Non-targeted (ultra-)high-resolution mass spectrometry of dissolved organic matter to predict the formation of disinfection byproducts

Dissolved organic matter (DOM) is a complex mixture of organic compounds, which is of significant relevance in the context of drinking water treatment. This importance stems from its well-established role as the primary precursor of potentially harmful disinfection byproducts (DBPs) when subjected to chemical disinfection processes. Characterizing DOM in drinking water is a challenging task due to its inherent heterogeneity and the wide range of organic compounds it contains. Additionally, the composition of DOM can vary based on the source water quality and the specific treatment processes employed. Advanced analytical techniques, such as non-targeted analyses using ultrahigh- or high-resolution mass spectrometry [(U-)HRMS], are improving our understanding of the nature of specific organic compounds present in DOM and their potential to form DBPs. In this review, the most commonly used non-targeted (U-)HRMS approaches for analyzing DOM in raw and treated waters are reported, and their application as a monitoring tool to track changes in DOM and the formation of DBPs in drinking waters is assessed. Moreover, recommendations for achieving a common and comparable DOM fingerprint approach for drinking water among different laboratories and instruments are provided. The non-targeted (U-)HRMS results reviewed here provide DOM indexes and ranges that can assist in tracking the various effects of drinking water treatment processes. Overall, DOM characterization using non-targeted (U-)HRMS is presented as an effective tool for evaluating treatment processes, predicting DBP formation, and the assessment of drinking water quality for human consumption.