Determination of fungicide anilinopyrimidine residues in food by series solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was established for the determination of fungicide anilinopyrimidine residues including pyrimethanil, mepanipyrim, and cyprodinil in foodstuffs with series solid phase extraction (SPE). The food sample was first extracted with ethyl acetate, and then purified by an ENVI-Carb cartridge and a Florisil SPE cartridge. The analytes were determined by HPLC-MS/MS and quantified by external standard method. The mass spectrometric detection was operated with electrospray in positive ionization mode and the fungicide anilinopyrimidines were identified in multiple reaction monitoring (MRM) mode. The linear range of the method was 1 - 20 microg/L, with the correlation coefficient (r2) over 0. 999 0. The transitions of the precursor ions to two selected product ions were involved, in which one group for quantification were m/z 200. 1/107. 1 for pyrimethanil, m/z 224. 0/106. 0 for mepanipyrim and m/z 226. 0/108. 1 for cyprodinil, and the other group for identification were m/z 200. 1/183. 1 for pyrimethanil, m/z 224. 0/131. 1 for mepanipyrim and m/z 226. 0/133. 1 for cyprodinil, respectively. No significant matrix effect was found for spiked samples after the purification. The recoveries of the fungicide anilinopyrimidines spiked in food samples were 73.2% -98.7% at the spiked levels of 0. 1, 0.5, 1.0 microg/kg. The relative standard deviations (RSDs) were less than 10%. The limits of detection (LODs) and limits of quantification (LOQs) were 0. 03 microg/kg and 0.1 microg/kg for the three fungicides, respectively. The results showed that the proposed method is sensitive and accurate for the determination of fungicide anilinopyrimidines in foodstuffs. The method should be applicable for routine analysis of pyrimethanil, mepanipyrim, cyprodinil residues in foodstuffs.