Combination of stable isotopes and multi-elements analysis with chemometric for determining the geographical origins of Rhizoma Coptidis

Abstract

Rhizoma Coptidis is a valuable medicine food homology plant, whose geographic origin is a topic of interest to both consumers and producers since the geographic origin determines its prices and efficacy. A novel method for discriminating the geographic origins of Rhizoma Coptidis was established based on stable isotopes and multi-elements analysis combined with chemometric. Then, 4 light stable isotope ratios and 32 inorganic elements of 103 samples from six regions were determined. The results showed that the isotopes ratios and multi-elements contents were significantly different among Rhizoma Coptidis from six regions. Al, Sn, Mg, δ15N and δ13C (VIP > 1.5) were considered as the most powerful differentiation markers for discriminating the geographical origins. In addition, by linear discriminant analysis (LDA) and orthogonal partial least squares discriminant analysis (OPLS-DA), all samples were successfully classified with 100% accuracy. Based on the built predictive model, the origin of unknown samples were successfully predicted with 100% accuracy. The parameters of the models R2X, R2Y and Q2 were 0.999, 0.900 and 0.854, respectively. Therefore, the stable isotopes and multi-elements analysis combined with chemometric tools can be successfully used to discriminate the geographic origins of Rhizoma Coptidis.