Multivariate analysis of quaternary carbamazepine-saccharin mixtures by X-ray diffraction and infrared spectroscopy

► Qualitative and quantitative analysis is performed on quaternary mixtures. ► A novel method is applied for quantitative analysis of X-ray diffraction and IR spectra. ► SNIP was applied for the first time to preprocess IR spectra. ► The Rietveld method supplies the most accurate quantification for X-ray diffraction. ► Partial least squares supply the best quantification for infrared spectroscopy.