Portable near infrared spectroscopy applied to fuel quality control

Fuel quality control has gained interest in many countries owing to the potential damage of low-quality fuel to engines, the environment, and economy. Thus, the application of analytical techniques to verify quality control of fuels has become crucial. The portable micro-spectrometer in the near infrared region (microNIR) has gained credibility as a successful analytical technique in several quality control sectors. The possibility of real-time analysis using a nondestructive and reliable method is the main advantage of this methodology. In this work, chemometric models (PLS) were developed using microNIR data to determine the amount of biodiesel in diesel (LOD_Bio = 0.5wt%; LOQ_Bio = 1.8wt%; and RMSEP_Bio = 1.8wt%); sulfur in diesel (LOD_S = 2.4mgL^-1; LOQ_S = 8.0mgL^-1; and RMSEP_S = 13.2mgL^-1); gasoline, ethanol, and methanol in C-type gasoline (LOD_gas = 0.55wt%; LOQ_gas = 1.84wt%; and RMSEP_gas = 0.81wt%; LOD_eth = 0.75wt%; LOQ_eth = 2.5wt%; and RMSEP_eth = 3.81wt%; and LOD_met = 0.85wt%; LOQ_met = 2.84wt%; and RMSEP_met = 1.80wt%); and water, methanol, and ethanol in ethanol-hydrated fuel (EHF) (LOD_H2O = 0.04wt%; LOQ_H2O = 1.29wt%; and RMSEP_H2O = 1.05wt%; LOD_met = 0.52wt%; LOQ_met = 1.73wt%; and RMSEP_met = 2.78wt%; and LOD_eth = 1.22wt%; LOQ_eth = 4.07wt%; and RMSEP_eth = 4.41wt%). A total of 181 blends were prepared, with biodiesel and sulfur contents ranging from 0 to 100wt% and 10-500mgL^-1, respectively. For gasoline blends, the gasoline, ethanol, and methanol contents ranged from 0.0 to 75.0wt%, 25.0-75.0wt%, and 0.0-50.0wt%, respectively. In the EHF control, the ethanol, water, and methanol contents ranged from 0.0 to 100.0wt%, 0.0-50.0wt%, and 0.0-50.0wt%, respectively. The proposed method presented high precision and accuracy in all cases, and the results showed that the microNIR technique had excellent performance in fuel quality control.