Jaudzems Gregory G
Nestlé Quality Assurance Center, 6625 Eiterman Rd, Dublin, OH 43017, USA.
J AOAC Int. 2015 Sep-Oct;98(5):1390-4. doi: 10.5740/jaoacint.15-136.
A direct potentiometric method involving titration against a standard volumetric silver nitrate solution using a silver electrode to detect the end point was evaluated for the determination of chloride in infant formula and adult/pediatric nutritional formula. It was assessed for compliance against AOAC Standard Method Performance Requirements (SMPR®) established by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN). A single-laboratory validation (SLV) study was conducted as a first step in the process to validate the method. In this SLV, 17 SPIFAN matrixes representing a range of infant formula and adult nutritional products were evaluated for their chloride content. The analytical range was found to be between 1.4 and 1060 mg/100 g reconstituted product or ready-to-feed (RTF) liquid. The LOQ was estimated as 1.4 mg/100 g. Method repeatability was between 0.03 and 1.60% in the range of 20 to 167 mg/100 g RTF, and intermediate precision was between 0.09 and 2.77% in the same range. Recovery values based on spiking experiments at two different levels of chloride ranged from 99.0 to 103% for 15 different SPIFAN products. Evaluation of trueness was performed on National Institute of Standards and Technology Standard Reference Material 1849a (Infant/Adult Nutritional Formula) and showed 97.2% of the theoretical value, with no bias at the 95% confidence level. Based on the results of the SLV, the method met the SMPR and was approved as a First Action method by the AOAC Expert Review Panel on Infant Formula and Adult Nutritionals on March 17, 2015.
评估了一种直接电位滴定法，该方法通过用银电极滴定标准硝酸银容量溶液来检测终点，用于测定婴儿配方奶粉和成人/儿童营养配方奶粉中的氯化物。根据美国官方分析化学师协会（AOAC）婴儿配方奶粉和成人营养产品利益相关者小组（SPIFAN）制定的AOAC标准方法性能要求（SMPR®）对其进行了评估。作为方法验证过程的第一步，进行了单实验室验证（SLV）研究。在该SLV中，对代表一系列婴儿配方奶粉和成人营养产品的17种SPIFAN基质的氯化物含量进行了评估。发现分析范围为每100克复原产品或即食（RTF）液体中1.4至1060毫克。估计定量限为每100克1.4毫克。在20至167毫克/100克RTF范围内，方法重复性在0.03%至1.60%之间，中间精密度在相同范围内为0.09%至2.77%。基于对15种不同SPIFAN产品在两个不同氯化物水平下加标实验的回收率值在99.0%至103%之间。对美国国家标准与技术研究院标准参考物质1849a（婴儿/成人营养配方奶粉）进行了准确性评估，结果显示为理论值的97.2%，在95%置信水平下无偏差。基于SLV的结果，该方法符合SMPR要求，并于2015年3月17日被AOAC婴儿配方奶粉和成人营养产品专家评审小组批准为首次采用方法。
