The Difference of Tibetan Medicine Nanhanhuanshi From Different Producing Areas Based on Multi‐Element and C/O/Sr Stable Isotope

RATIONALE: Tibetan medicine calcite (the traditional Chinese medicine name is "Nanhanshuishi") is a commonly used mineral medicine. However, calcite comes from many places, and the quality of medicine is uneven. Therefore, it is particularly important to develop an accurate and efficient method to identify the origin calcite. METHODS: A total of 32 calcite samples from four different geographical areas were collected from three different provinces in southwest China. The C/O/Sr stable isotope ratios and 45 trace elements were determined using isotope ratio mass spectrometer and ICP-MS. At the same time, the trace elements and isotope information of calcite were analyzed by statistical methods. RESULTS: Sr, and trace elements provided useful information for the identification of calcite from the four regions. Moreover, the application of multivariate statistical approaches, including the CA, PCA, and PLS-DA, to explore the ability of C/O/Sr stable isotopes and trace elements for determining the geographical origins of calcite identified a significant difference (p < 0.05) in the stable isotope ratios from different regions. CONCLUSIONS: PLS-DA has more accurate differentiation due to the supervision of elements. The present findings suggest that the C/O/Sr stable isotopes and trace elements can be potentially applied in the authentication of different geographical origins of calcite.