Enhanced selectivity for acidic contaminants in drinking water: From suspect screening to toxicity prediction

• Published in: Journal of hazardous materials Vol. 448; p. 130906
• Main Authors: Ciccarelli, Davide, Christopher Braddock, D., Surman, Andrew J., Arenas, Blanca Ivonne Vergara, Salal, Tara, Marczylo, Tim, Vineis, Paolo, Barron, Leon P.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.04.2023
• Subjects: Chromatography, Liquid - methods; Disinfectant by-products; Dissolved organic matter; Drinking Water - chemistry; Feature reduction; High-resolution mass spectrometry; Perfluorinated acids; Solid Phase Extraction - methods; Strong anion exchange; Tandem Mass Spectrometry - methods; Water Pollutants, Chemical - chemistry; Disinfectant by-products; Perfluorinated acids; High-resolution mass spectrometry; Dissolved organic matter; Strong anion exchange; Feature reduction
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.130906

A novel analytical workflow for suspect screening of organic acidic contaminants in drinking water is presented, featuring selective extraction by silica-based strong anion-exchange solid-phase extraction, mixed-mode liquid chromatography-high resolution accurate mass spectrometry (LC-HRMS), peak detection, feature reduction and compound identification. The novel use of an ammonium bicarbonate-based elution solvent extended strong anion-exchange solid-phase extraction applicability to LC-HRMS of strong acids. This approach performed with consistently higher recovery and repeatability (88 ± 7 % at 500 ng L-1), improved selectivity and lower matrix interference (mean = 12 %) over a generic mixed-mode weak anion exchange SPE method. In addition, a novel filter for reducing full-scan features from fulvic and humic acids was successfully introduced, reducing workload and potential for false positives. The workflow was then applied to 10 London municipal drinking water samples, revealing the presence of 22 confirmed and 37 tentatively identified substances. Several poorly investigated and potentially harmful compounds were found which included halogenated hydroxy-cyclopentene-diones and dibromomethanesulfonic acid. Some of these compounds have been reported as mutagenic in test systems and thus their presence here requires further investigation. Overall, this approach demonstrated that employing selective extraction improved detection and helped shortlist suspects and potentially toxic chemical contaminants with higher confidence. [Display omitted] •Suspect screening LC-HRMS workflow tailored for trace organic acid contaminants.•NH4HCO3 extends applicability of strong anion exchange solid-phase extraction.•Creation of a novel filter for reduction of dissolved organic matter features.•Dibromomethanesulfonic acid confirmed and quantified in UK drinking water.•New formation pathways for tribromo- and trichloro-hydroxycyclopentenedione proposed.