建立快速、经济测定乳及乳制品中三聚氰胺的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法。乳及乳制品样品中加入乙腈-水溶液,通过超声波提取和二氯甲烷液液萃取除去蛋白质、脂肪等杂质,进一步稀释后直接进样。经超高效液相色谱(UPLC)快速分离,采用电喷雾正离子(ESI+)多反应监测模式(MRM),实现对三聚氰胺的定性和外标法定量。乳及乳制品样品在1.2 min内完成分析,且具有良好的线性关系(r=0.999 1);方法检出限和定量限(LOQ)分别为0.005 mg/kg、0.017 mg/kg;在0.5～100μg/L的基质添加浓度范围内,平均回收率为91.3%～97.1%,相对标准偏差(RSD)小于9.03%。

A rapid and economic ultra performance liquid chromatography-tandem mass spectrometry method is developed and validated for the determination of melamine in milk and milk products.The method includes a simple acetonitrile-water extraction,and ultrasound treatment and dichloromethane liquid-liquid extraction to remove protein and fat.The purified extract is further diluted before injection on ACQUITY UPLC BEH HILIC.A positive ion electrospray ionization(ESI+) and multiple reaction monitoring mode(MRM) are then applied.The samples are quantified by external standard method.A total analysis was done within 1.2 min with a good linear relationship(r>0.9991).The limit of detection and the limit of quantification were 0.005 and0.017 mg/kg,respectively.The spiked recoveries are within 91.3%~97.1% at the spiked levels of 10~400 μg/L for melamine with relative standard deviation(RSD) below 9.03%.This method is rapid,economic,accurate and sensitive,suitable for screening and detection melamine in milk and milk products.