Analysis of Rare Earth Elements in Sophora japonica L by Inductively Coupled Plasma Mass Spectrometry

A method for the determination of 15 Rare earth elements (REEs) in Sophora japonica L by inductively coupled plasma mass spectrometry (ICP-MS) was developed. The polyatomic interferences were investigated. Appropriate selection of the detection isotopes made it possible to avoid some interferences. Due to the low availability of most REEs in biological samples, most of the interferences were negligible and only interferences of 135Ba16O+ with 151Eu+, 141Pr16O+ with 157Gd and 143Nd16O+ with 159Tb+ were corrected. Interferences correction was validated by comparing Eu, Gd and Tb contents in GBW 07605 tea standard reference material with and without interference subtraction. The method was applied to the analysis of REEs in flower buds, flowers, leaves, branches and ripe fruits of Sophora japonica L and the distribution of REEs in Sophora japonica L was explored. The results showed large differences in the amounts of different REEs in the same sample. It was found that the concentration of Ce was the highest and that of Lu was the lowest. The REEs contents of Sophora japonica L was found to generally vary in the order ripe fruits< branches< flower buds< flower< leaves, providing valuable data for understanding the effects of REEs on the efficacy of Sophora japonica L related herbal medicine as well as the toxicological and environmental effects for REEs application.

QIANG SHI