Development and Validation of Complexometric Methods for the Determination of Cal-Cium and Magnesium in Medicinal Plant Materials (On the Grass Persicaria Maculosa Gray.)

Abstract

The relevance of the study of the mineral composition of plant objects is undoubted. In plant organisms, macro and micronutrients are present in an easily digestible form. The macroelements most accumulated in plants include calcium and magnesium, whose sources are members of the family Polygonaceae Juss, in particular the genus Persicaria Mill. The aim of the work was to develop a technique for quantitative complexometric determination of calcium and magnesium in plant raw materials after the burning procedure and its validation.
 As a result, optimal conditions for the quantitative determination of calcium and magnesium in plant objects were experimentally selected using the example of Persicaria maculosa Gray. mountaineer grass using complexometric titration after ashing and calcination. For the determination of calcium, the optimum pH value is 11–12, the acidic indicator is dark blue – chromium, the optimum pH for magnesium is 8–9, the indicator is pyrocatechol violet. The calcium content in the plant varies from 0.12% to 0.58%, the amount of magnesium is about 0.02%. The relative error of the mean determination with a 95% probability was no more than 1.60% and no more than 1.84% when determining calcium and magnesium, respectively. Studies have shown the validity of the developed methodology for indicators of authenticity, precision (convergence, reproducibility), specificity, linearity.