提出了在线富集毛细管区带电泳法测定牛奶中三聚氰胺的含量.系统地考察了毛细管区带电泳工作条件,选定的试验条件为:① 磷酸盐缓冲溶液浓度为20 mmol·L-1;② pH值为3.0;③ 运行电压为30 kV;④ 检测波长为208 nm.在优化的试验条件下,三聚氰胺在8 min内达到基线分离,其线性范围为0.83~106.70 mg·L-1,检出限(3S/N)为0.2 mg·L-1.在制备供试液后不同时间进样测定,三聚氰胺迁移时间的相对标准偏差为0.72%,峰面积的相对标准偏差为1.02%,结果表明样品在8 h内稳定.

A method for the determination of melamine in milk by capillary zone electrophoresis (CZE) with on-line enrichment was proposed.Through systematic study on the conditions of separation by CZE,optimum conditions were found as follows: ① concn.Of PBS: 20 mmol·L-1;② pH values of PBS: 3.0;③ moving voltage: 30 kV;④ wavelength of detection: 208 nm.Linear relationship between values of detection signal and concentration of melamine was obtained in the range of 0.83-106.70 mg·L-1.Detection limit (3S/N) found was 0.2 mg·L-1.Under the optimum condition,melamine was completely separated from the baseline within 8 min.Values of RSD′s of migration times and peak area were 0.72% and 1.02%,and as proved by the results obtained,the sample was stable within 8 h.