Chronoamperometric Detection of Amoxicillin at Graphite Electrode using Chelate Effect of Copper(II) Ions : Application in Human Blood and Pharmaceutical Tablets

A novel electrochemical method is suggested for indirect chronoamperometric determination of amoxicillin (AMX) in the presence of copper ions Cu (II) at carbon paste electrode (CPE). The method is based on the interaction between the β‐lactam antibiotic and copper ions. This interaction was firstly studied by square wave voltammetry (SWV), where the peak corresponding to the oxidation of AMX at 0.7 V decreases significantly in the presence of copper ions. The reaction product is characterized by UV‐visible spectrophotometry and Infrared spectroscopy (IR). Moreover, when AMX was added to supporting electrolyte containing copper ions, the chronoamperometric current of the Cu(II)/Cu(I) redox system was increased. Hence, this increase in the current was used for indirect determination of amoxicillin. By selecting an appropriate concentration of copper (II), the calibration curve for AMX was established in the concentration range of 1.95×10−7 to 1.46×10−5 mol L−1. The detection limit was found to be 8.84× 10−8 mol L−1. The influence of different organic compounds on the AMX determination and the effect of coexisting of other metal ions in the electrolytic solution were studied. The applicability of the proposed method was tested in human blood and pharmaceutical tablets. A new electrochemical method was investigated for the indirect determination of AMX at CPE based on its interaction with Cu(II) ions. This novel electrochemical method demonstrates excellent performance for the determination of amoxicillin in human blood and pharmaceutical tablets.