Fluorescência molecular síncrona associada à calibração multivariada como alternativa expedita na determinação de hidrocarbonetos policíclicos aromáticos em matrizes orgânicas complexas

Abstract

The present work aimed to study polycyclic aromatic hydrocarbons (PAHs) and oxygenated derivatives (OHPAs) in asphalt matrices (CAP) and printing toner. For that, two synchronous molecular fluorescence methodologies associated with multivariate calibration to evaluate 7 PAHs and 3 OHPAs were investigated. The methodologies differed in the choice of solvent used, with the best results being obtained with solvents with different polarities - tetrahydrofuran (THF) and acetonitrile (ACN), aiming for greater application versatility. The THF model presented satisfactory prediction results in artificial samples, in addition to enabling better dissolution of the matrix and its constituents (in the case of CAP). The ACN model presented greater sensitivity, in addition to better data compression capacity, where it was possible to obtain results comparable to the THF model, but with a smaller number of factors (information). Regarding the characteristics of the methods, both presented correlation coefficients above 0.91 for the calibration functions and most of recoveries were between 70 and 130% in the prediction in artificial samples, requiring 20 PCs (THF model) and 13 PCs (ACN model) to achieve these results. When applied to real samples, CAP fumes obtained from a smoke generating device (DEC) were used, due to the great complexity and high organic load of the matrix, however it was still not possible to obtain acceptable accuracy in the quantification of the analytes. Although, it was possible to obtain adequate qualitative results, both regarding the presence of these analytes and their relative abundances in the smoke of 4 CAPs, with the results confirmed by the GC-MS/MS technique. When working with a less complex matrix (printing toner), it was only possible to apply the ACN methodology, which resulted in satisfactory quantitative results, with 81 to 125% recovery when compared to the results obtained by GC-MS/MS. Despite a certain loss in accuracy when compared to more common techniques such as chromatography, the proposed methodologies are considerably faster, simpler, and lower cost. The multivariate tool proved to be suitable as an expeditious alternative for screening samples in relation to analytes.