Santos, Luciene da SilvaCâmara, Anne Beatriz Figueira2023-12-202023-12-202023-09-21CÂMARA, Anne Beatriz Figueira. Development of analytical methodologies based on advanced chemometric tools coupled with spectroscopic techniques for screening and quantifying fossil fuel adulteration. Orientadora: Dra. Luciene da Silva Santos. 2023. 175f. Tese (Doutorado em Química) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2023.https://repositorio.ufrn.br/handle/123456789/56568Fuel adulteration is an illegal practice that involves the process of mixing other compounds with traditional fuels, using lower-quality and cheaper substances, with the aim of increasing the fuel volume and gaining illegal profits. This illegal practice has far-reaching implications, including environmental pollution, engine damage, and health risks. Typically, fraudsters employ non-standard substances that exhibit similar properties and miscibility with fuels, such as kerosene, and residual vegetable oils, making their detection challenging using conventional physicochemical methods employed in the market. In light of these challenges, this research aims to develop advanced analytical methodologies utilizing cutting-edge chemometric tools. By leveraging these techniques, we seek to enhance the screening and quantification of fuel adulteration, enabling more accurate and efficient identification of tax-exempt substances in petroleum derivatives. The outcomes of this study will contribute to combating this pervasive issue and safeguarding the environment, engines, public health, and government revenue. For this, 60 samples of diesel and 98 samples of jet fuel (JET-A1) were applied to simulate the adulteration process with kerosene solvent (KS) for the application of chemometric models coupled with spectroscopic techniques. The classification algorithms enabled classifying the blends according to the IR absorption bands assigned to oxidation products, such as phenols and carboxylic acid, with high accuracy and 100% sensitivity and specificity for both diesel and JET-A1. MCR-ALS and PLS regression were able to detect and quantify KS in the fuels with high accuracy (RMSEP<1.64%; R2>0.995). MCR-ALS with area constraint and PARAFAC combined with excitation-emission matrix (EEM) fluorescence spectroscopy allowed the quantification of JET-A1. Furthermore, both models also quantified the content of KS with high accuracy (RMSEP < 5.36%). The MCR-ALS model stood out for recovering the spectral profile of the adulterants by segregating them from the fuel spectra. In addition, the developed methodology had an overall performance superior to the traditional physicochemical methods used to screen the adulteration, showing its potential for future application for in loco fuel quality control.Acesso AbertoChemistryScreening fuel adulterationMCR-ALSPARAFACFT-MIR and FT-NIRFluorescence SpectroscopydoctoralThesisCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA