A critical review of chromatographic methods for analyzing haloacetic acids in water: Advances, uncertainties, and prospects

Haloacetic acids (HAAs), which are the second largest group of halogenated disinfection byproducts, raise great analytical challenges because of their hydrophilicity, non-volatility, and acidity. To determine HAAs in drinking water, many pretreatment methods (such as extraction and derivatization) have been proposed since 2000. These methods vary significantly in principles and performance, each carrying inherent analytical errors. This review critically compared typical pretreatment, separation, and detection techniques in terms of advantages and disadvantages, aiming to enable an in-depth and comprehensive understanding of HAAs analysis and help researchers meet analytical requirements. Accordingly, we also identified several analytical error sources less considered before, which may alert later method developers. Finally, we proposed several research prospects, such as analyzing trace amounts of multiple HAAs in their native chemical form, especially for iodoacetic acids at ng/L levels, under mild conditions, e.g., free of reagents, ambient temperature, and neutral pH conditions.