Chemometric determination of PAHs in aerosol samples by fluorescence spectroscopy and second-order data analysis algorithms

摘要

The development of a method based on the combination of excitation–emission fluorescence matrices (EEMs) and second-order algorithms is proposed to identify and quantify 10 polycyclic aromatic hydrocarbons (PAHs) in extracts of aerosol samples, a particularly complex sample matrix because of the low amount of PAHs and the numerous fluorescent interferences. Parallel factor analysis, unfolded partial least squares coupled to residual bilinearization (RBL) and multivariate curve resolution – alternating least squares offered satisfactory results for their identification and quantification and were also helpful for the optimization of the extraction procedure for these substances by means of analysis of a standard reference material. Multivariate curve resolution – alternating least squares and parallel factor analysis combined with EEM proved to be fast and cheap analysis methods that are able to do semiquantitative monitoring of PAHs patterns in the inhalable and respirable fractions of atmospheric aerosols, important features for routine environmental monitoring. Accurate quantifications could also be achieved when the strategy of standard addition method was used. Unfolded partial least squares/RBL achieved slightly better quantitative results when sample matrices were moderately complex; in aerosol sample analysis, the selection of number of RBL contributions turned particularly difficult— because of the lack of information on the sample composition—and the time-consuming application of the method did not suggest its use for routine environmental monitoring. Finally, results of EEM with second-order methods in agreement with gas chromatography-mass spectrometry analysis of ambient air samples proved the suitability of the methodology proposed because of the sensitivity of fluorescencemeasurements and the lower analytical cost and fast computation time compared with standard analytical procedures.