Evaluation of multiblock NIR/MIR PLS predictive models to detect adulteration of diesel/biodiesel blends by vegetal oil

This work investigates the potential of using simultaneously near infrared (NIR) and mid infrared (MIR) spectroscopy for the quantification of vegetable oil in diesel/biodiesel blends. The two spectral ranges were used separately with PLS regressions. To combine the two pieces of information, first a concatenated matrix was used and then H-PLS and S-PLS models were constructed. The models were compared in term of prediction errors (RMSEP). The results obtained in NIR spectroscopy were better than the ones obtained with MIR spectroscopy (considering the influence of the pretreatment and of the selected variables range). The multiblock methodology seems to be of great interest in quantitative analysis with the simultaneous use of information from the MIR and NIR spectroscopy.