Quantitative analysis of ternary isomer mixtures of saccharide by terahertz time domain spectroscopy combined with chemometrics

•The features of Infrared and THz spectra of the isomers were critically discussed.•THz spectra were used for quantitatively analysis of ternary isomer mixtures.•Linear and nonlinear methods were compared for THz spectra analysis.•Pretreatment methods improved the prediction results of THz spectra model.