高效液相色谱法快速检测茶叶中三氯杀螨醇

Determination of dicofol residues in tea by high performance liquid chromatography

建立了茶叶中三氯杀螨醇残留量的高效液相色谱快速检测方法。选择丙酮:正己烷(1:2,V/V)对不同茶叶中三氯杀螨醇农药残留进行提取,经浓硫酸净化,1 mL甲醇定容后供高效液相色谱检测。Agilent Acclaim TM 120 C_(18)色谱柱(250×4.6,5μm)分离,流动相为乙腈-水(85:15,V/V)混合溶剂,梯度洗脱。对不同茶叶类型,提取、净化条件进行考察优化。结果表明,标准工作曲线,在0.02~5 mg/kg范围内,三氯杀螨醇线性关系良好(r为0.9999),方法定量限为0.05 mg/kg。在绿茶、红茶、黄茶、青茶、白茶、黑茶6种茶叶中4个添加水平0.05,0.1,5,50 mg/kg的平均回收率范围分别为91.8%~108.3%,88.8%~102.5%,83.7%~94.3%,80.9%~84.2%,相对标准偏差在1.2%~14%之间(n=6)。

A rapid method for the determination of dicofol residues in tea by high performance liquid chromatography（ HPLC） was established. The pesticide residues in different tea were extracted by acetone： n-hexane（ 1： 2,V： V）,purified by concentrated sulfuric acid and fixed in 1 mL of methanol for HPLC. The mobile phase consisted of acetonitrile-water（ 85： 15,V： V） and gradient elution. The mobile phase was separated on an Agilent Acclaim TM 120 C18column（ 250 × 4. 6,5 μm）. Different tea types,extraction and purification conditions were optimized. Under the optimized condition,good linear relationships were obtained in the range of 0. 02 - 5 mg/kg（ r = 0. 9999）. The limit of quantitation was 0. 05 mg/kg. The average recoveries for green tea,red tea,yellow tea,cyan tea,white tea and black tea which were spiked with 0. 05,0. 1,5 and 50 mg/kg of dicofol were 91. 8% -108. 3%,88. 8% - 102. 5%,83. 7% - 94. 3% and 80. 9% - 84. 2%,respectively. The relative standard deviations ranged from 1. 2% to 14%（ n = 6）. The method is simple,rapid and high sensitivity.