Hydrogen Carrier Gas for Analyzing Pesticides in Pigmented Foods with GC/MS

Abstract This application note describes the key strategies for pesticide analysis with gas chromatography/triple quadrupole mass spectrometry (GC/TQ) using hydrogen as the carrier gas while maintaining sensitivity to meet maximum residue limits (MRLs). The key aspects addressed in this work include the recommended column configuration, the optimized injection conditions, and the appropriate choice of the mass spectrometer (MS) electron ionization (EI) source hardware developed for use with hydrogen carrier gas. The 20 m × 20 m (0.18 mm × 0.18 μm) Agilent HP-5ms UI midcolumn backflush configuration allowed for maintaining the same retention times as with helium, leading to time savings associated with method translation. The resulting chromatographic resolution achieved under the optimal conditions with hydrogen surpassed that with helium. The optimized injection conditions included solvent vent mode, a 2 mm dimpled liner, and the use of analyte protectants. The analyte response with hydrogen was enhanced on average 10-fold when using the optimized conditions compared to using hydrogen carrier gas with the injection conditions, commonly used with helium. Both the Agilent HydroInert and the Agilent High Efficiency Source (HES) resulted in nearly identical spectra bserved with hydrogen and helium, which allowed using the same multiple reaction monitoring (MRM) transitions and collision energies as with helium. The ability to use the same MRMs, collision energies, and retention times greatly simplified the transition from helium to hydrogen.