DETERMINAÇÃO IN LOCO DO TEOR DE METANOL EM ETANOL POR FTIR E QUIMIOMETRIA PARA COMBATE À ADULTERAÇÃO DE COMBUSTÍVEIS

ON-SITE DETERMINATION OF THE METHANOL CONTENT IN ETHANOL BY FTIR AND CHEMOMETRICS TO COMBAT FUEL ADULTERATION. Based on National Agency of Petroleum, Natural Gas and Biofuels (ANP) Resolution No. 696, the limit of methanol content in ethanol anhydrous fuel and ethanol hydrated fuel is 0.5% v/v. Despite this, unfortunately what has been seen in the field is this rampant adulteration in some places. The adulteration of methanol in ethanol is harmful to society and ends up being carried out due to the lower value of the methanol compared to ethanol. This illegal use can cause high consumption in the automotives and injuries to human health (notably gas station attendants and mechanics), environmental damage and tax evasion. This analysis cannot be determined using the current quality testing equipment determined by ANP, since they are not sufficient for this on-site analysis. Therefore, it was used the Cary 630 Fourier transformed infrared spectroscopy (FTIR) allied to partial least squares (PLS) to quantify methanol in ethanol fuels with: root mean square error of calibration (RMSEC), root mean square error of cross validation (RMSECV) and root mean square error of prediction (RMSEP) values of 0.2% v/v, 0.2% v/v and 0.2% v/v, respectively. The method can be extremely helpful to technical experts to quickly obtain a preliminary result outside the laboratory, in less than ten seconds, allowing a rapid decision by public agency and companies if the methanol content in the sample is outside the acceptable limit.