Introduction of a simple and effective analytical method for haloacetic acids in drinking water by reverse phase LC-MS/MS Polly Grundy 1 , Peter Jarvis 1 , Bruce Jefferson 1 , John Haley 2 and Emma Goslan 1 1 Cranfield University, UK, 2 UK Water Industry Research Ltd. (UKWIR), UK For many years chlorination has been a key tool of the drinking water industry due to its ability to inactivate pathogens and provide a residual level of disinfectant in the distribution system. However, in the 1970’s it was determined that chlorine can interact with the organic matter present in water to create disinfection by-products (DBPs), some of which are potentially toxic and harmful to human health. The most widely tested and regulated of these are trihalomethanes, but concern is growing about another class of disinfection by-products, the haloacetic acids (HAAs). These are currently under consideration for regulation in the UK, and five of them are already monitored in the US and elsewhere. Furthermore, it is likely that future regulation will include the brominated as well as the chlorinated HAAs due to the higher toxicity of the brominated analogues. The demand therefore exists for a robust and effective analytical method to include all nine of the chlorinated and brominated haloacetic acids (HAA9) in potable water. Historically, HAAs have been analysed by methylation and GC-ECD, but this method is time consuming and entails complex and unreliable derivatisation followed by non-specific ECD detection. As an alternative, this poster presents a simple and accurate method for the direct analysis of HAAs in drinking water by reverse phase liquid chromatography mass spectrometry (LC-MS/MS) 1 . This option has tended to be overlooked due to the difficulties associated with the chromatography of such small, polar molecules and the additional complication presented by the varied and overlapping masses of the compounds in the mass spectrometer. However, the method presented here overcomes these issues and has been validated to ISO 17025 standard in a variety of drinking water matrices with good performance (sensitivity <0.8µg/l, precision <7% and bias <10%). Further demonstration in real tap water samples and comparison to the existing GC-ECD method determined that the LC-MS/MS method was quicker, easier, more accurate and more robust. A protocol is also proposed for method implementation which will enable the problems around chromatography and overlapping mass transitions to be overcome. It is intended that this simple and accurate method can be widely adopted, enabling the water industry to respond efficiently to the likely enhanced regulatory requirements for HAAs. This positive impact on laboratory analytical capability will enable increased understanding of the prevalence of HAA9 in drinking water and therefore the risk they may present. References 1. Grundy, P. et al. (2023). Introduction of a simple and effective analytical method for haloacetic acids (HAAs) in drinking water by reverse phase liquid chromatography mass spectrometry (LC-MS/MS). [Submitted for publication].
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© The Author(s), 2023
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