气相色谱-串联质谱双内标法测定茶叶中53种农药残留

建立了气相色谱-串联质谱（GC-MS/MS）动态多反应离子监测（dMRM）模式，结合串联双色谱柱检测茶叶中53种农药残留量的分析方法。样品中加入QuEChERS缓冲盐，用乙腈提取，采用石墨化炭黑/氨基柱（ENVI-Carb/NH₂）净化。为减少农药在GC-MS/MS分析中基质效应的影响，在标准溶液中加入古洛糖酸内酯和山梨醇作为保护剂，用蒽醌-D8和磷酸三苯酯作双内标定量。结果表明，除了氯氰菊酯的线性范围是40~1000 μg/L外，其他52种农药的线性范围均为20~500 μg/L，线性关系良好，相关系数均大于0.99；有28种农药的定量限（LOQ）小于10 μg/kg，其余25种农药的定量限为10~20 μg/kg；加标回收率为72.5%~130.9%；相对标准偏差（RSD）为0.4%~19.4%。该方法能有效地减少茶叶在GC-MS/MS上的基质效应，操作简单快速，灵敏度和选择性高，适用于农药残留的日常检测。

Determination of 53 pesticide residues in tea by gas chromatography-tandem mass spectrometry and double internal standard method

A gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) method with tandem double columns was established for the determination of 53 pesticide residues in tea. The sample was extracted by acetonitrile with buffering salts of QuEChERS method, cleaned up with an ENVI-Carb/NH₂ solid-phase extractant, and determined by GC-MS/MS. To reduce the matrix effect in GC-MS/MS, gulonic acid lactone and sorbitol were added to the standard solutions as protectants; additionally, anthraquione-D8 and triphenyl phosphate were used as double internal standards. The linear ranges were from 20 to 500 μg/L for 52 pesticides, and from 40 to 1000 μg/L for cypermethrin, with correlation coefficients higher than 0.99. The limits of quantification (LOQs) of 28 pesticides were less than 10 μg/kg, and the LOQs of the other 25 pesticides ranged from 10 to 20 μg/kg. The recoveries were in the range 72.5%-130.9%, and the relative standard deviations (RSDs) were in the range 0.4%-19.4%. This method is simple, rapid, sensitive, and reliable for the simultaneous identification and quantification of multiple residues in tea.