气质联用选择离子一次测定食品中32种农药和除草剂

Determination of 32 weedicides and pesticides in foods by gas chromatography-mass spectrometry and selected ion monitoring

目的：建立一种测定食品中有机磷、有机氯、氨基甲酸酯和除草剂农药残留的气相色谱质谱方法。方法：本法采用丙酮、二氯甲烷提取,40℃水浴旋转蒸发近干,以Envi-Carb柱和Sep-Pak-NH2柱净化,以气相色谱-质谱选择离子监测方式分析检测有机磷、有机氯、氨基甲酸酯和除草剂等32种农药残留。结果：所有32种农药均在37 m in内流出,分离良好,农药标准的线性范围在0.05-1.0μg/m l,相关系数r均在0.99以上,低、高二种浓度加标回收率均在89%-98%之间,相对标准偏差均小于10%,方法最低检出限为0.005 mg/kg（S/N=3）。结论：方法选择性强,适合于食品中有机磷、有机氯、氨基甲酸酯和除草剂农药残留的测定,且准确度好,精密度高,可快速一次检测32种农药,达到残留量检测中所要求的检测浓度水平。

Objective：To establish a method for determination of organophosphorus, organochlorine, carbamate and weedicide pesticides in foods by gas chromatography - mass spectrometry （ GC - MS） and selected ion monitoring （ SIM ）. Methods： The pesticides were extracted with acetone and dichloromethane. The extract was warmed with water at 80℃, circumrotated and evaporated until it was nearly dry. Then it was cleaned - up by Envi - Carb column and Sep - Pak - NH2 column. The analysis was performed by GC - MS and SIM. Retention time and specific ions were used to confiIm the pesticides. Results：The calibration curves of 32 pesticides were linear（ correlation coefficient r 〉0. 99） within the range of 0.05 - 1.0 μg/ml. The recoveries were 90% 96%, the relative standard deviations （RSD） of the method was 〈 10% for each case, and the limit of determination（ LOD）, defined in terms of 3 times baseline noise, was 0. 005 mg/kg. Conclusion： The method is suitable for determining pesticides in foods with satisfactory sensitivity, accuracy and precision.