采用多壁碳纳米管分散固相萃取-液相色谱-串联质谱法测定茶叶中啶虫脒、噻虫胺、吡虫啉、噻虫啉、噻虫嗪等5种烟碱类农药的残留量。粉碎后的茶叶样品用水浸泡30 min后，用乙腈提取，以多壁碳纳米管作为吸附剂去除杂质。以Agilent C₁₈色谱柱为分离柱，以不同体积比的5 mmol·L^-1乙酸铵-0.1%（体积分数）甲酸溶液和甲醇的混合液为流动相进行梯度洗脱，采用电喷雾正离子源和多反应监测模式检测。5种烟碱类农药的质量浓度均在1.0~20 μg·L^-1内与其对应的峰面积呈线性关系，测定下限（10S/N）均为0.01 mg·kg^-1。以空白样品为基体进行加标回收试验，所得回收率为80.5%~98.7%，测定值的相对标准偏差（n=6）为5.0%~13%。

LC-MS/MS was applied to the determination of residual amounts of 5 neonicotinoid pesticides, i.e. acetamprid,clothiaindin,imidacloprid, thiacloprid and thiamethoxam in tea with dispersive solid phase extraction using multiwalled carbon nanotubes as adsorbent. The tea sample after comminution was immersed with water for 30 min, and then extracted with acetonitrile. Multiwalled carbon nanotubes were used as adsorbent to remove impurities. Agilent C₁₈ chromatographic column was used as stationary phase, and the mixture of 5 mmol·L^-1 ammonium acetate-0.1% (φ) formic acid solution and methanol mixed in different ratios was used as mobile phase in gradient elution. ESI⁺ and multi-reactions monitor mode were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 5 neonicotinoid pesticides were kept in the same range of 1.0-20 μg·L^-1, with the same lower limit of determination (10S/N) of 0.01 mg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 80.5%-98.7%, with RSD's (n=6) in the range of 5.0%-13%.