气相色谱法测定蔬菜水果中三氯杀螨醇残留量

Gas Chromatographic Determination of Dicofol Residue in Vegetables and Fruits

建立测定蔬菜和水果中三氯杀螨醇农药残留的气相色谱方法。选择10种蔬菜、水果样品,经丙酮正己烷混合试剂提取后,过弗罗里固相萃取柱净化、碱解,用带有电子捕获检测器的气相色谱仪测定,外标法定量。通过对该方法的灵敏度、准确度和精密度进行实验,三氯杀螨醇的最低检出限为0.005mg/kg,各水平的添加回收率范围为70.23%～98.10%,变异系数为3.21%～10.12%,所建立的蔬菜、水果中三氯杀螨醇残留量的测定方法满足国家标准对食品中农药残留测定的要求。

A method using gas chromatography （GC） was established for the determination of dicofol residue in vegetables and fruits. Samples were extracted with a mixture of acetone and n-hexane. The resulting extract was then cleaned up on a Florisil column and treated with a mixture of absolute ethanol and aqueous potassium hydroxide solution. The n-hexane （upper layer） was harvested and washed with 20 g/L aqueous sodium sulfate solution twice prior to the injection into a GC system equipped with an electron capture detector. The external standard method was adopted for dicofol quantification. The figures of merit of the developed method such as sensitivity, accuracy and precision were evaluated. The limit of detection for dicofol was 0.005 mg/kg. Average recoveries for dicofol in 10 species of real samples separately spiked at 3 levels in 10 replicates each were ranged from 70.23% to 98.10%, with a RSD range between 3.21% and 10.12%. This method may satisfy the requirements of the national standards for pesticide residue determination.