Fluorometric quantification of alkaloids in the homeopathic mother tinctures of Vinca minor L. and Fumaria officinalis L.

Abstract

To assess the toxic potential of the alkaloids, a quantification method is necessary. An ion pair extraction method was used for quantitative fluorometric determination of vincamine, protopine and all contained alkaloids in the mother tinctures of Vinca minor and Fumaria officinalis. The non-fluorescent alkaloids were transformed into an ion pair with sodium-9,10-dimethoxy-anthracene-sulfonate and then fluorometrically determined and quantified in this study. The applicable ion pair was extracted in a suitable organic solvent, where dichloromethane has proven to be beneficial. Conditions for the ion pairing and fluorometric quantification are given. The recovery rate was used to investigate the quality of determinability and the influence of the mother tincture matrix. The method was applied to determine the concentration of protopine in the range 0.1 - 15 μg/ml and of vincamine in the range of 0.5 - 20 μg/ml. The limit of detection was < 0.3 μg/ml, and the limit of quantification < 0.9 μg/ml for both alkaloids.