Determination of the strontium isotope ratio by ICP-MS ginseng as a tracer of regional origin

Abstract

This study presents the inductively coupled plasma mass spectrometry (ICP-MS) as a method for tracing the regional origin of ginseng. The results of the analysis of 15 Korean ginsengs from three different regions and of 15 Chinese ginsengs from three different regions reveal that the Sr isotope ratios 87Sr/86Sr of the ginsengs differed according to their origin. For pretreatment, the ginseng samples were dried, and were dissolved through microwave digestion, then were each made to amount to 6ml with 11.9M HCl. Rb was then separated from Sr to enable an interference-free measurement through cation exchange chromatography. Six millilitres of the ginseng sample were injected in the column, and 60ml of 11.9M HCl was passed through the column at a 1mlmin−1 flow rate to separate Rb from Sr. After Rb was eluted completely, 60ml of 5.0M HCl was passed at a 1mlmin−1 flow rate to collect Sr. In the Sr collection step, the first 10ml portion of 30ml eluate was discarded, and the next 10ml portion was taken and was diluted with de-ionized water at a ratio of 1:3, for analysis purposes. The results of the analysis of 30 ginseng samples revealed that the Chinese ginsengs have an 87Sr/86Sr ratio range of 0.672–0.701, and the Korean ginsengs 0.705–0.714. The Korean ginsengs, therefore, have a higher 87Sr/86Sr ratio range than the Chinese ginsengs. Of the Korean ginsengs, 87Sr/86Sr ratio range of ginsengs from Punggi, Geumsan and Hongcheon are about 0.706–0.709, 0.705–0.706, and 0.710–0.714, respectively.