Application of multi-residue analytical method for determination of 496 pesticides in frozen gyoza dumplings by GC-MS and LC-MS

摘要

The applicability of multi-residue analytical method for 496 pesticides (including metabolites) in frozen gyoza dumplings was verified. This method involved extraction using aqueous acetonitrile (around 70% of acetonitrile content) followed by cleanup using octadecylsilyl (ODS) and primary secondary amine (PSA) mini-column solid-phase extraction (SPE). The target compounds were determined by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). Validation tests were performed on frozen gyoza dumplings fortified at 0.01 and 0.10 μg/g in accordance with the guideline issued by the Japanese Ministry of Health, Labour and Welfare. Among the 496 pesticides tested, 378 pesticides were found to conform to the guideline when the solvent standard was used, and 432 pesticides conformed when the matrix-matched standard was used, respectively. The limits of quantitation (S/N≥10) were set at 0.01 μg/g for all, except 20 of the pesticides that were tested. Although no significant matrix effects were observed for most of the pesticides, the use of the matrix-matched standard was preferable to the solvent standard for accurate quantitation. The method was applied to 11 commercial samples, and 14 different pesticides were detected from 8 samples at concentrations ranging from trace levels (<0.01 μg/g) to 0.11 μg/g.