[Determination of nine pesticide residues in vegetables by matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry].

A matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry (MSPD-UPLC-MS/MS) method was established for the simultaneous deter- mination of carbendiazin, omethoate, carbofuran, aldicarb, chlorpyrifos, methamidophos, phorate, parathion and parathion-methyl residues in vegetables. The samples were extracted by acetonitrile and separated with salting out method. And then the supernatants were purified by matrix solid-phase dispersion for the UPLC-MS/MS analysis. The separation was performed on a Waters Acquity UPLC system with a BEH C18 column with the gradient elution of acetonitrile and water containing 0. 1% (v/v) acetic acid. The nine pesticides were determined in the modes of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). The ana- lytes were quantified by matrix matched standard solution curves. The limits of detection (S/N ≥ 3) were 0.8-4.0 µg/kg. The average recoveries were 72.8%-117.4%. The detection rates were 42.0% for chlorpyrifos, 14.0% for carbendiazin and 1.5% for dimethoate, and the exces- sive rate of chlorpyrifos was 8.0% in the determination of 50 real samples; the other pesticides were not detected. The method is simple, accurate and highly reproducible. This method is suit- able for the quality control of pesticide residues in risk monitoring of the safety of the foods.