关键词: 小宗作物, 液相色谱-串联质谱, 农药残留, 分散固相萃取

Abstract: A simple analytical method was established using dispersive solid phase extraction combined with liquid chromatography-positive mode electrospray ionization-tandem mass spectrometric (LC-MS/MS) for the determination of six pesticide residues in ginger, sweet potato, potato, and litchi, including carbendazim, imidacloprid, aldicarb, triadimefon, acetochlor and difenoconazole. The analytes were extracted with acetonitrile and cleaned up using primary secondary amine (PSA) and octadecyl silane (C18). Qualitative analysis of six analytes was carried out under the positive scanning model after the chromatographic separation on a reversed phase C18 column with gradient elution using a mobile phase composed of methanol and 0.1% formic acid aqueous solution. A good linearity was observed for the six pesticides in the range of 10–500 μg/L with a coefficient of determination (r) of greater than 0.995. The recoveries of the pesticides in four classical minor crops were in the range of 87.9%–110.3% at three spiked concentration levels, and the precision, as indicated by relative standard deviations (RSDs, n=5), was not more than 14.6%. The method is simple, rapid and sensitive, and can meet the requirements for the determination of pesticide residues in minor crops.

Key words: minor crops, liquid chromatography-tandem mass spectrometry (LC-MS/MS), pesticide residues, dispersive solid phase extraction