Analysis of Haloacetic Acids in Drinking Water Using Triple Quadrupole LC/MS/MS (LCMS-8050)

Introduction

Haloacetic acids (HAAs), by-products of water disinfection, are formed from naturally occurring organic and inorganic materials in water which react with the disinfectants chlorine and chloramine. The Japanese Ministry of Health, Labour and Welfare has established criterion values for three of these substances, monochloroacetic acid (MCAA: 0.02 mg/L), dichloroacetic acid (DCAA: 0.04 mg/L), and trichloroacetic acid (TCAA: 0.2 mg/L). The official analytical method for measuring these haloacetic acids utilizes solvent extraction and diazomethane derivatization prior to GC/MS quantitation. In April, 2012, this method was amended to include LC/MS/MS as an additional method for measuring haloacetic acids. These LC/MS methods, which permit analysis of HAAs directly from water samples, offer greater sample throughput by eliminating the solvent extraction and derivatization steps required when using GC/MS. This Application News introduces the use of the LCMS-8050 triple quadrupole mass spectrometer for analysis of these HAAs in accordance with the official LC/MS methodology requirements. In this high speed method, MCAA, DCAA, and TCAA are eluted at 3.1, 3.4, and 5.2 minutes, respectively. Fig. 1 shows an MRM chromatogram of these HAAs each at a concentration of 0.001 mg/L. The calibration curve in Fig. 2 demonstrates linearity from 0.001 to 0.1 mg/L for each substance, and peak area repeatability at 0.001 mg/L (less than 1/10 the criterion value) (n=5), which was less than 3 % (%RSD).

July 18, 2014 GMT