Simultaneous determination of trace concentrations of aldehydes and carboxylic acids in particulate matter

Our method, in contrast to previous primarily qualitative studies, based on derivatization with an aqueous PFBHA followed by BSTFA derivatization, is less labor-intesive and reduces sample losses caused by an evaporation. The method was tested with a broad range of functionalized compounds (95), including monocarboxylic, dicarboxylic and aromatic acids, ketoacids, hydroxyacids and aldehydes. The developed protocol was applied to wood smoke (WS) and urban air standard reference material 1648b (UA) PM. The observed concentrations of aldehydes were 10-3000 μg/gPM in WS PM and 10-900 μg/gPM in UA PM, while those of acids were 20-1800 μg/gPM in WS PM and 15-1200 μg/gPM in UA PM. The most prominent aldehydes were syringaldehyde and vanillin in WS PM and glyoxal in UA PM. The most abundant acids in both PM samples were short-chain dicarboxylic acids (≤C10). WS PM had a high abundance of hydroxyacids (vanillic and malic acids) as well as ketoacids (glutaric and oxalacetic) while UA PM also featured a high abundance of long-chain monocarboxylic acids (≥C16).