牛奶中氯唑西林残留量的高效液相色谱法测定

为建立高效液相色谱法测定牛奶中氯唑西林残留的方法,牛奶样品用乙腈沉淀蛋白,三氯甲烷反萃取,有机相旋干用流动相溶解,正己烷除脂。0.02mol/L磷酸二氢钾溶液(pH 5.0)-乙腈(68∶32)比例为流动相,C18反相色谱柱分离,紫外检测。结果氯唑西林在15μg/kg～1 000μg/kg范围内呈现良好的线性关系,相关系数大于0.999 0;在15、30、60μg/kg三个添加水平,氯唑西林在牛奶中的平均回收率为70.25%～94.38%,批内变异系数小于8.34%,批间变异系数小于3.52%。方法检出限为5μg/kg,定量限为15μg/kg。表明该检测方法简单、灵敏、可靠,适用于牛奶中氯唑西林残留的分析检测。

Determination of Cloxacillin Residues in Milk by High-performance Liquid Chromatography

A analytical method for the determination of cloxacillin in milk by high-performance liquid chromatography was established.Milk were deproteinized with acetonitrile,and back-extracted with chloroform,and the organic phase was evaporated until dryness using a rotary evaporator,metered volume with mobile phase,defatted by n-hexane.The mobile phase was 0.02 mol/L KH2PO4(pH 5.0)-acetonitrile(68∶32).The analyte is detected by UV absorptive spectroscopy after separation was achieved on a C18 RP column.The range of linearity is 15 μg/kg-1 000 μg/kg,and the relevant coefficient is more than 0.999 0.The mean recoveries from milk fortified at 15,30,60 μg/kg are from 70.25% to 94.38%,and coefficient of intra-day and intre-day variation are respectively less than 8.34% and 3.52%.The limit of detection(LOD) is 5 μg/kg,and the limit of qualification(LOQ) is 15 μg/kg.In conclusion,the established method is simple,sensitive and reproducible for the detection and analysis of cloxacillin residues in milk.