Cathodic adsorptive stripping voltammetric determination of the anti-inflammatory drug indomethacin

Abstract

Sensitive voltammetric methods have been developed for the determination of the anti-inflammatory, anti-pyretic and analgesic drug indomethacin sodium. The methods are based on the controlled adsorptive preconcentration of the drug on a hanging mercury drop electrode (HMDE), followed by tracing the voltammogram in a cathodic potential scan. The modes used are cyclic voltammetry (CV), cathodic stripping voltammetry (CSV) and differential pulse stripping voltammetry (DPSV). Amounts as low as 10 nM (10 ng ml −1) (60 s preconcentration) by CSV and 0.5 μM (190 ng ml −1) (300 s) by DPSV can be determined accurately. The R.S.D. at the 1×10 −6 M level is 1.4%. The interference of some metal ions and the application of the method to analysis of urine, plasma and pharmaceutical formulations are described.