提出了高效液相色谱-串联质谱法同时测定茶叶中5种农药,即唑螨酯、三唑酮、鱼藤酮、除虫脲和萎锈灵残留量的方法。样品经乙腈和固体硫酸镁及氯化钠提取,以Shiseido C18 MGII色谱柱为分离柱,以不同体积比的乙腈和0.005 mol·L-1乙酸铵溶液的混合液为流动相进行梯度洗脱。采用电喷雾正离子源多反应监测模式进行质谱测定。5种农药的质量浓度均在1.00~20.0 μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)为0.005 mg·kg-1。在0.005,0.010,0.020 mg·kg-1 3个浓度水平上进行加标回收试验,回收率在88.2%~104%之间,测定值的相对标准偏差(n=10)在4.8%~13%之间。

A method of HPLC-MS/MS for the determination of 5 pesticides, i.e., fenpyroximate, rotenone, triadimefon, diflubenzuron and carboxin in tea was proposed. The sample was extracted with acetonitrile and solid MgSO4 and NaCl. Shiseido C18 MGII column was used as stationary phase, and mixtures of acetonitrile and 0.005 mol·L-1 ammonium acetate solution in different ratios were used as mobile phase in gradient elution. ESI+ and multi-reaction monitoring were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 5 pesticides were kept in the same range of 1.00-20.0 μg·L-1, with detection limits (3S/N) of 0.005 mg·kg-1. Tests for recovery were made at the concentration levels of 0.005, 0.010 and 0.020 mg·kg-1, giving values of recovery and RSD′s (n=10) in the ranges of 88.2%-104% and 4.8%-13% respectively.