Voltammetric determination of ketoconazole using a polished silver solid amalgam electrode

This paper describes the use of a polished silver solid amalgam electrode (p-AgSAE) evaluation of its electrochemical behaviour and the development of an electroanalytical procedure for the determination of ketoconazole (KC) in pharmaceutical formulations The experimental and voltammetric conditions were evaluated and the best responses were obtained in BR buffer (pH 12 0) with f= 100 s(-1) a = 25 mV and Delta E-s = 2 mV Under these conditions the voltammetric response of KC presented a well-defined and quasi-reversible reduction peak at around 1 46 V vs Ag/AgCl/Cl- at 3 0 mol V Analysis of a purified laboratory electrolyte using the proposed methodology allowed for responses that were directly proportional to KC concentration and the analytical sensitivity was comparable to published results using mercury electrodes and solid surfaces such as carbon paste gold and platinum electrodes The recovery percentages in pure electrolyte as well as tablet shampoo and cream samples showed values from 90 to 105% demonstrating that the voltammetric methodology proposed is suitable for determining KC in complex samples The method has excellent robustness and specificity for analytical purposes minimises toxic residues due to the use of liquid mercury and avoids adsorptive processes related to the use of other solid surfaces Published by Elsevier Ltd