<i>“I’ve seen fire and I’ve seen rain, I’v seen sunny days I thought would never end…”,</i> the lyrics of James Taylor's song (1968) echo like a ghost in the dark days (literally) that struck both California and Colorado last summer. During the height of the Covid-19 pandemic, wildfires swept through the western United States burning over 5 million acres in just two states, and sending ash choking San Francisco and blanketing Denver for weeks. During this time we have sampled ash from these fires in order to identify unknown organic compounds from the partially oxidized woody materials, soil, and plant remains. Climate change has created drier and windy conditions for the western United States, which in conjunction with the prevention of natural fires has created conditions for the perfect firestorm. In order to understand what is present in the water leachable fraction of the ash, we have extracted ash with deionized water and analyzed the leachate directly with ultrahigh performance liquid chromatography followed by quadruple time of flight mass spectrometry. Three acquisition modes (MS1 TOF only, data dependent MS-MS, and data independent MS-MS) were used to identify over 100 different products. Target, suspect, unknown, and unknown-unknowns were identified using these acquisition modes. Furthermore, a new style of library was created, called a “Putative Library”, which is used to rapidly identify (putatively) over 100 compounds in water samples and ash leachates using data independent MS-MS procedures, quadrupole-resolved all ions (Q-RAI). The concept, workflow, and identity of these aromatic acids and their isomers will be discussed in this presentation, as well as their possible environmental impact on water quality.

“Fire and rain”: Accurate mass identification of unknowns from wlidfire ash

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.