液相色谱法测定奶粉中三聚氰胺的方法优化.pdf

※分析检测 食品科学 2009, Vol. 30, No. 14 22 7 液相色谱法测定奶粉中三聚氰胺的方法优化 李 燕，柴 勇，龚久平，刘吉振* ，易志坚，洪云菊，高 静 (农业部农产品质量安全监督检验测试中心(重庆) ，重庆市农业科学院农业质量标准检测技术研究所，重庆 4 00055) 摘 要：优化了反相高效液相色谱测定奶粉中三聚氰胺的方法。样品制备：采用乙酸铅对奶粉中的蛋白质进行沉 淀，用1% 的三氯乙酸代替水对阳离子交换固相萃取柱进行活化和洗涤；色谱条件：提高缓冲离子对试剂p H 值 为3.0 ，增加流动相中乙腈比例。结果：用外标法定量分析，标准曲线的相关系数为0.9997 ，平均回收率为95.8%～ 10 1.5% 。证明优化后的方法具有较好的回收率和重现性，可以准确地测定奶粉中的三聚氰胺。 关键词：三聚氰胺；液相色谱；奶粉；优化 Optimization of RP-HPLC Determination of Melamine in Milk Powder LI Yan ，CHAI Yon g ，GONG Jiu -p in g ，LIU Ji-zhen * ，YI Zhi-j ian ，HONG Yun-j u ，GA O Jing (Chongqing Supervision and Testing Center for Agricultural Products Quality and Security, Ministry of Agriculture, Institution of Agricultural Quality Standard and Testing Technology, Chongqing Academy of Agricultural Sciences, Chongqing 400055, China) Abstract ：The RP-HPLC method for determining melamine in milk powder has been developed. However, the differences in chromatography instrument and column performance and status may lead to the occurrence of disagreement among determina- tion results from different labs. To enhance the accuracy, reproducibility and efficiency of melamine detection by HPLC, sample preparation and chromatographic condition s were optimized in the present study. Milk powder samples were extracted using 1% trichloroacetic acid and 2% lead acetate solution in an ultrasonic field and cleaned up on an SCX solid phase extraction column which was activated and leached using 1% trichloroacetic acid instead of water. The optimization of chromatographic conditions was achieved by increasing the ion-pairing buffer containing 10 mmol citric acid and 10 mmol heptane-1-sulfonic acid sodium salt to pH 3 and adjusting the proportion of acetonitrile in the mobile phase consisting of it and t