Optimized procedure for the determination of alkylamines in airborne particulate matter of anthropized areas

Abstract

Abstract. Due to their role in the formation of secondary aerosol, the concentrations of the most abundant aliphatic amines (methylamine (MA), dimethylamine (DMA), ethylamine (EA), diethylamine (DEA), propylamine (PA), and buthylamine) present in the aerosol of a very anthropized area were measured by an optimized analytical procedure. PM10 samples were collected in the tannery district of Vicenza (in the Po Valley, northern Italy) in autumn 2020. Alkylamines were extracted in water and converted to carbamates through derivatization with Fmoc-OSu for subsequent determination by UHPLC with fluorescence detection. The procedure has been optimized and validated obtaining very satisfactory analytical performances: LODs were in the range of 0.09–0.26 ng/m3, average uncertainty of 3.4 % and recoveries of 95–101 %. The mean total concentration of the 6 amines measured in this study was 37 ± 17 ng/m3, with DMA making the largest contribution. The proposed procedure may contribute to a better characterization of the local aerosol. In our preliminary investigation, the Pearson’s correlation test showed that amines correlate strongly with each other and with secondary inorganic ions (NH4+, NO3- and SO42-), confirming that they compete with ammonia in the acid-base atmospheric processes that lead to the formation of nitrate and sulphate particles. The developed method allows to gather critical information about the load of aliphatic amines in PM to gain more insights into the sources and fate of these chemicals in the atmosphere.