以α-甲基-色氨酸为内标物,建立了碱水解-高效液相色谱法测定婴幼儿配方乳粉及特殊医学用途婴儿配方食品中色氨酸含量的方法。样品经碱溶液水解,C18柱分离,荧光检测器检测;再通过内标法定量,校正水解过程色氨酸的损失,降低基质之间的差异,提高定量结果的准确性;对不同种类的婴幼儿配方食品进行加标回收实验,样品的回收率为92.5%~97.4%,相对标准偏差<3.11%,实验室间偏差＜6.7%。方法操作简单、准确度高,重复性好,适用于婴幼儿配方乳粉及特殊医学用途婴儿配方食品中色氨酸的准确定性定量。
A method based on alkaline hydrolysis coupled with high-performance liquid chromatography (HPLC) was developed for the determination of tryptophan in infant formula and infant formula for special medical purposes with α-methyl tryptophan as the internal standard. The sample was hydrolyzed by alkali solution and separated by C18 column. Then it was detected by a fluorescence detector. The internal standard method could correct the loss of tryptophan during hydrolysis, reduce the difference between substrates and improve the accuracy of quantitative results. The recovery was in the range of 92.5%-97.4%, and the relative standard deviation (RSD) was less than 3.11%. Furthermore, the relative standard deviation between laboratories was less than 6.7%. The method was simple, accurate and reproducible and could be applied for the accurate qualitative and quantitative determination of tryptophan in infant formula and infant formula for special medical purposes.
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