HPLC-PAD外标法及UPLC-MS/MS内标法测定乳及乳制品中三聚氰胺的含量

HPLC-PAD with External Standard Quantification and UPLC-MS/MS with Internal Standard Quantification for the Determination of Melamine in Milk and Milk Products

分别建立高效液相色谱-二极管阵列法(HPLC-PAD)、超高压液相色谱-串联质谱法(UPLC-MS/MS)测定乳及乳制品中三聚氰胺含量的方法。利用HPLC-PAD外标法进行样品中三聚氰胺的初筛,利用UPLC-MS/MS法进行确证,以13C315N3-三聚氰胺为同位素内标定量。乳制品经乙腈、乙酸锌、盐酸溶液提取,质谱检测时,样品再经MCX固相萃取柱富集净化。HPLC-PAD法的定量限为4mg/kg,UPLC-MS/MS的定量限为0.05mg/kg;HPLC-PAD的添加回收率为95.7%～102.3%,UPLC-MS/MS的添加回收率为91.3%～95.7%(基质匹配曲线校正),两种方法的相对标准偏差(RSD)分别为1.98%～4.51%,1.60%～3.27%。

A method for the determination of melamine in milk and milk products was established by joint use of HPLC-PAD with external standard quantification and UPLC-MS/MS with internal standard quantification.Melamine content of samples was primarily analyzed by HPLC-PAD with external standard quantification,and then confirmed by UPLC-MS/MS and quantified by internal standard method using13C315N3.Samples were extracted with acetonitrile and then the extract was added with zinc acetate and hydrochloric acid and cleaned up using an MCX solid-phase extraction cartridge prior to UPLC-MS/MS analysis.The limit of quantification of the HPLC-PAD method was 4 mg/kg,while that of the UPLC-MS/MS method was 0.05 mg/kg.The average recovery rates of melamine from milk powder,liquid milk and milk cream across three spike levels as determined by the HPLCPAD and UPLC-MS/MS methods were 95.7%–102.3% and 91.3%–95.7%（matrix match calibration）,respectively,and the relative standard deviations were 1.98%–4.51% and 1.60%–3.27%.