL s/n 712100036 and FID s/n 712300088
nC10
nC12
nC14
nC16
nC18
nC20
nC22
nC24
nC26
nC28
nC30
nC32
nC34
nC36
nC38
nC40
Average (minutes)
2.562
3.934
5.252
6.445
7.525
8.507
9.408
10.236
11.004
11.717
12.385
13.009
13.598
14.153
14.680
15.190
SD
0.0005
0.0009
0.0009
0.0008
0.0007
0.0012
0.0007
0.0012
0.0012
0.0011
0.0005
0.0012
0.0011
0.0012
0.0013
0.0010
RSD %
0.02%
0.02%
0.02%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.00%
0.01%
0.01%
0.01%
0.01%
0.01%
Change of SSL module - Instrument configuration SSL 712300021 / FID 712300088
Average (minutes)
2.566
3.938
5.255
6.448
7.527
8.509
9.410
10.238
11.005
11.719
12.386
13.011
13.599
14.154
14.679
15.188
SD
0.0006
0.0012
0.0007
0.0004
0.0009
0.0007
0.0007
0.0014
0.0007
0.0015
0.0009
0.0015
0.0009
0.0014
0.0015
0.0014
RSD %
0.02%
0.03%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
Variation %
-0.2%
-0.1%
-0.1%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Change of FID module - Instrument configuration SSL 712300021 / FID 712300126
Average (minutes)
2.563
3.935
5.254
6.446
7.525
8.508
9.408
10.237
11.004
11.718
12.384
13.011
13.598
14.154
14.679
15.186
SD
0.0007
0.0007
0.0010
0.0007
0.0014
0.0008
0.0009
0.0014
0.0010
0.0009
0.0009
0.0010
0.0018
0.0007
0.0014
0.0019
RSD %
0.03%
0.02%
0.02%
0.01%
0.02%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.01%
0.1%
0.1%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Variation %
6
Injector module endurance test
Module robustness was tested mechanically by
having ten different operators repeatedly insert
and remove the module. The operators had
widely varied skills and knowledge, with some
subjects having no prior GC experience. Two
operators were from the shipping department,
and two worked in order processing. Two had
limited GC knowledge and were the Quality
Manager and Product Manager of a different
product line. Finally, two engineers and two GC
scientists that also presided over all of the tests
participated. The module subjected to the test
was the “Instant Connect” SSL injector (S/N:
712300021), and the sequence applied by each
operator included powering off the GC,
removing the module, inserting the module, and
powering up the GC until it reached stand-by
condition. The total average test sequence time
was six minutes. Each operator repeated this
cycle ten times.
7
After each operator finished his or her cycle, the
column was connected again to the SSL injector
and FID detector, followed by a double blank
run. Ten automated injections of the
hydrocarbon mix completed the test. Tables 5
and 6 include the results of the last two runs
performed before starting the ruggedness test
and the two initial runs of the new sequence. It
is useful to note that the new sequence was
started the day after the last sequence of
injections was recorded. The variations of both
absolute peak areas and retention times indicate
the module performed perfectly without
requiring any maintenance.
Table 5. Variation in peak area before and after 100 times module replacement cycle
nC10
nC12
nC14
nC16
nC18
nC20
nC22
nC24
nC26
nC28
nC30
nC32
nC34
nC36
nC38
nC40
Injection 9 before
IC swap
2754987
2779540
2709468
2720590
2662466
2694642
2671418
2666034
2640542
2660383
2748956
2756412
2705301
2768808
2658421
2670870
Injection 10 before
IC swap
2751265
2775027
2708032
2732281
2677453
2705799
2688053
2684329
2667261
2684684
2755387
2771243
2709754
2772642
2651536
2665536
Injection 1 after
IC swap
2767372
2791927
2719553
2738439
2664499
2693367
2672357
2657758
2643338
2655810
2738028
2745997
2704789
2768416
2664390
2670998
Injection 2 after
IC swap
2756768
2787601
2711585
2738364
2687682
2720242
2699762
2690563
2663741
2677520
2756966
2774421
2711745
2765971
2664631
2676359
-0.59%
-0.61%
-0.43%
-0.23%
0.48%
0.46%
0.58%
0.99%
0.90%
1.08%
0.63%
0.91%
0.18%
0.15%
-0.48%
-0.20%
Variation
Table 6. Variation in retention time before and after 100 times module replacement cycle
nC10
nC12
nC14
nC16
nC18
nC20
nC22
nC24
nC26
nC28
nC30
nC32
nC34
nC36
nC38
nC40
Injection 9 before
IC swap
2.562
3.935
5.253
6.447
7.525
8.507
9.408
10.235
11.003
11.717
12.383
13.010
13.598
14.153
14.678
15.185
Injection 10 before
IC swap
2.563
3.933
5.255
6.445
7.523
8.508
9.407
10.237
11.005
11.717
12.383
13.012
13.595
14.154
14.677
15.185
Injection 1 after
IC swap
2.563
3.935
5.253
6.447
7.525
8.507
9.408
10.238
11.003
11.718
12.385
13.010
13.598
14.153
14.678
15.183
Injection 2 after
IC swap
2.563
3.935
5.253
6.447
7.523
8.508
9.407
10.237
11.003
11.718
12.385
13.012
13.600
14.155
14.680
15.187
Variation
-0.03%
-0.04%
0.04%
-0.03%
-0.02%
0.01%
-0.02%
-0.02%
0.02%
-0.01%
-0.01%
0.02%
-0.02%
0.00%
-0.01%
0.01%
Conclusion
Te ch ni cal N ote 5 2 3 6 4
The “Instant Connect” modules on the TRACE 1300
Series GC offer important advantages over conventional
GC instrumentation, such as maintaining instrument
uptime and continuing to run even when an injector or
detector must be replaced for maintenance purposes.
Additional advantages include the ability to upgrade from
a single-channel GC to a double-channel GC to increase
instrument productivity and the option to add a new
detector module to respond to new application requirements.
The design of “Instant Connect” modules as self-independent
components of the GC, which incorporate all mechanical
and electronic components with calibration information,
permits the user to rapidly remove and install new modules
without any service assistance. The modularity of the
design provides configuration flexibility never before
available in a GC and also maintains the highest
reproducibility and ruggedness standards. The test results
show that module internal calibration allows module-tomodule reproducibility to be within 5% of the variances
in absolute peak area and retention times. The compact
size and robustness of the module design enable the
modules to be repeatedly replaced without impacting
instrument performance.
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