Abstract:

A stomach large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) coupled with mini solid phase extraction (SPE) method for the rapid and simultaneous determination of 13 organic phosphorous pesticide residues in spinach samples is presented. The compounds were identified with their retention times and the abundance ratios of qualifier and target ions. Quantification was calculated based on the extraction of spiking standards in a blank sample. The limit of detection (LOD) was determined by the experimental value of the signal-to-noise ratio of 3∶1, and the limit of quantification (LOQ) was defined at the experimental value of the signal-to-noise ratio of 10∶1. The recoveries obtained ranged from 76.8% to 114.0% with the relative standard deviations between 1.5% and 17.6% except dimethoate. The LODs ranged from 0.5 to 25 μg/kg. This simple, rapid and reliable method has wide applications for the simultaneous determination of multiple pesticide residues in spinach and possibly other species.

Key words: gas chromatography-mass spectrometry （GC-MS）, organic phosphorous pesticide, spinach , stomach large volume injection （LVI）, solid phase extraction （SPE）