Gas chromatography-high-resolution time-of-flight mass spectrometry in pesticide residue analysis: advantages and limitations

In this study, 20 modern pesticides representing various chemical classes with a broad range of physico-chemical properties were selected for demonstration of applicability of exact mass orthogonal acceleration time-of-flight (TOF) mass spectrometer GCT (Micromass, UK) in GC analysis of their residues in purified peach extracts. The influence of experimental chromatographic conditions as well as various detector settings and data processing strategies on the performance characteristics of analytical procedure achieved during optimisation process were critically discussed. As documented in this study unbiased identification and reliable quantification of target analytes is possible due to: (i) application of narrow mass window (0.02-0.05 Da) for extracting analytical ions; (ii) availability of full spectral information even at very low levels of target analytes. With only a few exceptions, the limits of quantification for most of the pesticides involved in this study were fair below 0.01 mg/kg level, which represents the maximum EU residue limit set recently for pesticide residues in cereal-based foods and baby foods for infants and young children.