高效液相色谱法测定婴幼儿配方乳粉中维生素C含量的FAPAS能力验证结果与分析

FAPAS Proficiency Testing Result and Analysis of Vitamin C Determination in Infant Formula by HPLC

建立了一种高效液相色谱法测定婴幼儿配方乳粉中维生素C含量的方法,并分析采用该方法参加FAPAS婴幼儿配方乳粉中维生素C含量测定的能力验证的实验结果。样品经偏磷酸溶液提取后,采用TechMate C18-ST(250 mm×4.6 mm,5μm)色谱柱分离,以甲醇-0.02 mol·L^(-1)磷酸二氢铵水溶液(pH=2.0)(2∶98,V∶V)为流动相,流速为0.7 mL·min^(-1),柱温为25℃,检测波长为245 nm,标准曲线法定量。根据该方法及FAPAS组织方所提供的能力验证作业指导书,对能力验证样品及质控样品中的维生素C的含量进行测定,并采用“Z”评分法对结果进行判定。维生素C在5.52~88.24μg·mL^(-1)与峰面积呈良好线性关系,相关系数(r)为0.9997,平均回收率为99.27%,相对标准偏差(RSD)为1.17%。采用加标回收和人员比对实验作为维生素C含量测定的准确度控制手段,能力验证结果|Z|=0.1。该方法操作简单、准确,重复性好,可用于婴幼儿乳粉中维生素C的测定。本方法参加的FAPAS能力验证结果为满意。

To establish a high performance liquid chromatography method for the determination of vitamin C in infant formula and analyze the FAPAS proficiency testing result for vitamin C by the developed method.The samples were ultrasonically extracted with metaphosphate solution and separated on a TechMate C_(18)-ST column(250 mm×4.6 mm,5μm)with the mobile phase consisting of methanol-0.02 mol·L^(-1) ammonium dihydrogen phosphate(pH=2.0)(2∶98,V∶V).The flow rate was 0.7 mL·min^(-1).The column temperature was set at 25℃and the detection wavelength was 245 nm.The standard curve method was used for the quantitative analysis of vitamin C.According to the proposal method and the ability instructions of FAPAS organization,the sample and the quality control sample were determinated for vitamin C,and“Z”scoring method was used to judge the result.Excellent linearity was obtained in the concentration range of 5.52~88.24μg·mL^(-1) for vitamin C with the correlation coefficient(r)of 0.9997.The average recovery was 99.27%with the relative standard derivation(RSD)of 1.17%for vitamin C.Standard addition recovery and researchers comparison were used to control the accuracy of vitamin C content determination. The Z of the capability verification result was 0.1. The method is simple, accurate and reproducible in the detection of vitamin C in infant formula. The result of this verification is satisfactory.