Fast quality assessment and origin identification of Gentianae Macrophyllae Radix using fourier transform infrared photoacoustic spectroscopy coupled with chemometrics

Abstract

This study explores the application of Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) combined with chemometric analysis for rapid quality assessment and origin species verification of Gentianae Macrophyllae Radix (Qinjiao). Qinjiao, a traditional Chinese medicinal herb, faces significant challenges in quality control due to frequent adulteration and substitution. In this study, 195 Qinjiao samples were analyzed using FTIR-PAS, and chemometric techniques were employed for both classification and regression analysis. The results demonstrate that FTIR-PAS, integrated with chemometric methods, effectively differentiates Qinjiao samples by species. The combination of Detrending (DT) preprocessing and a K-Nearest Neighbors (KNN) classification model achieved an accuracy of 97.4 % in species identification. For quantitative analysis, Savitzky-Golay (SG) smoothing was the optimal preprocessing method for gentiopicroside, while DT was best for loganic acid, and no preprocessing was necessary for roburic acid. Additionally, the Competitive Adaptive Reweighted Sampling (CARS) algorithm, combined with models such as XGBoost and Random Forest (RF), significantly improved the prediction accuracy of key active components, with the highest $R_P^2$ reaching 0.84. This research underscores the potential of FTIR-PAS as a rapid, non-destructive approach for the quality assessment and authentication of traditional Chinese medicinal materials.