Midinfrared Spectroscopy and Partial Least-Squares Model as an Analytical Method for Biodiesel and Glycerol Monitoring

Abstract

This work reports the application of mid-infrared (MIR) spectroscopy and partial least-squares (PLS) model as an analytical method for the quality control of biodiesel production and glycerine treatment. The analytical techniques employed to control biodiesel production are expensive and laborious. On the other hand, the infrared spectroscopy technique has low cost when compared with conventional techniques, simple operation, and low waste generation, which makes it attractive when coupled with multivariate calibration models, such as PLS, as it constitutes a nondestructive analytical method for in-line monitoring biodiesel production reaction. In this work, spectral data were generated by MIR spectroscopy with attenuated total reflectance accessory, which allows a direct analysis. Therefore, for quantification of biodiesel samples, PLS was employed to model MIR spectroscopy data. The evaluated parameters were expressed in terms of acidity, phosphorus, monoacylglycerol, diacylglycerol, triacylglycerol,, water, glycerol, and ash contents.