Rapid quantification of adulterated Panax notoginseng powder by ultraviolet-visible diffuse reflectance spectroscopy combined with chemometrics

Abstract

• The feasibility of quantification of Panax notoginseng (PN) with its three adulterants by ultraviolet-visible diffuse reflectance spectroscopy is investigated. • PLS serves as the modeling tool and Haaland-Thomas F -test is used for determine the number of latent variables. • To achieve optimal models, several spectral preprocessing and variable selection methods were investigated. As a valuable traditional Chinese medicine (TCM), Panax notoginseng (PN) is often adulterated with similar and much cheaper adulterants, such as rhizoma curcumae (RC), Curcuma longa (CL) and rhizoma alpiniae officinarum (RAO). The feasibility of ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy combined with chemometrics is investigated for rapid quantitative analysis of adulterated PN powder. Partial least squares (PLS) is used for calibration modeling. To avoid over-fitting of PLS, the Haaland-Thomas F-test is introduced to determine the optimal number of latent variables (LVs). For further improving the predictive performance of PLS model, six preprocessing and three variable selection methods are investigated. Results show that correlation coefficients ( R p ) of the optimal models for PN and its three adulterants in prediction set are all above 0.98. Thus, UV-Vis diffuse reflectance spectroscopy combined with chemometrics provides an economic alternative for rapid and non-destructive quantification of adulterated PN samples.