Determination of 126 pesticides residues in soybean oil by solid phase extraction-gas chromatography-tandem mass spectrometry

A multi-residue analysis method was established for simultaneous determination of 126 pesticides in soybean oil using SPE-gas chromatography-tandem mass spectrometry (GC/MS/MS). The samples were degreased by n-hexane saturated with acetonitrile and extracted by n-hexane saturated acetonitrile under mechanical shaking. Then the extracts were centrifuged at −5 ℃ and 20000 r/min for 5 min, and cleaned-up with Captiva EMR-Lipid solid phase extraction column. After being re-dissolved with ethyl acetate, the samples were detected using multiple reaction monitoring (MRM) on GC-MS/MS system and quantified with external standard method using matrix matched calibration curves. The results showed that: in the range of 0.003-0.2 mg/L, good linear relationship were obtained between the concentrations of 126 pesticides and their corresponding peak areas, and the R² was greater than 0.995. The recoveries of 126 pesticides ranged from 60% to 119% at the spiked levels of 0.005, 0.01 and 0.05 mg/kg. The RSDs were lower than 20% for 122 pesticides, and were lower than 25% for the other four pesticides. The method can effectively remove glycerolipid and some lipophilic interference from the soybean oil. The sensitivity, accuracy and precision of the method meet the requirements of pesticide residue detection. It provides an efficient and reliable analytical method for monitoring the level of pesticide residues in soybean oil and effectively preventing the health risks.