Chemical tracers for Wildfires–Analysis of runoff surface Water by LC/Q-TOF-MS

• Published in: Chemosphere (Oxford) Vol. 339; p. 139747
• Main Authors: Ferrer, Imma, Thurman, E. Michael
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2023
• Subjects: Blackwater; Liquid chromatography; Mass spectrometry; Runoff surface water; Time-of-flight; Wildfire; Wildfire; Blackwater; Liquid chromatography; Runoff surface water; Mass spectrometry; Time-of-flight
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.139747

A quantitative methodology using high resolution mass spectrometry was developed for the identification of organic compounds derived from wildfires in surface water samples. The methodology involves the use of solid-phase extraction (SPE) followed by detection using liquid chromatography-quadrupole time of flight-mass spectrometry (LC/Q-TOF-MS) for a group of fourteen chemical compounds (pyridine, benzene, naphthalene and biphenyl polycarboxylic acids). All compounds were successfully separated chromatographically using a reversed phase column and they were identified by accurate mass using the deprotonated species and their main fragment ions. The method produced excellent accuracies (>95%) and precisions (3–10%) for all the compounds studied. This methodology was successfully applied to the identification of fourteen compounds in runoff surface waters impacted by wildfires in Colorado in 2020. Concentrations of individual compounds ranging from 0.1 to 59.5 μg/L were found in wildfire impacted waters, with totals of ∼200 μg/L, thus showing these compounds as chemical tracers of wildfire events at significantly high concentrations. In addition, non-target analysis using chromatography patterns and mass spectrometry identification by MS-MS revealed other polycarboxylic acid isomers were also present in runoff surface water samples. [Display omitted] •Quantitative methodology for 14 organic acids in wildfire-impacted surface waters.•Compounds found in surface waters are chemical tracers for wildfires.•Concentrations in runoff surface (blackwaters) varied from 0.1 to 59.5 μg/L.•Non-target analyses revealed a new set of naphthalene carboxylic acid isomers.