UV spectrophotometric microdetermination of L-DOPA based on complex formation with copper(II)ion

Abstract

The UV spectrophotometric investigations obtained for the reaction between L-DOPA and copper(II)ion contribute to the clarification of equilibrium conditions of the complex formation both in the excess of metal ion and ligand. For the complex obtained in the excess of copper(II)ion optimum conditions were established as well as the stoichiometric composition(1:1) and conditional stability constant logK' =5.70+/-0.05. The proposed method using copper(II)ion, as the analytical reagent in excess, for the UV spectrophotometric determination is suitable for accurate, sensitive and selective analysis of L-DOPA both in pure and dosage forms containing benzerazide.