Analysis of Eight Organophosphorus Pesticide Residues in Fresh Vegetables Retailed in Agricultural Product Markets of Nanjing, China

A method to effectively remove pigments in fresh vegetables using activated carbon followed cleanup through solid phase extraction (SPE) cartridge to further reduce matrix interference and contamination, was established to determine eight organophosphorous pesticides (OPPs) by gas chromatography (GC) with nitrogen–phosphorus detection (NPD) in this study, and it has been successfully applied for the determination of eight OPPs in various fresh vegetables with the recoveries ranging from 61.8% to 107%. To evaluate eight OPPs residue level, some fresh vegetables retailed at three agricultural product markets (APM) of Nanjing in China were detected, the results showed that phorate in Shanghai green (0.0257 μg g−1) and Chinese cabbage (0.0398 μg g−1), dimethoate in Shanghai green (0.0466–0.0810 μg g−1), Chinese cabbage (0.077 μg g−1), and spinach (0.118–0.124 μg g−1), methyl-parathion in Shanghai green (0.0903 μg g−1), Chinese cabbage (0.157 μg g−1), and spinach (0.0924 μg g−1), malathion in Shanghai green (0.0342–0.0526 μg g−1), chorpyrifos in spinach (0.106–0.204 μg g−1), and Chinese cabbage (0.149 μg g−1), chlorfenvinfos in carrot (0.094–0.131 μg g−1), were found. However, fonofos and fenthion were not detected in all the collected vegetable samples.