Abstract
Coptis Rhizome is known to have a relatively high heavy metal content, and in Japanese Pharmacopoeia Supplement Two of the 16th edition, the Heavy Metal Limit Test is added for the purity test of Coptis Rhizome and Powdered Coptis Rhizome. In this Heavy Metal Limit Test, it states that when decision is difficult by the conventional colorimetric method, one should perform lead analysis by flame type Atomic absorption spectrophotometry (ASS) using the colorimetric test solution. However, the concentration of this colorimetric test solution is sometimes insufficient for the AAS test solution, so a new preparation method for the AAS test solution was investigated. The solvent extraction method, dry ashing method, and dry ashing with sulfuric acid method were examined, and the lead recovery rates of all three methods were 70% or more. Among these, the dry ashing method had the largest lead content amounts and lead recovery rate, and was also safe and easy.
As a result of lead validation of analytical procedures by AAS using the dry ashing method, no problem was identified in terms of linearity, detection limit, or quantitation limit. In addition, a lead recovery test using Coptis Rhizome, Orengedokuto Extract, which is a mixture of Coptis Rhizome, and Saikokeishito Extract, in which a slightly higher lead content in the actual condition survey was confirmed, was performed; The lead recovery rate was 70% or more at ashing temperatures of 450-550°C. Furthermore for cadmium, as a result of validation of the analytical procedures by AAS using the dry ashing method, no issues were identified in terms of linearity, detection limit, or quantitation limit. In addition, in a cadmium recovery test using Shoseiryuto Extract, which was confirmed to have a slightly higher cadmium content in the actual condition survey, it was confirmed that the cadmium recovery rate was 70% or more at an ashing temperature of 450°C. From the above, by using the dry ashing method, lead analysis of Coptis Rhizome, Orengedokuto Extract, and Saikokeishito Extract, and cadmium analysis of Shoseiryuto Extract by AAS have become possible.
