Determination of 28 pesticide residues in sunflower seeds by gas chromatography-tandem mass spectrometry

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for the determination of 28 pesticide (including fludioxonil, cypermethrin, metolachlor and etc.) residues in sunflower seeds. The samples were extracted with acetonitrile, purified with gel permeation chromatography (GPC) and solid-phase extraction (SPE). The analysis of the extracts was performed using tandem mass spectrometry under multiple reaction monitoring (MRM) mode. Matrix-matched calibration curve was used to qualify the residue concentrations with external standard method. The results showed that GPC and SPE purification could eliminate the interference constituents. Good linearity was obtained in the range of 0.01-0.5 mg/L for 28 pesticides with coefficients of determination greater than 0.994. The mean recoveries mostly ranged between 74% and 120% at the three spiked concentration levels (50, 100, 200 μg/kg), and the relative standard deviations were between 0.9% and 9.5% (n=5), the limits of quantification(LOQ) were in the range of 0.2-7.6 μg/kg. The method presented was sensitive, accurate and reliable. Therefore, it could meet the needs for the determination of pesticide residues, and could be used for monitoring the level of residues in the process of sunflower seeds production.