[Classification of licorice based on inorganic elements characteristics].

The present study focused on the ecological characteristics of medicinal plants Glycyrrhiza uralensis from two typical ecological environments with two different growth patterns respectively. The authors detected the contents of 16 kinds of inorganic elements in 24 licorice samples with two different producing areas (i. e. Gansu and Inner-Mongolia) and growth patterns (i. e., wild species and the cultivated), using the methods of ICP-MS and ICP-AES after microwave-assisted digestion. With the systematic analytic methods, including the analysis of total element distribution, Q-type cluster analysis of the characteristic elements, and the comparison of element and the ratio of two elements among the samples one by one, the authors constructed the inorganic element fingerprint chromatogram of G. uralensis based on the contents of the 16 inorganic elements (K, Ca, Na, Mg, P, Ca, Cr, Mn, Fe, S, Ni, Cu, Zn, Sr, Mo and Sn). Based on the characteristic elements selected by principal component analysis, the result of Q-type cluster analysis showed consistency with the growth pattern of licorice. By comparing the differences of the inorganic elements in different samples, the authors discovered that the combination of elements Mo and Sr not only provides the bases for the growth pattern of licorice, but also can be used as a diagnostic criteria for the division of its producing area. This study also indicated that the content ratios of Na : P and K : Ca can also provide reliable references for the assessment of different production patterns. It gives insight into the differences in the inorganic element of licorice with different producing area and production pattern treatments. In conclusion, the method we founded here turned out to be intuitive, informative, and highly accurate, and can be used to reveal the characteristic of inoganic elements in medicinal plant.