ZINC QUANTIFICATION IN SELECTED PHARMACEUTICAL PRODUCTS BY TWO ANALYTICAL METHODS

Abstract

The aim of this study was to develop two methods that can be used to determine the concentrations of zinc in some pharmaceutical formulations. The first proposed method follows the formation of a red complex between dithizone and zinc which can be spectrophotometrically determined at 516 nm. The second method is based on the detection of zinc through atomic absorption spectrometry, at 213.857 nm, after wet digestion of the samples. The wet ashing method was performed using a mixture of concentrated nitric acid and 30 % hydrogen peroxide (8:2). Both methods were evaluated in terms of linearity, precision (repeatability and intermediate precision), recovery, limit of detection and limit of quantification. The obtained RSD values for the analyzed performance parameters were smaller than the maximum limits recommended by the international standards, therefore the proposed methods can be successfully applied for the determination of zinc in pharmaceutical formulations.