Profiling metals in Cordyceps sinensis by using inductively coupled plasma mass spectrometry

Abstract

Cordyceps sinensis (C. sinensis) is a natural product that has diverse nutritional and medicinal values. Since the availability of natural C. sinensis becomes limited its authentication and quality control is of high significance. Herein we report on profiling of metals in C. sinensis by using inductively coupled plasma mass spectrometry (ICP-MS). The analysis reveals that C. sinensis contains a wide array of essential elements, including P, Mg, Zn, Cu, Fe, etc. Toxic metals detected are Cd, Pb, and As. In all five samples analyzed Pb contents are below 2.0 ppm. Arsenic level in C. sinensis caterpillar is significantly higher than that in its mycelium and varies from 3.0 to 32 ppm likely due to soil contamination. It's for the first time demonstrated in this work that clustering analysis on the proposed metal profiles consisting of 24 elements is very useful to identify "abnormal" C. sinensis samples, thus adding another dimension to the effective means for authentication and quality assessment of this highly demanded previous natural product.

Keywords: Clustering analysis; Cordyceps sinensis; ICP-MS; Metal Profile; Natural products; Toxic metals.

Figure 1

Dendrogram and heatmap obtained by HCL hierarchical clustering analysis of 24 metal concentrations in 10 samples. The data are separated into two groups (the ones with ppb unit on the left and the ones with ppm unit on the right) with the order of the columns based on the averaged contents of each metal. The heatmap is based on global Z-scoring transformation of the metal contents.