多壁碳纳米管/N-丙基乙二胺混合吸附-超高效液相色谱-串联质谱法测定普洱茶中3种手性杀菌剂农药残留

目的建立基于手性柱/超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定普洱茶生茶和熟茶中3种手性农药(三唑酮、苯霜灵、丙环唑)对映体的分析方法。方法样品采用乙腈提取,氨基化多壁碳纳米管(aminated multi-walled carbon nanotubes,MWCNTs-NH2)和N-丙基乙二胺(primary secondary amine,PSA)混合吸附剂净化,经手性色谱柱Chiralpak-IG拆分,超高效液相-串联质谱法检测,基质外标法定量。结果 3种农药外消旋体在0.005～1.0 mg/L范围内均呈良好线性关系,定量限(limits of quantification,LOQ)为0.005～0.01 mg/kg。在3种手性农药单个对映体含量为0.1、0.01、0.0025 mg/kg加标水平下平均回收率为70.1%～110.6%,相对标准偏差(relative standard deviation,RSD)(n=6)为1.2%～13.5%。结论该方法准确、简单、灵敏,可以满足普洱茶中3种手性农药对映体残留的检测要求。

Determination of 3 chiral fungicide pesticide residues in Pu-erh tea by multi- walled carbon nanotubes/primary secondary amine mixed adsorption-ultra performance liquid chromatography-tandem mass spectrometry

Objective To establish a method for the determination of the enantiomers of 3 kinds of chiral pesticides (triadimefon, benalaxyl, propiconazole) in Pu-erh raw tea and ripe tea by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with chiral column. Methods The sample was extracted with acetonitrile, then purified with aminated multi-walled carbon nanotubes and primary secondary amine. After separated with a Chiralpak-IG chiral column, the extract was detected by UPLC-MS/MS and quantified by matrix external standard method. Results The 3 kinds of racemates of pesticides showed a good linear relationship in the range of 0.005 to 1.0 mg/L, the limit of quantification was 0.005-0.01 mg/kg. The recoveries at the single enantiomeric content of 3 spiked levels of 0.1, 0.01, 0.0025 mg/kg were in the range of 70.1%-110.6%with relative standard deviations (n=6) of 1.2%-13.5%. Conclusion This method is accurate, simple and sensitive, and can meet the requirements for the detection of 3 kinds of enantiomeric residues of chiral pesticides in Pu-erh tea.