Primary speciation analysis of metal trace elements in Radix Scutellariae using inductively coupled plasma-mass spectrometry

Radix Scutellariae from different producing areas were processed by wet digestion, and a total of 28 metal trace elements, whichmay be essential or harmful to human being, were determined using inductively coupled plasma-mass spectrometry (ICP-MS) firstly. The results indicate that the kind of metal elements in Radix Scutellariae from different area were basically the same, but the contents maybe different and the contents of different metal elements change in a wide range with Se 0.1 µg·g-1~Mg 5277 µg·g-1. Furthermore, take the leaching rate as index, the primary speciation analysis of metal trace elements in Radix Scutellariae were performed. The results show that the leaching rates of different metals are different, i.e., the majority are lower than 30%while several are higher than 85%. The higher or lower leaching rates of differentmetal elements show that the metal elements can form complexes with other organic active ingredient in Radix Scutellariae, and the stabilities of the complex is determined by its solubility and the size of the organic ligand. Among the higher soluble metal elements, they are maybe existed as free ions or binding with lower molecular weight and all of them are formed in small particles, they are easier to pass through the filter membrane and easily to be absorbed. The experimental results can provide theoretical basis for decoction of TCM to a certain extent.