Application of PLS multivariate calibration for the determination of the hydroxyl group content in calcined silica by DRIFTS

A method based on diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was developed for the rapid determination of the hydroxyl group content in calcined silica. Thermogravimetry (TG) was used as a reference method to determine the hydroxyl concentrations. The data pretreatment was performed with orthogonal signal correction (OSC) and it was followed by subsequent partial least squares (PLS) modelling. The calibration model was validated by predicting the hydroxyl content of samples not used in the construction of the models. The OSC‐PLS model was able, with sufficient accuracy, to predict the hydroxyl content of several calcined silicas with different physical properties. Copyright © 2000 John Wiley & Sons, Ltd.