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.