[Validation Study on a Rapid and Low-priced Method for Determination of Chloroacetic Acids in Mineral Water Products]

An LC-MS/MS method for the simultaneous determination of chloroacetic acid, dichloroacetic acid and trichloroacetic acid (chloroacetic acids) in mineral water (MW) products was developed by modifying the Japanese official method to determine chloroacetic acids. To prevent ion suppression or enhancement caused by sample matrix in LC-MS/MS analysis, the Japanese official method comprises the cleanup step of analytes using cation exchange resin column. The step is time-consuming and costly, and thus the modified method adopted small-volume injection instead of it to prevent matrix effects on ionization, which enabled rapid analysis at low cost. A validation study was performed on the method using MW products which vary in the degree of hardness and contents of carbonate. The trueness, repeatability and reproducibility of the method were estimated to be within the ranges of 95.3 to 104.3%, 1.1 to 2.9% and 2.4 to 6.4%, respectively. The values of every performance parameter met the criteria in the guidelines announced by the Ministry of Health, Labour and Welfare of Japan. A recovery study was performed on 30 kinds of MW products to examine the applicability of the method, and the recovery rate of all target substances ranged from 91 to 108%. Therefore, the modified method is considered to be suitable for the determination of chloroacetic acids in MW products.