Voltammetric Detection of Captopril Using Copper(II) and an Unmodified Glassy Carbon Electrode

Abstract

We report a simple, sensitive, and rapid detection of captopril using copper(II) and a bare glassy carbon electrode with cyclic voltammetry. The captopril is detected by the formation of a copper(II)‐captopril complex that is observed to have a characteristic oxidation potential at+0.24 V vs. Ag/AgCl. It is found that the peak current varies linearly with the concentration of captopril. The linear dynamic range is obtained for a captopril concentration of 1 µM to 10 µM, and the sensitivity is found to be 0.10±0.003 μA μM−1. Importantly, the low limit of detection (n=3) of 0.10 μM and the precision of 3.2 %, are achieved using a simple, unmodified electrode. This is attributable to in situ adsorption of a copper(II)‐captopril complex on the electrode surface.

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

“…This catalytic effect is attributed to the interaction between captopril and the flavonoid since, in the absence of rutin, the direct oxidation of captopril occurs at +1.37 V vs . SCE (Figure , green line) .…”

Voltammetric Determination of Captopril on a Glassy Carbon Electrode Modified with Copper Metal‐organic Framework

“…+0.24 V vs . Ag/AgCl , indicating that the oxidation of captopril occurs via formation of the copper(II)‐captopril complex compound. The displacement of the potential to more positive value may be related with surface effects of the MOF presence.…”

“…Such a low potential is an important advantage for analytical detection of this reagent. According to obtained results and the previous studies , the electrochemical oxidation of captopril on Cu‐BTC/GCE would be written as:…”

“…A previous report shows that in presence of copper(II) ions, captopril forms the copper(II)‐captopril complex compound. In order to understand the mechanism of oxidation of copper in absence (Figure A) and presence (Figure B) of captopril on Cu‐BTC/GCE, cyclic voltammograms in 0.1 M phosphate buffer pH 3.0 (the best condition) were obtained at different scan rates.…”

“…In this sense, electrochemical methods appear as promising in the replacing the conventional methods in the determination of captopril, mainly due to their simplicity, high sensitivity, rapid detection time and lower cost of analysis . The study of oxidation of thiols at solid electrodes was initially stimulated by the increasing interest in electrocatalysts such as phthalocyanine derivatives , organic mediators , or enzymes .…”