Avaliação analítica de analisador de combustível comercial no controle de qualidade de etanol e gasolina comum

ANALYTICAL EVALUATION OF COMMERCIAL FUEL ANALYZER IN GASOLINE AND ETHANOL FUEL QUALITY CONTROL. Brazilian news media is full of examples about fuels out of the compliances and needs to control fuel quality. This work proposed an analytical validation of a commercial near infrared photometer (Xerloq, Tech Chrom Analytical Instruments, Brazil) able to identify percentage of ethanol in fuels comparing with NBR standards. Four procedures were selected: analysis of ethanol percentage in gasoline type C samples comparing with standard method ABNT 13992; analysis of ethanol percentage in fuel ethanol samples comparing with standard method ABNT 5992; linearity correlation and selectivity of standard solution analysis. Comparisons between the photometer and standards measurements were to determine the accuracy and precision of the device which presented a little variation from the norm (E_R < 1.3%, s_R < 0.4%). With regard to the test for linearity, Ethanol:water mixtures was analyzed with R-squared larger than 0.999 with RMSEV less than 1%. On selectivity tests, Gasoline:Ethanol:water and Methanol:Ethanol:water mixtures were measured with bias error not exceeding 5% for regulated samples. In conclusion, this fuel analyzer can be used to analyze ethanol content in Brazilian fuels with similar results comparing with classical standard volumetric and glass densimeter analysis and may indicate adulteration gasoline and ethanol samples by anomalous data.

Keywords:
fuel quality; ABNT 5992; ABNT 13992; ethanol analyzer