低温冷冻及分散固相萃取净化-超高效液相色谱-串联质谱法测定植物油中104种农药残留

Low temperature freezing followed by dispersive solid phase extraction for the determination of 104 pesticide residues in vegetable oils using ultra-performance liquid chromatography-tandem mass spectrometry

建立了适用于植物油中104种农药残留的检测方法。通过液液萃取（LLE）提取目标化合物,再借助离心、冷冻和分散固相萃取（D-SPE）净化手段,依托超高效液相色谱-串联质谱测定。以回收率和共提取物为衡量指标,着重优化了6种提取方式、不同冷冻时间及PSA（primary secondary amine）、GCB（graphite carbon black）和C18这3种不同固相萃取填料不同组合的效果。在0.01、0.02和0.05 mg/kg水平的平均添加回收率为55%~121%,RSD为0.47%~19.2%,80%的目标物的定量限可达到1μg/kg,低于我国相关标准限量,能够满足多种农药残留同时分析的要求。该方法步骤简便、可靠、稳定,可应用于进口植物油中多种农药残留的快速检测与确证的日常检测工作中,具有一定的推广价值。

A method using liquid-liquid extraction（LLE）followed by clean-up steps of centrifugation,freezing and dispersive solid phase extraction（D-SPE）and ultra-performance liquid chromatography（UPLC）coupled with tandem mass spectrometry（MS / MS）has been developed for the determination of trace levels of 104 pesticides in vegetable oils. LLE has been optimized to extract these pesticide residues from oils to obtain the highest recoveries of pesticides and the lowest co-extract fat residue in the final extract. In addition,the centrifugation and freezing steps as well as D-SPE with primary secondary amine（PSA）,graphite carbon black（GCB）and C18 were used as the clean-up steps to minimize the co-extract fat. The recoveries obtained ranged from 55% to 121% and the relative standard deviations（RSDs）ranged from 0. 47% to 19. 2% at the spiked levels of 0. 01,0. 02 and 0. 05 mg / kg. This method,combining with accurate and sensitive detection,allowed quantification and confirmation at levels as low as 1 μg / kg for 80% of the analytes. The limits of quantification（LOQs）of the most compounds were below the maximum residue limits（MRLs）established by the Chinese legislations for oils. The proposed method was applied successfully for the residue determination of the selected pesticides in oils.