Kinetic determination of lysine in pharmaceutical sample

Abstract

Akinetic method for the determination of micro quantities of the amino acid lysine (Lys) is described in this paper. The catalytic activity of cobalt in the reaction of the oxidation of purpurin (1,2,4-trihydroxyanthraquinone PP) by hydrogen peroxide in alkaline buffer solution decreases in the presence of micro quantities of lysine, because of the formation of a complex.1,2 The experimental conditions for the successful determination of lysine were optimized. The relative error ranges from 7.7 to 1.9% in the concentration range from 0.118 to 23.520μg cm-3. The detection limit is 0.023μg cm-3. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions and amino acids on the reaction rate were determined in order to assess the selectivity of the method. The method was applied to the determination of lysine in a pharmaceutical sample Riborn-P (Medecon–Belgrade).

Keywords

• kinetic method
• lysine
• purpurin oxidation
• pharmaceutical sample.