QuEChERS-液相色谱-串联质谱法测定棕榈原油中敌草快等6种农药残留

建立了QuEChERS-液相色谱-串联质谱同时测定棕榈原油中敌草快、乐果、倍硫磷、倍硫磷亚砜、倍硫磷砜、氟吡甲禾灵残留量的方法。以回收率及基质效应为考察指标,评估了乙二胺-N-丙基硅烷(PSA)/C18混合物、C18键合锆胶(Z-Sep+)/C18混合物、Z-Sep+、C18 4种分散吸附剂的净化效果,结果表明Z-Sep+/C18的净化效果最佳。样品采用含1%(v/v)乙酸的甲醇溶液提取,Z-Sep+/C18分散固相萃取净化;液相色谱以Atlantis T3色谱柱梯度洗脱分离,质谱分析采用电喷雾正离子电离、多反应监测模式,以基质匹配校准曲线外标法进行定量。6种农药在3个添加水平(10、20、250 μg/kg)下的回收率范围为70.0%~97.9%,相对标准偏差范围为2.6%~10.2%; 6种农药的定量限(S/N≥10)为0.1~2.5 μg/kg。该方法简便、灵敏、准确、环保,适用于棕榈原油中上述6种农药残留的定性、定量分析。

Determination of six pesticide residues including diquat in crude palm oil by QuEChERS-liquid chromatography- tandem mass spectrometry

A fast method based on QuEChERS methodology was developed for the simultaneous determination of diquat, dimethoate, fenthion, fenthion-sulfoxide, fenthion-sulfone, haloxyfop-methyl in crude palm oil using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The clean-up effects of four dispersive sorbents were evaluated in terms of recoveries and matrix effects. The four sorbents were the mixture of primary secondary amine (PSA) and C18, a mixture of two sorbents a bonded C18 zirconia-coated silica (Z-Sep+) and C18, Z-Sep+, C18. As a result, the best effects were obtained from using the mixture of Z-Sep+ and C18 sorbents. The samples were extracted with methanol containing 1%(v/v) acetic acid. The extracts were cleaned up with dispersive solid phase extraction using Z-Sep+/C18 sorbents. Chromatographic analysis was carried out on an Atlantis T3 column with gradient elution. The pesticides were analyzed by positive electrospray ionization-tandem mass spectrometry under multiple reaction monitoring mode. The quantification was achieved using matrix-matched standard calibrations as external standard. The recoveries at the fortification levels of 10, 20 and 250 μg/kg in crude palm oil ranged from 70.0% to 97.9% with the relative standard deviations of 2.6%-10.2%. The limits of quantification (S/N≥10) were 0.1-2.5 μg/kg. The method has been proven to be simple, sensitive, accurate and environmental and thus suitable for the determination of the six pesticide residues above in crude palm oil.