LAUSR

New highly sensitive voltammetric method for captopril (CPT) determination was developed. The main novelty of the work was the application of a renewable amalgam film electrode (Hg(Ag)FE) for this purpose. During the research instrumental parameters of the developed method were optimized and were as follows: tw = ts = 5 ms, Es = 5 mV, ΔE = 100 mV. Preconcentration potential and time were equal to 100 mV and 20 s, respectively. All measurements were conducted in electrolyte consisted of 0.1 M HClO4. Limit of detection was calculated and was equal to 1.9 nM (0.39 ng mL-1) for 20 s preconcentration time and Hg(Ag)FE surface area approximately 11.2 mm2. Linearity was achieved in the concentration range 0.05-1 μM. Repeatability of the method expressed as variation coefficient was estimated at 3.5% (0.15 μM CPT, n = 10). Applicability of the method was confirmed by analysis of tablets containing CPT and urine. Recoveries were in the range from 95 to 109% suggesting that the method might be assumed as accurate. Obtained results were also in good agreement with the producer declaration.