Rutin as an Electrochemical Mediator in the Determination of Captopril using a Graphite Paste Electrode

A simple, rapid and sensitive cyclic voltammetry method is described for the determination of the antihypertensive drug captopril in aqueous solution using a graphite paste electrode with rutin as mediator. The catalytic role of rutin in the oxidation of captopril was confirmed by the increase observed in anodic peak current at+0.44 V vs. SCE in the presence of the mediator. Anodic peak current varied linearly with the concentration of captopril in the dynamic range 0.2 to 1.0 mmol L-1. The method exhibited a limit of detection of 89.4 mu mol L-1 and a reproducibility of 1 %, values that are comparable with those exhibited by other methodologies employing electrodes without any modification. The recovery rate for the determination of captopril in a pharmaceutical sample was good (91.21 %) suggesting that the described analytical technique would be effective in industrial applications whilst offering a number of advantages over published cyclic voltammetric methods.