Abstract
We developed a liquid chromatography/mass spectrometry (LC/MS) or tandem mass spectrometry (LC/MS/MS) analysis method for the simultaneous determination of six anions (bromate, chlorate, chlorite, perchlorate, nitrate, and nitrite) in drinking water. Furthermore, we conducted a validation test along with 15 organizations to confirm that the analytical method developed in the present study is applicable to various types of drinking water and instruments. Recovery tests of the six anions spiked into drinking water were performed to evaluate the linearity of calibration curves, selectivity, accuracy (recovery) , repeatability, and intermediate precision of these anions. Regarding four anions (bromate, chlorate, chlorite, and perchlorate) , the accuracy, repeatability, and intermediate precision obtained by the recovery tests satisfied the criteria in the guideline for the validation of the testing method for drinking water provided by the Ministry of Health, Labour and Welfare, Japan. Therefore, we concluded that the analytical method developed in the present study is valid for the analysis of these four anions in drinking water. However, ethylenediamine must be used for the dechlorination of water samples because degradation of chlorite was observed by using sodium thiosulfate. In addition, proper ranges of calibration curves should be selected for the determination of these anions because the range of the linearity of calibration curves differed depending on the anion.
