Comparison of nitrogen and helium as carrier gases for determination of pesticide residues in foods via gas chromatography–tandem mass spectrometry with atmospheric pressure chemical ionization

Abstract

The applicability of nitrogen as an alternative carrier gas to helium for the multiresidue analysis of pesticides using gas chromatography–tandem mass spectrometry with atmospheric pressure chemical ionization (GC–(APCI)MS/MS) was examined. The methods using both carrier gases were validated for 151 pesticides in foods at a spiking level of 0.01 ppm, maintaining identical conditions for both gases, including the GC column and carrier gas flow rate. The use of nitrogen resulted in slightly broader peaks and lower peak intensities that those observed upon using helium. However, sufficient sensitivity was achieved for all target compounds because of the high sensitivity of the GC–(APCI)MS/MS method. Further, target-compound separation was not significantly affected by the carrier gas type, and no interfering peaks were observed, demonstrating the high selectivity of the nitrogen-based method, even beyond the optimum linear velocity. Finally, the analytical performance of the nitrogen-based method was comparable to those of the helium-based method. Considering cost-effectiveness of nitrogen, this method is highly valuable in the event of helium shortages and for routine pesticide residue monitoring.