Enhanced electrochemical response of carbamazepine at a nano-structured sensing film of fullerene-C60 and its analytical applications

In the present work, electrochemical behavior of carbamazepine (CBZ) at fullerene-C₆₀ modified glassy carbon electrode has been investigated. Cyclic voltammogram of CBZ showed two each of oxidation and reduction peaks at fullerene-C₆₀ modified glassy carbon electrode (GCE) in phosphate buffer of pH 7.2 at the scan rate of 100 mV s⁻¹. The fullerene film on GCE surface exhibited excellent enhancement effects on electrochemical response of CBZ. Marked negative shift in peak potential with enhanced peak current was noticed in the cyclic and differential pulse voltammograms of CBZ at fullerene-C₆₀ modified electrode. The effect of accumulation time, amount of fullerene-C₆₀ and pH on electrochemical behavior of CBZ has been investigated using differential pulse voltammetry (DPV). An analytical method was developed for the determination of CBZ employing DPV. The oxidation peak current of CBZ was observed to be linearly dependent on the concentration of CBZ in the range of 90 nM–10 μM. The values of limit of detection and limit of quantification were found to be 16.2 nM and 54.0 nM, respectively. The developed DPV method was satisfactorily applied to the determination of CBZ in pharmaceutical formulations, spiked human serum and urine samples.     

Electrochemical investigations of an anticancer drug in the presence of sodium dodecyl sulfate as an enhancing agent at carbon paste electrode

In the present work, the electrochemical behavior of an anticancer drug, gemcitabine hydrochloride (GMB) was studied in the presence of a surface active agent (surfactant) at carbon paste electrode (CPE). GMB showed an oxidation peak at 1.101 V. The presence of sodium dodecyl sulfate (SDS) in the electrolyte was found to enhance the oxidation signal of GMB at CPE. The oxidation peak current of GMB in the presence of SDS was observed to be the function of accumulation time, scan rate, pH of the medium, and concentration of GMB. Accumulation time greatly influenced the peak current but did not exhibit significant influence on the peak potential. Based on this, a novel, sensitive, and convenient differential pulse voltammetric method was developed for the determination of GMB in the concentration range of 5.0 × 10⁻⁸–3.0 × 10⁻⁴ M with a limit of detection value of 8.2 × 10⁻⁹ M. The proposed procedure was successfully applied for the determination of GMB in pharmaceutical formulations and spiked biological samples.