POLAROGRAPHIC-DETERMINATION OF EDTA IN CERTAIN PHARMACEUTICAL DOSAGE FORMS

A highly sensitive polarographic method was developed for the determin ation oi. EDTA added as a preservative in certain pharmaceutical prepa rations. The method involved chelation with Eu(III) followed by polaro graphic measurement of the chelate formed. A well-defined cathodic wav e was developed in Britton-Robinson buffers over the pH range 2-12. Th e wave was characterized as being quasi-reversible and diffusion contr olled. The current-concentration relationship was found to be rectilin ear over the ranges 8-160 and 2-120 mu g ml(-1), using DCt and DPP mod es, respectively, with limit of detection of 0.1 mu g ml(-1) using the DDP technique. The mechanism of the electrode reaction was verified. The proposed method was applied for the determination of EDTA in certa in pharmaceutical dosage forms, and the results obtained were in agree ment with those obtained by a reference method. (C) 1998 Elsevier Scie nce B.V. All rights reserved.