全自动GPC-SPE联合净化气相色谱-质谱检测小龙虾中有机氯类农药残留

Determination of OCPs in Crayfish by GPC-SPE/GC-MS

建立了气相色谱-质谱定量测定小龙虾中20种有机氯类混合农药残留的方法，并对提取溶剂、净化方法等分析条件进行优化。最终采用乙腈提取样品，乙酸乙酯-环己烷（1：1）定容，凝胶渗透色谱（GPC）和氨基固相萃取柱（Carb／NH：）联合净化，以GC—MS检测，选择离子扫描（SIM）模式监测目标化合物的特征离子进行定性定量分析。20种化合物在0．01～1．0mg／L范围内线性关系良好（r〉0．994），各有机氯的检出限（S／N=3）为0．1—1．5μg/kg。分别对虾黄和虾尾进行5，10，20μg/kg3个水平的加标实验，方法的回收率为71．3％～117．3％，相对标准偏差为0．6％-7．5％。该方法选择性好、灵敏度高，样品净化效果好，适用于小龙虾中有机氯类农药的多残留测定。

A method was established for the quantitative determination of 20 organochlorine pesticides （OCPs） in crayfish by gas chromatography and mass spectrometry（GC -MS）. The preparation and analytical conditions, such as extraction solvent, purification method and other analytical conditions were optimized. The samples were extracted with acetonitrile, and kept in constant volume with ethyl acetate- cyclohexane（ 1 ： 1 ）. The extract was purified by gel permeation chromatography （GPC） combined with solid-phase extraction （SPE） , and determined by GC - MS under selective ion scan （SIM） mode. Under the optimum conditions, the calibration curves of the compounds were linear in the range of 0. 01 - 1.0 mg/L with correlation coefficients higher than 0. 994, and the limits of detec- tion （ LOD, S/N = 3 ） were in the range of 0. 1 - 1.5 μg/kg. The recoveries of target compounds in crayfish yellow and meat samples at three spiked concentration levels of 5, 10, 20 μg/kg were in the range of 71.3% -117.3%, with RSDs（n=6） of 0.6% -7.5%. The method is sensitive, accu- rate and simple, and could be applied in the determination of 20 OCPs in crayfish.