气相色谱–质谱法测定棉花中苯氧羧酸类除草剂

Determination of Phenoxy Carboxylic Acid Herbicides in Cotton by GC–MS

采用气相色谱–质谱联用法检测棉花中3种苯氧羧酸类除草剂[2,4-D,2,4,5-T,2-甲-4-氯丁酸(MCPB)]的残留量。样品用甲酸酸化的丙酮提取,硫酸催化甲酯化反应,用气相色谱–质谱联用仪测定。采用HPLC法与GC–MS法对提取与衍生化步骤进行优化。2,4-D,2,4,5-T,MCPB 3种化合物在0.075~7.5 mg/kg范围内线性均良好,检出限分别为0.5,0.5,0.8μg/kg,测定结果的相对标准偏差分别为4.1%,4.3%,4.0%(n=5),方法回收率分别为93.6%,95.5%,93.9%。该方法各项指标均可满足检测要求。

A method for detection of2,4-D,2,4,5-T,2-a,-4-butyric acid(MCPB)residue in cotton was established.The samples were extracted by acetone acidized by formic acid,methyl esterification was catalyzed by sulfuric acid,then determined with gas chromatography-mass spectrometry.The extraction and derivatization steps were optimized by HPLC and GC-MS.The results showed that fine linearity was found in the range of0.075-7.5mg/kg for2,4-D;2,4,5-T and MCPB,the detection limits were0.5,0.5,0.8μg/kg,repectively.The relative standard deviations of detection results of2,4-D;2,4,5-T,MCPB were4.1%,4.3%,4.0%(n=5),and the recoveries were93.6%,95.5%,93.9%,respectively.All indexes of this method can meet the requirement of test.