农产品中甲草胺残留量的气相色谱-质谱检测

建立了玉米、花生、菠菜、柑橘4种不同类型农产品中甲草胺残留量的检测方法。样品先用丙酮-水(体积比为8∶2)提取,经二氯甲烷液-液分配,再用凝胶色谱(GPC)和固相萃取(SPE)去除色素和提取待测物,最后采用气相色谱-质谱测定,外标法定量。甲草胺的添加水平为0.010～0.200 mg/kg时,平均回收率为86.0%～98.2%;相对标准偏差为5.1%～6.7%;方法的测定低限为0.010 mg/kg。

Determination of Alachlor Residue in Agricultural Products

A method of the determination of alachlor residue in agricultural products was developed. Four different kinds of objects, corn, peanut, spinach, and orange were selected as representatives of main agricultural products. The sample was extracted with acetone-water (8:2, v/v). The extract was partitioned with dichloromethane, cleaned up by gel permeation chromatography (GPC) and solid phase extraction (SPE) in order to completely separate colorants from alachlor in the sample. The eluate was evaporated under vacuum to nearly dry and diluted with acetone to a definite volume. The solution was determined and identified by gas chromatography-mass spectrometry (GC-MS) using external standard method. The recoveries were 86.0%-98.2%, and relative standard deviations were 5.1%-6.7% with spiked at 0.010-0.200 mg/kg of alachlor in blank samples. The limit of quantification of this method was 0.010 mg/kg.