分子荧光光谱法检测氨基酸配方和蛋白质水解配方特殊医学用途配方食品中的维生素C含量

Determination of vitamin C content in special medical formula food with amino acids and protein hydrolysate by molecular fluorescence spectrometry

目的优化前处理方法提取氨基酸配方和蛋白质水解配方特殊医学用途配方食品中的维生素C,并采用分子荧光光谱法进行测定。方法通过氧化后的维生素C与邻苯二胺反应生成荧光物质,利用分子荧光光谱进行外标法定量,考察了含有不同乙醇浓度的偏磷酸-乙酸溶液A前处理方法的方法学参数,同时在不同基质的样品中对确定的最佳前处理方法进行了实验验证。结果采用50%乙醇-偏磷酸-乙酸溶液A提取的前处理方法能够有效沉淀氨基酸和多肽,所得处理液易于过滤且滤液澄清。样品在10 mg/100 g、50 mg/100 g和100mg/100g添加水平的加标回收率为90.7%~96.8%,相对标准偏差为2.73%~3.66%。结论 50%乙醇-偏磷酸-乙酸溶液A的前处理方法快速、准确、灵敏,适用于批量测定氨基酸配方和蛋白质水解配方特殊医学用途配方食品中维生素C。

Objective To optimize the pretreatment method for extracting vitamin C from amino acid formula and protein hydrolysis formula for special medical use formula,and detect the vitamin C content by molecular fluorescence spectrometry.Methods The oxidized vitamin C reacted with o-phenylenediamine to form a fluorescent substance,and the molecular fluorescence method was used for quantitative analysis by external standard method.The method parameters of the pre-treatment method of the metaphosphoric acid-acetic acid solution A containing different ethanol concentrations were investigated.The determined optimal pretreatment method was experimentally verified in the sample of the matrix.Results The pretreatment method could effectively precipitate amino acids and polypeptides using 50%ethanol-metaphosphoric acid-acetic acid solution A,and the obtained treatment liquid was easy to filter and the filtrate was clarified.The recoveries of the spiked samples at 10 mg/100 g,50 mg/100 g and 100 mg/100 g were 90.7%-96.8%,and the relative standard deviations were 2.73%-3.66%.Conclusion The pretreatment method of 50%ethanol-metaphosphoric acid-acetic acid solution A is fast,accurate and sensitive,and it is suitable for batch determination of vitamin C in amino acid for mula and protein hydrolysis formula for special medical use formula.