Strategies to Contend with Helium Supply Shortages Including a Survey of Semi-volatile Analyses (EPA 8270E) with Helium, Hydrogen and Nitrogen Carrier Gasses by GC/MS and GC/MS/MS.Operational Issues Impacting the Environmental Laboratory Industry
Poster Presentation
Prepared by E. Fausett1, A. Andrianova2, B. Quimby2
1 - Agilent, 1 Victorian Lane, Landenberg, Pa, 19350, United States
2 - Agilent, , , United States
Contact Information: [email protected]; 435-830-2901
ABSTRACT
Helium supply shortages have been a recurring problem for analytical laboratories. Price fluctuations and supply deficiencies cause disruptions for chromatographers using helium as a carrier gas.
Many laboratories are experiencing an existential need to reduce or even eliminate the consumption of helium to contend with this situation.
Fortunately, helium consumption can be significantly reduced through adjusting method parameters, utilizing a programmable helium conservation module, and inspecting and maintaining helium infrastructure for leak prevention.
If an alternative to helium is necessary, hydrogen is the best alternative for GC/MS. Hydrogen is not an inert gas and usage can introduce complications for some analytes such as chemical reactions in the GC/MS source. This can result in peak tailing and reduced spectral fidelity. The HydroInert EI source has been demonstrated to significantly reduce these negative effects.
Another alternative carrier gas is nitrogen. Nitrogen does not introduce chemical reactions as can occur with hydrogen but offers its own challenges. Sensitivity is reduced while inlet and column parameters must be carefully optimized to maintain resolution. Despite these disadvantages, nitrogen offers a useful third alternative.
To contrast the performance of these carrier gasses a panel semi-volatiles compounds was analyzed and evaluated using helium, hydrogen and nitrogen.
The following results are observed:
• Excellent spectral fidelity can be achieved with all three carrier gasses. Ion ratio challenges typically observed with hydrogen carrier gas are significantly reduced with the HydroInert source.
• Excellent chromatographic peak shapes, including for the late-eluting PAHs, can be obtained with all three carrier gases with the appropriate optimization of inlet parameters and source hardware.
• Calibration performance is best with helium carrier gas. Hydrogen and nitrogen offer a reasonable second and third choice, respectively.
• Instrument sensitivity is also best with helium carrier gas closely followed by hydrogen. Nitrogen offers a reasonable alternative but requires more extensive optimization.
