Optimization and validation of a liquid chromatography method with fluorescence detection for the determination of amines in fine atmospheric particulate matter

Abstract

Primary amines are pollutants present in the atmosphere in gaseous form or as particulate matter, emitted mainly by the industrial sector, vehicles, and biomass burning. There is concern about the concentration of amines present in the atmosphere, as the consequences of long-term exposure cannot be predicted. The objective of the present study is the optimization and subsequent validation of a method for determining amines in fine atmospheric particulate matter, using liquid chromatography and fluorescence detection. The optimization of the derivatization process was carried out through a 2² factorial design to improve the sensitivity of the method, determining that lower concentrations of the reagents o-phthaldialdehyde and 2-mercaptoethanol result in a more pronounced analytical signal. The optimization of the chromatographic method allowed the separation of four primary amines within 20 minutes of run time using solvents such as sodium acetate, methanol and tetrahydrofuran. The method validation showed good performance according to the results for selectivity and linearity, with detection limits of 0.121 to 0.284 ng m-³ and quantification of 0.398 to 0.938 ng m-³. The precision (>5%) and recoveries (82 to 117%) of the method are within recommended values. Therefore, the optimized method for determining amines allowed the application of the method to real samples of atmospheric amines, obtaining concentrations in Brazil comparable to other regions around the world.