奶粉中链霉素与双氢链霉素残留量的超高效液相色谱-串联质谱法测定

Determination of Streptomycin and Dihydrostreptomycin Residues in Milk Powder by UPLC-MS/MS

建立了奶粉样品中链霉素与双氢链霉素残留量的超高效液相色谱-串联质谱测定方法。样品用ED-TA-Na2缓冲溶液提取,弱阳离子交换树脂固相萃取柱（WCX）净化后,采用HILIC色谱柱（50 mm×2.1 mm,1.7μm）分离,以乙腈和含0.3%甲酸的100 mmol/L甲酸铵溶液梯度洗脱,多反应监测模式测定,外标法定量。在优化实验条件下,链霉素和双氢链霉素在2.0~50.0μg/L质量浓度范围内线性关系良好,检出限均为0.01 mg/kg,方法的回收率为74%~110%,相对标准偏差均不大于9.4%。该方法简便、快速、实用、准确,能够满足奶粉中链霉素和双氢链霉素残留量的检测要求。

An ultra-high performance liquid chromatography-tandem mass spectrometric（UPLC-MS/MS） method was developed for the determination of streptomycin and dihydrostreptomycin residues in milk powder.Samples were extracted with EDTA-Na2 buffer and cleaned up on a weak cation exchange SPE column（WCX）.The extract was separated on a HILIC column（50 mm×2.1 mm,1.7 μm） using acetonitrile-100 mmol/L ammonium formate solution containing 0.3% formic acid as mobile phase with gradient elution.The detection of streptomycin and dihydrostreptomycin was carried out by MS/MS under multiple reation monitoring（MRM） mode.An external standard method was used for quantitative analysis.Results indicated that the calibration curves for streptomycin and dihydrostreptomycin were linear in the range of 2.0-50.0 μg/L,and the detection limits were both 0.01 mg/kg.The recoveries of streptomycin and dihydrostreptomycin ranged from 74% to 110% with relative standard deviations no more than 9.4%.The method was simple,rapid and practical,and could meet the requirements for determination of streptomycin and dihydrostreptomycin residues in milk powder.