HPLC-MS/MS法同时测定果蔬中6种植物生长抑制剂残留

Determination of 6 Plant Growth Retardants in Fruits and Vegetables by HPLC-MS/MS

利用高效液相色谱-电喷雾串联质谱（HPLC—ESI MS／MS）技术，建立了果蔬中氯化胆碱、矮壮素、缩节胺、嘧啶醇、多效唑、烯效唑6种植物生长抑制剂残留的检测方法。考察了流动相组分和流动相添加剂对质谱离子化效率的影响以及提取溶剂、提取剂用量和固相萃取柱对萃取效率的影响。在优化条件下，6种目标化合物在1．0～200．0μg／L范围内线性良好（r〉0．99），空白样品中，加标水平为2．0、10．0、50．0μg/kg时，6种目标化合物的平均加标回收率为81％～104％，相对标准偏差均不大于5．0％，方法的检出限为0．15～0．35μg/kg，定量下限为0．47～1．10μg/kg。该方法具有灵敏度高、选择性好、回收率高且稳定等优点，用于实际果蔬样品中植物生长抑制剂的测定，结果满意。

A comprehensive analytical method based on high performance liquid chromatography - eleetrospray ionization tandem mass spectrometry （HPLC - ESI MS/MS） under positive ionization mode was developed for the determination of 6 plant growth retardants （ PGRs ） residues, including choline chloride, chlormequat chloride, mepiquat chloride, ancymidol, paclobutrazol and unieonazole in fruits and vegetables. The samples were extracted with methanol by ultrasonic wave assistant extraction（ UAE ）. The extract was purified and concentrated by solid-phase extraction （SPE） with Waters Oasis HLB column （3 mL, 60 mg）. The separation of the target compound was performed with Thermo Hypersil Gold aQ（2. 1 mm× 150 mm, 3 μm） column by gradient elution. The identification of 6 PGRs was carried out by ESI under the positive-ion mode. Effects of mobile phase and additives on ionization were investigated. Effects of the types and amounts of extraction solvents and the types of SPE column were also studied. Under the optimal conditions, the calibration curves of 6 PGRs were linear in the range of 1.0 -200. 0 μg/L with correlation coefficients（r） more than 0. 99. Recoveries of 6 PGRs at three spiked concentration levels of 2.0, 10.0, 50.0μg/kg ranged from 81% to 104% with relative standard deviations no more than 5.0%. The detection limits（LOD） were in the range of 0. 15 -0. 35 μg/kg and the quantitative limits（LOQ） were 0. 47 - 1.10 μg/kg. The established method has the advantages of high sensitivity, nice selectivity and low detection limit, and was applied in the determination of PGRs in fruits and vegetables with satisfactory results.