Electrochemical sensor for amoxicillin using Cu/poly (o-toluidine) (sodium dodecyl sulfate) modified carbon paste electrode

Poly(o-toluidine) (sodium dodecyl sulfate) (POT(SDS)) film was electrosynthesized on carbon paste electrode (CPE) by using the cyclic voltammetry technique in aqueous solution containing o-toluidine (OT), sulfuric acid and SDS. Then, copper oxide was incorporated by immersion of POT(SDS)/CPE in a solution of copper sulfate and using constant potential method. Then, the electrochemical characterization of the modified electrode is presented in alkaline solution. For the first time, electrochemical behaviour of amoxicillin (AMX) at the Cu/POT(SDS)/CPE has been investigated using cyclic voltammetry (CV) and chronoamperometric method. The experimental results suggest that the modified electrode exhibits electrocatalytic effect on the oxidation of AMX resulting in a marked enhancement of the anodic peak current response. Under the selected conditions, the anodic peak current was linearly dependent on the concentration of AMX in the range 80-200 and 5-150 mu M with CV and amperometric method, respectively. The detection limits (2 delta) were also estimated to be 60 and 3 mu M. Some kinetic parameters such as the transfer second-order rate constant (k = 4.9 x 10(6) cm(3) mol(-1) s(-1)) of AMX was calculated. Therefore, this modified electrode was a simple, rapid and new electrode to determine AMX in pharmaceutical preparations.