加标回收在水质分析中的应用及回收率计算方法

阐述了水质分析中加标回收分析的方法步骤、条件控制及计算方法。当加标体积影响试样在加标水样中的浓度时,直接使用回收率理论计算公式的计算值,均较其真实的回收率偏低,且其偏低值随加标体积的增加而增大。根据加标回收分析的定义,分别以加标前后被测组分质量浓度(mg/L)的变化或含量(μg)的变化为依据,导出两个计算加标回收率的实用公式。采用该公式,加标体积可以不受严格控制,其计算结果与真实的回收率一致,适用于日常水质分析工作。

Application of Standard Addition in Water Quality Analysis and Calculation Methods for Recovery Rates

The application of recovery test in water quality analysis and calculation methods of recovery rates were introduced.The results of recovery rates calculated from the theoretical calculation formula usually exhibit the lower values than the true recovery rates when the analyte concentration varies due to the solution volume variation from standard addition,and the larger the addition volume,the bigger the bias.According to the definition of recovery test,two improved formulas were derived based on the differences of concentrations (mg/L) and content (μg) before and after standard addition.The results show that the recovery rates from the two improved formulas are in accordance with the true recovery rates and the methods are suitable for routine water quality analysis.