超高效液相色谱-串联质谱法同时测定茶叶中11种植物生长调节剂及吡虫啉、啶虫脒的残留

摘要

建立了超高效液相色谱-串联质谱法同时快速测定茶叶中11种植物生长调节剂(PGRs)及吡虫啉、啶虫脒的方法.样品经乙腈-甲酸溶液(99∶1, V/V)均质提取,采用C18、强阴离子交换剂(SAX)、 N-丙基乙二胺(PSA)和无水MgSO4混合吸附剂分散萃取处理,以HSS T3色谱柱分离,采用电喷雾(ESI)正负离子同时扫描和可编程多反应监测模式(SMRM)检测,基质匹配溶液外标法定量.6-苄氨基嘌呤、多效唑、烯效唑、氯吡脲、甲哌啶、吡虫啉、啶虫脒在1～200 μg/L和2,4-二氯苯氧乙酸、对氯苯氧乙酸、赤霉素、吲哚乙酸、萘乙酸、吲哚丁酸在5～1000 μg/L范围内线性良好(R2>0.99).13种化合物加标回收率在73.1％～108.9％之间,RSD (n=6)值在0.6％～8.0％之间,方法检出限(LOD, S/N=3)和定量限(LOQ, S/N=10)分别为0.18～9.68 μg/kg和0.61～32.26 μg/kg.本方法简便、稳定、灵敏,能够满足实际检测需求.%An efficient method for the analysis of multiclass plant growth regulators and pesticide (imidacloprid, acetamiprid) residues in tea was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with acetonitrile/formic acid (99∶1, V/V) solution, cleaned up with four sorbents including C18, strong anion exchanger (SAX), primary secondary amine (PSA) and anhydrous MgSO4. The compounds were separated on a HSS T3 column under positive/negative electrospray ionization mode, detected by scheduled multiple reaction monitoring (SMRM), and quantified by matrix-matched external standard curves. All pesticide residues showed good linearity in the concentration range of 1-200 μg/L (6-benzylaminopurine, paclobutrazol, uniconazole, forchlorfenuron, mepiquat chloride, imidacloprid, acetamiprid) or 5-1000 μg/L (2,4-dichlor-ophenoxyacetic acid, 4-chlorophenoxyacetic acid, indole-3-acetic acid, gibberellic acid, 1-naphthaleneacetic acid, indole-3-butyric acid) , with correlation coefficient (R2≥0.99). Limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) were 0.18-9.68 μg/kg and 0.61-32.26 μg/kg, respectively. In addition, the spiked recoveries of tea samples were 73.1％-108.9％, and RSDs were 0.6％-8.0％. This method was applied to commercial samples, and all the detections were confirmed by acquiring transitions for each pesticide in the samples.