Determination of ten haloacetic acids in water using gas chromatography-triple quadrupole mass spectrometry

Abstract

A sensitive detection method for ten haloacetic acids (HAAs) in drinking water and wastewater has been developed based on liquid–liquid extraction (LLE) followed by acidic methanol derivatization and gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS). Precursor ions and product ions of the ten HAA esters were identified based on the mass spectra of the GC-QqQ-MS/MS; separation chromatograms for these analytes have been established for water samples of complex matrices. The ratio of acidic methanol to MTBE extract of the HAAs appeared to have profound effects on the HAAs methylation process and higher ratios were found to favor the detection of these analytes. The linear calibration range extended from 0.5 up to 100 μg L⁻¹ (r² = 0.9952–0.9998, n = 8), and limits of detection (LODs) were between 0.012 and 0.079 μg L⁻¹ for all the ten HAAs. The intra-day and inter-day relative standard deviations (RSDs) were in the range of 1.02–6.86% and 1.58–8.16%, respectively. The method was validated by the analysis of surface water, groundwater and wastewater effluent samples spiked with 2.5 and 25 μg L⁻¹ individual HAAs, with the relative analyte recoveries being in the ranges of 90.3–100.2%, 90.5–107.5% and 76.9–101.7%, for the three kinds of water samples respectively.