Mercury Thin Film at Glassy Carbon Electrode for Adsorptive Stripping Voltammetric Determination of Captopril in Pharmaceutical Samples

A simple square-wave adsorptive voltammetric (SWAV) method was developed for determining Captopril (CAP) in pharmaceutical formulations. The proposed method was based on the electrochemical reduction of CAP at a mercury thin film electrode (MTFE). The preparation of the TMFE/Glassy carbon electrode was very simple; also, this electrode had very good reproducibility and regeneration of its surface was very easy. This kind of electrode has the advantages of mercury electrode and a negligible amount of mercury. In this study, the MTFE in situ produced on glassy carbon electrode to the adsorptive voltammetric quantification of trace amount of CAP. MTFE was shown to be extremely useful for the voltammetric measurements of CAP at μM level. Under optimized conditions, the SW adsorptive stripping voltammetric peak current showed linear correlation with drug concentration over the range of 4.6–64.5 μM with the correlation coefficient of 0.992. The detection limit at the S/N ratio of 3 was 0.6 μM for CAP (n=6) and the relative standard deviation for 23 μM of CAP (n=6) was 6.9%. The film electrode had the advantages of acceptable sensitivity, reproducibility, and simple preparation. The MTFE applied to determination of CAP in tablet samples with satisfactory results.