Spotlight on the Gulf Coast Conference - Analytical Instrumentation
Table 2. Results for skewness, resolution and retention time repeatability (precision %RSD) from the narrow and wide bore columns
Narrow bore
n-Paraffi n C5
C6 C7 C8 C9
C10 C11 C12 C14 C15 C16 C17 C18 C20 C24 C28 C32 C36 C40 C44
Skewness Resolution RT Prec (n=8)
1.025 1.009 1.020 0.998 0.990 0.984 0.986 0.987 0.981 0.971 0.970 0.969 0.968 0.958 0.951 0.956 0.927 0.929 0.909 0.893
n/a 4.7
19.6 29.1 20.2 15.5 13.2 12.0 21.9 10.3 10.0 10.0 10.0 19.6 35.9 30.4 26.0 24.6 21.3 21.6
0.056 0.061 0.060 0.063 0.065 0.064 0.061 0.058 0.052 0.049 0.049 0.053 0.068 0.069 0.063 0.059 0.052 0.044 0.024 0.023
1.004 1.008 1.001 0.862 0.984 0.980 0.993 0.972 0.988 0.991 0.995 0.983 0.989 0.961 0.981 0.979 0.999 0.992 1.007
Wide Bore
Skewness Resolution RT Prec 1.010
n/a 3.0 5.5 8.0
11.9 8.1 8.0 6.9
11.9 5.2 4.6 4.4 4.3 8.0
13.7 11.3 9.5 7.9 6.7 5.8
Table 3. Results of RGO #2 from both columns. Temperatures are listed in Celsius RGO #2 % off
IBP 10 20 30 40 50 60 70 80 90 95
FBP
BP Temp 106.111 195.556 233.333 266.667 297.778 321.111 341.667 358.333 377.778 406.111 431.111 496.111
Certifi cate of Analysis
Valid Window 7.000 4.444 5.000 4.778 4.278 4.278 4.278 4.278 4.278 4.278 5.000
11.778
Actual Temp 104.640 195.390 233.930 267.390 297.890 322.100 343.060 359.270 378.530 407.140 432.420 499.740
Narrow Bore column results Variance
-1.471 -0.166 0.597 0.723 0.112 0.989 1.393 0.937 0.752 1.029 1.309 3.629
Actual Temp 104.326 194.853 233.104 265.903 295.029 320.457 341.600 357.853 377.186 406.136 431.519 501.809
Wide Bore Column Results Variance
-1.785 -0.703 -0.229 -0.764 -2.749 -0.654 -0.067 -0.480 -0.592 0.025 0.408 5.698
0.084 0.083 0.079 0.081 0.084 0.086 0.074 0.068 0.068 0.056 0.064 0.066 0.066 0.074 0.073 0.073 0.078 0.052 0.073 0.085
Figure 2 represents a chromatogram from RGO #2 on the narrow bore column. This chromatogram is presented without baseline subtraction to demonstrate raw data on this thin fi lm column.
Table 3 demonstrates excellent performance for boiling point accuracy using the RGO #2 for both columns with all boiling points passing criteria. The narrow bore column did out perform on initial boiling point (IBP) and fi nal boiling point (FBP). Five injections of the RGO #2 was performed over a three-day period using the same retention time calibration fi le with very similar results to those listed in Table 2. One example is provided.
Table 4 tabulates the results from two Canadian cross check samples analysed in this research. The average temperature and the standard deviation from the profi ciency data are presented.
The temperatures from the PerkinElmer Clarus 690 GC using the narrow bore column are documented. The % deviation from the average temperature from the CC samples compared to the temperatures from the narrow bore column are
recorded. The temperature is in degrees Celsius. Profi ciency (CC) Report Sample D282 % OFF
IBP 5
10 20 30 40 50 60 70 80 90 95
FBP
% OFF IBP
5
10 20 30 40 50 60 70 80 90 95
FBP
CC Avg Temp (n=14)
110.44 177.83 200.54 229.61 252.44 271.13 288.90 305.02 322.93 344.83 364.06 385.19 437.22
CC Avg Temp (n=13) 97.78
140.18 154.03 171.05 183.35 196.65 209.68 220.05 234.42 247.01 261.07 270.37 287.40
Future work
Additional work has been performed on enhancing analysis time on the narrow bore column. A solution with an analysis time under 5.5 minutes and an inject to inject time of under 7.5 minutes using conventional columns and a conventional GC has been achieved. This research continues with validation on these new parameters including reference standards and cross check samples. Also, Interlaboratory Study (ILS) sample results will be submitted.
Conclusion
The narrow bore column demonstrates excellent performance for skewness, retention time precision and resolution. These results outperform the requirements in ASTM D2887 with multiple injections over a period of months. The results of the three reference standards is further testament to the accuracy of this fast method.
The ability for fast cooldown and fast heating rates enhances sample throughput for the need of this industry for quick results.
Acknowledgements
The author would like to acknowledge Tom Kwoka and Leeman Bennington, Sr Field Application Specialists, and Tony Rhoden, Account Manager, PerkinElmer, and for their contribution developing a fast method for diesel range hydrocarbons which provided a starting point for this development. Also, Jay Ferraro, Scientist, PerkinElmer and Tom Grills, Envantage, in their assistance in optimizing software parameters. In addition to Miles Snow, Sr Scientist, PerkinElmer and Chris Goss, InnoTech Alberta, for their review.
References
1. ASTM Method D2887, Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography1,2,
https://www.astm.org/Standards/D2887.htm
Figure 2: Chromatogram of RGO #2 on the narrow bore column without baseline subtraction
Author Contact Details Lee Marotta, Principal Field Application Scientist, PerkinElmer • 710 Bridgeport Avenue, Shelton, CT, 06484 • Tel: 914.954.1779 • Email:
lee.marotta@
perkinelmer.com • Web:
www.perkinelmer.com
2. Using Hydrogen For Gas Chromatography,
http://www.restek. com/Landing-Pages/Content/gen_B008
CC Std Dev Narrow Bore Column Temp
3.552 1.474 1.412 1.682 2.772 2.981 3.018 3.066 3.437 3.600 3.969 4.892 4.881
2.641 2.218 2.158 3.466 2.431 0.840 2.231 1.970 2.153 1.078 1.042 0.776 1.935
110.43 176.91 200.40 229.97 253.59 271.16 289.48 304.97 323.45 345.34 363.98 384.97 438.01
Profi ciency (CC) Report Sample D283
CC Std Dev Narrow Bore Column Temp
96.91
139.99 150.64 169.18 180.89 195.95 208.04 218.62 233.26 246.72 261.09 270.29 286.79
%Dev from CC Avg -0.89 -0.13 -2.20 -1.09 -1.34 -0.36 -0.78 -0.65 -0.50 -0.12 0.01 -0.03 -0.21
%Dev from CC Avg
-0.01 -0.52 -0.07 0.16 0.46 0.01 0.20 -0.02 0.16 0.15 -0.02 -0.06 0.18
29
Table 4: Results from profi ciency (cross check) program compared to the narrow bore
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