Differential Analysis of Ginseng Methanol Extracts From Different Origins using FTIR and 2D-COS-IR

Abstract

The quality of ginseng is largely determined by its ginsenoside. However, the high similarity among such extracts poses a considerable challenge to the rapid and differentiation of their origins, which is critical for ensuring product quality. In this study, Fourier transform infrared spectroscopy (FTIR), second-derivative infrared spectroscopy (SD-IR) and two-dimensional correlation infrared spectroscopy (2D-COS-IR) combined with chemometric methods (similarity analysis, dual-index sequence analysis, principal component analysis) were applied to discriminate ginseng methanol extracts from ten origins. FTIR confirms the consistent core saponin structure of all samples but had limited discriminatory ability; SD-IR amplifies subtle static spectral differences through dual-index sequence analysis (DISA); 2D-COS-IR, the most effective technique, achieved differentiation: Synchronous spectra displayed sample-specific auto-peak distributions and intensity variations, reflecting the distinct thermal responses of functional groups from different sources. Asynchronous spectra showed unique cross-peak patterns, and Noda's rules revealed divergent molecular response sequences to thermal perturbation across different samples. The integrated FTIR, SD-IR and 2D-COS-IR strategy enables rapid, non-destructive differentiation analysis of ginseng methanol extracts, providing a reference basis for the differentiation of other similar samples.