Análise comparativa das técnicas de Fluorescência de Raios-X e Fluorescência UV para a determinação do teor de enxofre em amostras de óleo Diesel

Abstract

In this work, x-ray fluorescence (XRF) and ultraviolet fluorescence (UV) techniques were compared for determining the sulfur content in diesel oil samples, through a statistical evaluation of the data obtained for each technique, for a same set of samples, since the X-ray fluorescence technique can be used for quantitative and qualitative elementary analysis, using short wavelength electromagnetic radiation produced by the deceleration of electrons in the internal orbitals of atoms and fluorescence technique by UV, the sample is excited so as to emit UV radiation at a specific wavelength. Therefore, we applied the T-Student method in addition to other statistical parameters to compare the efficiency of the XRF and UV methodologies. Satisfactory results were observed for determining the sulfur content in diesel oil samples using both techniques. The calibration curves used for the tests showed coefficient of determination (R²) = 0.99795, for ASTM D5453, and, for ASTM D7220, coefficient of determination (R²) = 0.99966 with sulfur concentrations of 103 mg/Kg, 206 mg/Kg,313 mg/Kg, 406 mg/Kg and 508mg/Kg for type S10 B and with sulfur concentrations of 111mg/Kg, 210 mg/Kg, 317 mg/Kg, 405 mg/Kg and 510 mg/Kg for S10 A samples. The actual average concentrations found were: 114.5 mg/Kg, 193.6 mg/Kg, 320.5 mg/Kg, 369.4mg/Kg and 468.5 mg/Kg for the S10 B sample in the UV technique and for the FRX technique it was 107.2mg/Kg, 209.1 mg/Kg, 318.2 mg/Kg, 411.5 mg/Kg and 512.9 mg/Kg. For S10 A samples in the UV technique, the actual average concentrations found were: 110.0 mg/Kg, 198.3 mg/Kg, 296.0 mg/Kg, 371.6 mg/Kg and 437.3 mg/Kg and for FRX 109.2 mg/Kg, 218.9 mg/Kg, 332.3 mg/Kg , 417.5 mg/Kg and 524.4 mg/Kg, all samples were analyzed in triplicates, showing a confidence interval of 95 and 99% satisfactory for both techniques, however the ultraviolet technique proved to be even more accurate in addition to the selectivity is toughness with favorable detection limit.