Fast analysis of multiple haloacetic acids and nitrosamines in recycled and environmental waters using liquid chromatography-mass spectrometry with positive–negative switching and multiple reaction monitoring

Abstract

Disinfection by-products, such as haloacetic acids and nitrosamines, are toxic compounds that commonly occur in chemically treated water. They are formed through reactions between chemical disinfectants and both natural and anthropic organic matter. Levels of disinfection by-products in drinking water are regulated worldwide due to their known health effects, making their continued, fast and accurate analysis very important. Monitoring is particularly significant in areas that practise augmentation of potable water with recycled sources such as Namibia and Singapore. Disinfection by-products come in many forms and the analysis of different groups is typically undertaken separately, each requiring different extraction and separation techniques. Both gas chromatography and high-performance liquid chromatography may be used and, in both cases, USA EPA and ISO methods exist in addition to methods published in scientific journals. In this study a new method is presented that utilises liquid chromatography hyphenated triple quadrupole mass spectrometry with positive–negative switching within a single run. This approach allows for the analysis of 11 compounds, (5 haloacetic acids and 6 nitrosamines), within 6 minutes. Limits of detection were 0.05–0.1 parts per billion (μg L⁻¹). The method significantly speeds up the analysis time for disinfection by-products, removes the need for extraction and preconcentration, and may have benefits for the water and environmental industries amongst others.