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 (microNlR) 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 microNlR data to determine the amount of biodiesel in diesel (LODBio = 0.5 wt%; LOQ(Bio) = 1.8 wt%; and RMSEPBio = 1.8 wt%); sulfur in diesel (LODs = 2.4 mg L-1; LOQ(s) = 8.0 mg L-1; and RMSEPs = 13.2 mg L-1); gasoline, ethanol, and methanol in C-type gasoline (LODgas = 0.55 wt %; LOQ(gas) = 1.84 wt%; and RMSEPgas = 0.81 wt%; LODeth = 0.75 wt%; LOQ(eth) = 2.5 wt%; and RMSEPeth = 3.81 wt%; and LODmet = 0.85 wt%; LOQ(met) = 2.84 wt%; and RMSEPmet = 1.80 wt%); and water, methanol, and ethanol in ethanol-hydrated fuel (EHF) (LODH2O = 0.04 wt%; LOQ(H2O) = 1.29 wt%; and RMSEPH2O = 1.05 wt%; LODmet = 0.52 wt%; LOQ(met) = 1.73 wt%; and RMSEPmet = 2.78 wt%; and LODeth = 1.22 wt%; LOQ(eth) = 4.07 wt %; and RMSEPeth = 4.41 wt%). A total of 181 blends were prepared, with biodiesel and sulfur contents ranging from 0 to 100 wt% and 10-500 mg L-1, respectively. For gasoline blends, the gasoline, ethanol, and methanol contents ranged from 0.0 to 75.0 wt%, 25.0-75.0 wt%, and 0.0-50.0 wt%, respectively. In the EHF control, the ethanol, water, and methanol contents ranged from 0.0 to 100.0 wt%, 0.0-50.0 wt%, and 0.0-50.0 wt%, respectively. The proposed method presented high precision and accuracy in all cases, and the results showed that the microNlR technique had excellent performance in fuel quality control.