Determination of 50 pesticide residues in fruits by gas chromatography-tandem mass spectrometry

A method for the determination of 50 pesticides in fruits by gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The three QuEChERS methods (the original one without buffer, the one with acetate buffer and the one with citrate buffer) were compared. The purification effects of primary secondary amine (PSA) and SinChERS-Nano column were also investigated. The results showed that the acetate buffer and the citrate buffer had positive influence on the extraction compared to the original method without buffer, and there was no significant difference between the two methods using buffers. Finally, the QuEChERS method using acetate buffer was chosen as the extraction method. By comparing the purification effect images and the total ion current (TIC) chromatograms, SinChERS-Nano column was revealed to have a better cleaning effect, and was chosen for cleanup. The recoveries of methamidophos, acephate, omethoate, chlorothalonil and dicofol were in ranged of 71. 2%-129. 2%, the other 45 pesticides were ranged from 79. 1% to 122. 3%. The limits of detection (LODs) were 0. 3-3. 0 mu g/kg and the limits of quantification (LOQs ) were 1. 0-10. 0 mu g/kg. The method is rapid and suitable for the screening of the 50 pesticide residues in citrus, grapes and other fruit samples.