婴幼儿配方食品和乳粉中维生素C的测定

Determination of vitamin C in foods for infants and young children, milk and milk products

目的建立一种前处理简单、仪器条件稳定、准确高效的婴幼儿配方食品和乳粉中维生素C的检测方法。方法用含有三(2-羧乙基)膦(TCEP)的三氯乙酸(TCA)对样品中的维生素C进行提取,C18柱色谱分离,流动相为含TCEP与癸胺作为离子对试剂和pH 5.4的醋酸钠的混合水溶液,然后在紫外检测器265 nm处进行检测。结果本方法的相对标准偏差(n=6)在0.36%~3.2%之间,平均回收率为88.5%~97.9%,线性相关系数r^2大于0.9999。结论本方法实验前处理简单,干扰因素少;仪器条件稳定,灵敏度高,重复性好;适合婴幼儿配方食品和乳粉复杂基质样品的测定。

Objective An accurate and efficient method was developed in order to solve problems existed in the detection of vitamin C in milk powder and formula foods for infant and young children, which had simple pretreatment and stable instrument conditions. Methods Vitamin C was extracted from samples by trichloroacetic acid（TCA） with tris（2-carboxyethyl） phosphine（TCEP） as a reducing agent, and then determined by ultraviolet detector at 265 nm. Samples were separated by a C_（18） column with sodium acetate（p H=5.4） as the eluent, combined with TCEP and decylamine as an ion-pairing agent. Results The relative standard deviation（n=6） of this method was between 0.36%~3.2%, the average recovery was 88.5%~97.9%, and the linear correlation coefficient was greater than 0.9999. Conclusion The established method is simple with less interference factors, and instrument conditions are stable, sensitive with good repeatability, which is suitable for the detection of vitamin C in complex sample matrix such as infant formula milk powder.