Development and evaluation of a kinetic-spectrophotometric method for determination of arginine

A kinetic method for the determination of micro quantities of amino acid arginine (Arg) is described in. this paper. The catalytic activity of cobalt in the reaction of oxidation of purpurin (1,2,4-trihydroxy-antraquinone, PP) by hydrogen peroxide in alkaline buffer solution decreases in the presence of micro quantities of arginine, because of the formation of the complex. Operating conditions for the successful determination of arginine were optimized. The optimized conditions yielded a theoretical detection limit of 1.45 mu g mL(-1). Kinetic equations are proposed for the investigated process. The interference effects of certain foreign ions and amino acids upon the reaction rate were studied and removed in order to assess the selectivity of the method. The developed procedure was successfully applied to the determination of arginine in various pharmaceutical samples. The typical feature of this procedure is that determination can be carried out at room temperature and in a short analysis time. The newly developed method is simple, inexpensive and efficient for use in the analysis of a large number of samples.