Determination of 255 pesticides in edible vegetable oils using QuEChERS method and gas chromatography tandem mass spectrometry

In this study, a simple and high-throughput method for determination of 255 pesticides in vegetable oils was developed based on QuEChERS sample preparation method combined with gas chromatography-triple quadrupole mass spectrometry. Different clean-up approaches were tested: A, 150 mg PSA + 150 mg C18; B, 250 mg PSA + 250 mg C18; C, 250 mg PSA + 250 mg C18 + 15 mg GCB; D, 250 mg PSA + 250 mg C18 + 50 mg GCB; and E, EMR-Lipid(TM). Best clean-up capacity was observed for EMR clean-up. The extraction procedures and parameters, including extraction time, solvent/sample ratio, and buffer system, were also thoroughly investigated and optimized. The limits of quantification (LOQ) ranged between 5 and 50 mu g kg(-1), and for the majority of the pesticides the LOQs were 5 mu g kg(-1), which were below the regulatory MRLs. Most recoveries at seven spiking levels were in the range of 70-120 % with RSDs < 20 % indicating satisfactory accuracy. The coefficient of determination (r (2)) was > 0.99 within the calibration linearity range of 2-500 mu g L-1 for the majority of the pesticides. This method was proved to be simple, sensitive, and effective, which can be applied for large-scale pesticide screening and quantification in vegetable oils.