ICP-MS Determination of Rare Earth Elements in Ginseng

Distribution of 15 rare earth elements (RE′s) in roots, stems and leaves of ginseng collected in different years and in different months of a year was studied by ICP-MS. The sample was digested with HNO3 and H2O2 in a microwave digestor, and the solution obtained was used for the determination of the RE′s (i.e., 89Y, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 151Eu, 157Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb and 175Lu) with Re and Rh added as internal standards. Detection limits (3S/N) for the 15 RE′s were found in the range from 0.24 to 2.46 μg·kg-1. It was found that the contents of RE′s were highest in leaves, middle in roots and least in stems, and that the contents of RE′s in roots tended to accumulate with years of growing.