Use of Direct Aqueous Injection and Solid Phase Extraction Coupled with Hydrophilic Interaction Chromatography to Analyze Haloacetic Acids in Drinking Water Samples

Abstract

In this study, two analytical methods were evaluated to determine haloacetic acids (HAAs) in drinking water samples. Direct aqueous injection (DAI) and solid phase extraction (SPE) were evaluated and determination was performed by liquid chromatography tandem mass spectrometry (LC-MS/MS) with a hydrophilic interaction chromatography (HILIC) analytical column. Limits of quantification (LOQ) were between 10 and 500 µg L-1 by DAI and, considering a 125-fold pre-concentration step, between 0.08 and 2.0 µg L-1 by SPE. Five HAAs exhibited good linear correlation coefficients, accuracy (70-120%) and precision (≤ 20%) using DAI, while accuracy (50-120%) and precision (≤ 20%) were reached for SPE, with the exception of monobromoacetic acid (MBAA), which showed accuracy < 50%. DAI showed to be a simple, fast and promising technique that reduces operators’ exposure and may replace methods that require a derivatization process, reaching LOQs below those established by the regulations for most analytes. SPE using polymeric cartridges and 2 mL of acetonitrile as elution solvent showed to be an interesting alternative for samples with low levels of HAAs. After evaluating the techniques, DAI was successfully employed to determine HAAs in drinking water samples and DCAA was detected in samples in concentrations between 15.3 and 33.6 µg L-1 and DBAA in concentration below 10 µg L-1.