Hydrogen vs. Helium as carrier gases in GC-MS/MS for pesticide residue analysis: a comparative evaluation

This study presents a comprehensive comparison between helium and hydrogen as carrier gases in gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) for multiresidue pesticide analysis. Using a shared instrumental platform, method parameters were carefully adapted for each carrier gas to maintain equivalent chromatographic efficiency, including adjustments to column dimensions, flow rates, and oven temperature programs. Method performance was evaluated in terms of chromatographic resolution, sensitivity, matrix effects, and regulatory reliability across tomato, pepper, and zucchini matrices. Hydrogen demonstrated faster analysis times and improved resolution in several cases, particularly in separating matrix interferences. However, helium consistently offered higher sensitivity, especially at lower concentrations. At 2 µg/kg, helium enabled the identification of over 90 % of compounds in most matrices, while hydrogen remained below 55 %. Matrix effect evaluations showed slightly better results with helium, though both gases provided acceptable performance, with most compounds falling within the negligible effect range. A proficiency test sample further validated the method, confirming that both gases produced results within acceptable z-score limits. Overall, hydrogen proved to be a viable and sustainable alternative for routine applications, though helium remains preferable when ultra-trace sensitivity or method robustness under stricter regulatory conditions is required.