Electrocatalytic oxidation and differential pulse voltammetric determination of sulfamethoxazole using carbon nanotube paste electrode

The use of a carbon-nanotube paste electrode provides an effective means for the determination of sulfamethoxazole. A decrease of ca. 110 mV in the overpotential for the oxidation of sulfamethoxazole compared to a traditional carbon paste electrode is reported along with greatly enhanced signal-to-noise characteristics. The oxidation process was found to be dependent on the pH of the supporting electrolyte. Under the optimized conditions the calibration plots are linear in the concentration range of 0.35–30 μg mL− 1 with slope of 0.0955 μA/μg mL− 1, LOD 0.1 μg mL− 1 and LOQ 0.33 μg mL− 1. Application of the method for the determination of the drug in the form tablet or suspension, without any interference, from the excipients, resulted in acceptable deviation from the stated concentrations.

► This work examines electrooxidation of sulfamethoxazole at MWCNT’s paste electrode.
► The MWCNT’s electrode exhibits good electrocatalytic behavior toward SMX oxidation.
► This electrode offers a marked decrease on overvoltage for SMX oxidation.
► The MWCNT’s paste electrode has good stability and reproducibility.