Draher Jonathan
Abbott Laboratories, 3300 Stelzer Rd, Columbus, OH 43219.
J AOAC Int. 2019 Sep 1;102(5):1567-1573. doi: 10.5740/jaoacint.18-0399. Epub 2019 Jul 18.
A multi-laboratory study was completed with AOAC First Action Method 2017.03, . Ten laboratories from seven countries participated in the multi-laboratory study. Each laboratory analyzed 14 infant, pediatric, and adult nutritionals in duplicate. Product matrices analyzed included milk, soy, partially hydrolyzed milk, partially hydrolyzed soy, and elemental-based infant formula powders, milk-based infant formula ready-to-feed (RTF) liquids, adult low-fat powders, and adult high-fat and high-protein ready-to-drink nutritionals. Tryptophan was released from the intact protein in product matrices with a combination of proteolytic enzymes found in pronase. Following proteolysis, tryptophan was quantitated by reverse-phase isocratic HPLC and fluorescence detection. Prepared samples were injected onto a C8 HPLC column with a methanol/0.05 M phosphate buffer mobile phase. Overall for tryptophan, repeatability averaged 2.1% relative SD (RSD) with a range of 0.9-3.6% RSD, and reproducibility averaged 4.2% RSD with a range of 3.0-9.9% RSD. Repeatability (SMPRs®) were met for 13 of the 14 matrices and reproducibility SMPRs were met for 11 of the 14 product matrices analyzed.
采用AOAC首次采用方法2017.03完成了一项多实验室研究。来自七个国家的十个实验室参与了该多实验室研究。每个实验室对14种婴儿、儿童和成人营养产品进行了双份分析。所分析的产品基质包括牛奶、大豆、部分水解牛奶、部分水解大豆和基于元素的婴儿配方奶粉、即食型（RTF）液态牛奶基婴儿配方奶粉、成人低脂奶粉以及成人高脂高蛋白即饮型营养产品。色氨酸通过在链霉蛋白酶中发现的蛋白水解酶组合从产品基质中的完整蛋白质中释放出来。蛋白水解后，色氨酸通过反相等度高效液相色谱法和荧光检测进行定量。将制备好的样品注入到以甲醇/0.05M磷酸盐缓冲液为流动相的C8高效液相色谱柱上。总体而言，对于色氨酸，重复性平均相对标准偏差（RSD）为2.1%，范围为0.9 - 3.6%RSD，再现性平均RSD为4.2%，范围为3.0 - 9.9%RSD。在分析的14种基质中有13种达到了重复性（SMPRs®）要求，在14种产品基质中有11种达到了再现性SMPRs要求。
