乳制品中那他霉素的超高效液相色谱-串联质谱法快速测定

Rapid Determination of Natamycin in Milk Products by Ultra-performance Liquid Chromatography-Electrospray Negative Ionization Mass Spectrometry

建立了超高效液相色谱-电喷雾串联质谱（UPLC-MS/MS）快速检测乳制品中那他霉素的方法。样品用甲醇提取,以甲醇-水为流动相经反相色谱柱分离后,采用多反应监测（MRM）负离子模式检测,定性离子对为m/z663.6/421.1和m/z663.6/439.1,其中m/z663.6/421.1用于外标法定量。空白样品及其加标实验结果表明：特征离子相对强度比值稳定,无基质干扰,结合保留时间可实现准确的定性定量;方法定量下限为50.0μg/kg;乳制品加标量为50~500μg/kg时,平均回收率为80%~91%,相对标准偏差（n=6）为2.7%~5.2%。方法简单、灵敏、稳定,可满足乳制品中那他霉素的快速检测与确证需要。

A rapid ultra-performance liquid chromatography-tandem mass spectrometric（UPLC-MS/MS） method was developed for the determination of natamycin in milk products.The sample was extracted by methanol,and separated on a reversed-phase UPLC column using a binary eluent under gradient conditions.The analysis of natamycin was performed by tandem mass spectrometry under multiple reaction monitoring（MRM） mode with negative electrospray ionization.Two precursor-product ion pairs of m/z 663.6/421.1 and m/z 663.6/439.1 were selected as qualitation ions and m/z 663.6/421.1 was selected as quantitation ion for the external standard method.The result indicated that the relative intensity of natamycin identification ion pairs in samples was stable,and there was no matrix interference with these confirmatory transitions.Combining with retention time,the method could be used for accurate analysis of natamycin.Under the optimal conditions,the limit of quantitation（LOQ） was 50.0 μg/kg.At the spiking levels of 50-500 μg/kg,the average recoveries of natamycin from milk samples were in the range of 80%-91%,and the relative standard deviations（n=6） were in the range of 2.7%-5.2%.The method show good simplicity,sensitivity and stability,and is suitable for the rapid determination of natamycin in milk products.