反相液相色谱法测定烟叶中精甲霜灵残留

Determination of Residual Metalaxyl-M in Tobacco by Reversed-phase Liquid Chromatography

建立了1种用反相液相色谱法测定烟叶中精甲霜灵残留量的方法。优化和选择了烟叶样品的前处理条件,样品经正己烷+丙酮(体积比为2∶3)振荡提取,二氯甲烷液–液分配萃取,中性氧化铝层析柱净化。采用C18色谱柱,以甲醇+水为流动相进行梯度洗脱,紫外检测器于220nm波长下检测。结果表明,该方法在0.1～25.0 mg/L范围内呈良好的线性关系,相关系数为0.999 9。在样品的加标水平为0.2,1.0,2.0 mg/kg时,平均回收率为77.1%～82.3%,相对标准偏差在4.3%～5.1%之间,方法的最低检测浓度为0.04 mg/kg。该方法符合农药残留检测技术的要求,且简便、可靠,适用于烟草中精甲霜灵残留量的测定。

A reversed-phase liquid chromatographic（RP-LC） method was established for determination of metalaxyl-M in tobacco.After optimization of different pretreatment conditions,metalaxyl-M was extracted with n-hexane ＋ acetone（2∶3,V/V）,cleaned up on a column of Al2O3,then determined with a column C18（150 mm×4.6 mm,5 μm） and UV detector at 220 nm,using methanol ＋ water as mobile phase for gradient elution.A line was obtained in the concentra-tions of 0.1-25.0 mg/L with the linear correlation coefficient of 0.999 9.The recoveries were performed at 0.2,1.0,2.0 mg/kg fortification levels,and the average recoveries ranged from 77.1% to 82.3% with the relative standard deviations of 4.3%-5.1%,and the limit of quantification was 0.04 mg/kg for metalaxyl-M.This method applied to the requirements on metalaxy-M residue determination in tobacco.