Draher Jonathan, White Norman
Abbott Nutrition, 3300 Stelzer Rd, Building RP4-3, Columbus, OH 43219.
J AOAC Int. 2018 May 1;101(3):824-830. doi: 10.5740/jaoacint.17-0257. Epub 2017 Sep 19.
A method for tryptophan (Trp) analysis designed to comply with AOAC Standard Method Performance Requirement 2014.013 is described. Unlike AOAC 988.15, which uses alkaline hydrolysis, this method uses enzymatic hydrolysis to release the Trp from the intact protein. The method achieves an LOQ of 0.18 mg/100 g Trp on a ready-to-feed basis with mean recoveries ranging from 93.8 to 104.9%. Repeatability ranged from 0.2 to 5.0%. Intermediate precision ranged from 1.0 to 6.9%. The analytical range was determined to be 0.18-300 mg/100 g, with linearity over eight calibration standard levels giving an average deviation from theoretical levels of 0.3%. No single calibration point had a deviation of >5.0%. Two standard reference materials (SRMs 1849a and 927e) were analyzed, and the average deviation from the certified value was 98.5% for SRM 1849a and 101.2% for SRM 927e. Sample preparation is very similar to existing methods in terms of time and complexity. The use of an internal standard reduces laboratory error and allows for reproducible results.
本文描述了一种符合美国官方分析化学师协会（AOAC）标准方法性能要求2014.013的色氨酸（Trp）分析方法。与使用碱性水解的AOAC 988.15不同，该方法采用酶促水解从完整蛋白质中释放色氨酸。该方法在即食基础上实现了0.18 mg/100 g色氨酸的定量限，平均回收率在93.8%至104.9%之间。重复性范围为0.2%至5.0%。中间精密度范围为1.0%至6.9%。分析范围确定为0.18 - 300 mg/100 g，在八个校准标准水平上具有线性，与理论水平的平均偏差为0.3%。没有单个校准点的偏差大于5.0%。分析了两种标准参考物质（SRM 1849a和927e），SRM 1849a与认证值的平均偏差为98.5%，SRM 927e为101.2%。在时间和复杂性方面，样品制备与现有方法非常相似。使用内标可减少实验室误差并获得可重复的结果。
