Helium to Hydrogen Conversion for GC/MS and GC/MS/MS Analysis of Semi-Volatile, Volatile, and PAH Compounds: A Practical Guide for Environmental Laboratories

Optimizing Laboratory Operations
Poster Presentation

Presented by A. Willey
Prepared by A. Andrianova, E. Fausett, B. Quimby, S. Haddad, A. Smith Henry, D. Walker
Agilent Technologies, 2850 Centerville Rd., Wilmington, DE, 19808, United States


Contact Information: [email protected]; 302-636-3969

ABSTRACT

In response to the problems laboratories have had with helium shortages, tools and processes are available for predictable transition of GC/MS analysis to hydrogen carrier gas. For GC/MS hydrogen is the best alternative to helium. However, there are several important factors that must be considered to achieve success.
This presentation provides an overview of several successful hydrogen implementations, including pesticides, volatile organics (VOAs), semivolatiles (SVOCs), and polycyclic aromatic hydrocarbons (PAHs).
Transitioning from helium to hydrogen entails an assessment of hardware and method components, including injection technique, column dimensions, column phase ratio, and MS EI source selection. Method translation techniques, coupled with retention time locking, ensure the same elution order and retention times as with helium carrier gas.
The HydroInert EI source optimized for use with hydrogen carrier gas addresses the problem with in-source reactions that some compounds exhibit. Excellent library match scores, peak shape, and sensitivity approaching that with helium are attainable when following the recommendations outlined in this presentation.
Some compounds pose a greater challenge when transitioning the GC/MS analysis from helium to hydrogen carrier gas. Compounds prone to reaction with hydrogen can be particularly difficult. This presentation will highlight the following successful implementations of hydrogen carrier gas:
• VOAs analyzed by headspace-GC/MS enabling accurate quantitation over 0.05 to 25 ppb. The MDLs were at sub-ppb level, and an average library match score against NIST 2020 was 94
• SVOCs met the desired linearity requirements over a wide calibration range (0.1 to 100 ppm)
• PAHs in soil. The translated method with hydrogen outperforms the results with helium in terms of peak shape, linearity over 0.1 to 1,000 ppb, internal standard stability, and detection limits as low as 0.09 ppb with GC/MS/MS.
The identified guidelines resulted in successful transition of multiple GC/MS methods to hydrogen carrier gas across a variety of applications.