Abstract:

A matrix solid-phase dispersion-ultra performance liquid chromatography-tandem mass spectrometry (MSPD-UPLC-MS/MS) method was established for the simultaneous determination 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 analytes 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 excessive 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 suitable for the quality control of pesticide residues in risk monitoring of the safety of the foods.

Key words: matrix solid-phase dispersion (MSPD), pesticide residues, risk monitoring, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), vegetables