高效液相色谱法测定婴幼儿配方乳粉中酪蛋白磷酸肽的含量

Determination of casein phosphopeptides in infant formulate milk powder by high performance liquid chromatography

目的建立高效液相色谱法测定婴幼儿配方乳粉中酪蛋白磷酸肽含量的方法。方法对婴幼儿配方乳粉样品对应生产批次所采用的酪蛋白磷酸肽原料进行测定,得到准确含量后作为参照品,对婴幼儿配方乳粉样品测定前处理中净化、提取条件进行优化,采用二极管阵列检测器(diode array detector, DAD)定量分析。结果采用混合型阳离子交换(mixed cation exchange, MCX)固相萃取柱、ZORBAX Eclipse AAA色谱柱可得到良好的分离效果,酪蛋白磷酸肽在100~500μg/mL范围内线性关系良好,相关系数r^2为0.9994,检出限为0.140 mg/100 g,加标回收为81.06%~87.78%,相对标准偏差为3.64%。结论该方法前处理操作简单,具有良好的重现性和准确性,能够满足婴幼儿配方乳粉中酪蛋白磷酸肽含量的测定。

Objective To establish a method for the determination of casein phosphopeptide in infant milk powder by high performance liquid chromatography. Methods The raw material of casein phosphopeptide used in the corresponding production batch of infant formula milk powder was determined. After the accurate content was obtained, it was used as the reference material. The purification and extraction conditions in the infant formula milk powder samples pretreatment were optimized, and the quantitative analysis was performed by diode array detector(DAD). Results A good separation effect can be obtained by using mixed cation exchange(MCX) solid phase extraction column and ZORBAX Eclipse AAA column. Casein phosphopeptide had a good linear relationship in the range of 100-500 μg/mL, and the correlation coefficient r2 was 0.9994. The limit of detection was 0.140 mg/100 g, the recoveries of standard addition were 81.06%-87.78%, and the relative standard deviation was 3.64%. Conclusion The method is simple, reproducible and accurate, and can satisfy the determination of casein phosphopeptide in infant formula milk powder.