婴幼儿配方食品和乳粉中核苷酸的测定方法

Research on determination of nucleotides in infant formula food and milk powder

采用碱性磷酸酶先将样品中的核苷酸酶解为核苷,然后用高效液相色谱法测定婴幼儿配方食品和乳粉中核苷酸总量。试样经水提取,通过调pH值沉淀蛋白质,样液中的核苷酸经碱性磷酸酶水解生成核苷,再通过快速加热的方式终止酶解反应,同时进一步去除杂质,用磷酸二氢钾及甲醇作流动相,用普通C18色谱柱,采用梯度洗脱的模式对5种核苷进行有效分离。本方法回收率在92.4%～103.7%之间,相对标准差2.0%～8.0%。核苷酸各组分定量限:CMP为0.6 mg/100g,UMP为0.7 mg/100g,IMP+AMP为0.5 mg/100 g,GMP为0.4 mg/100 g(均为质量分数)。该方法简便、快速、准确,完全能满足婴幼儿配方食品中核苷酸总量测定的要求。为核苷酸检测开辟了全新的途径。

We first employ alkaline phosphatase to hydrolyze nucleotides to the corresponding nucleosides and establish a method for which detects the total nucleotides in infant formula food and milk powder using HPLC.The sample is extracted by water,and eliminated of protein by adjusting pH.Then the nucleotides in sample are degraded into nucleosides.This enzyme has been heat deactivated in order to stop reaction and remove impurities further.The chromatographic separation was achieved using a C18 column and a gradient elution with a mixture of two solvents,which effectively separate five kinds of nucleosides.The range of recovery rates of is 92.4% ~103.7% and the range of relative standard deviations is 2.0% ~8.0%.The detection limits for these nucleotides are ：CMP 0.6 mg/100 g、UMP 0.7 mg/100 g、IMP＋AMP 0.5 mg/100 g and GMP 0.4 mg/100 g.Conclusion： The method which offers a new way to detect the nucleotides is simple,rapid and accurate and it can completely meet the detection of total nucleotides in infant formula food and milk powder.