Validation and application of a GC-MS method for the determination of haloacetic acids in drinking water

Abstract

Usually, water treatment plants employ chlorine or sodium hypochlorite during the disinfection process, ensuring that there are not any pathogenic microorganisms in water. However, chlorine might react with natural organic matter and lead to formation of potentially carcinogenic by-products regarding human health, such as haloacetic acids (HAAs). Several countries regulate the levels of these acids in drinking water. Therefore, their concentrations must be monitored with the greatest accuracy as possible. In order to achieve this goal, a method through gas chromatography coupled with mass spectrometry (GC-MS) was validated and applied to the determination of HAAs in samples of water destined to the public water service provision from the city of Maringá, Paraná State, Brazil. Measurements between two periods have close recovery values, indicating that the method has good accuracy during the same day. The limits of detection (LOD) and quantification (LOQ) were satisfactory, with LOD 0.42 μg L-1 and LOQ 1.40 μg L-1 for dichloro-acetic acid (DCAA) analysis. Recovery values obtained for the nine haloace-tics acids (HAA9) corresponded to 69.9-107.3 % for samples. The repeatability performed for two periods presented close relative standard deviation (RSD) values, indicating that the method has good accuracy during the same day.

Keywords

• disinfection by-products
• gas chromatography
• mass spectrometry
• merit figures