Carbonaceous nanomaterials integrated carbon paste sensors for adsorptive anodic voltammetric determination of butenafine in the presence of its degradation product

Abstract

Butenafine (BUT) is a new synthetic benzylamine antifungal with an effective inhibitory effect on squalene epoxidase. The present work introduced for the first time a novel sensitive adsorptive differential pulse voltammetric method for sensitive and selective determination of butenafine in pharmaceutical preparations in the presence of its degradation products. Integration of the working carbon paste electrodes with various carbonaceous nanostructures with their enhanced electrocatalytic effect towards the oxidation of butenafine improved the performance of the method. Comprehensive and in-depth studies were performed including the effect of the nature of the nanomaterial, modification mode, and pH under the optimized electroanalytical parameters. Functionalized carbon paste electrodes with multiwall carbon nanotubes (MWCNTs) showed a sharp well-defined oxidation peak for butenafine at 1.119 V following an adsorption electrode reaction mechanism through the participation of one proton/electron, as assumed by the pH, scan rate studies and molecular orbital calculations. Improved sensitivity was recorded within the linear BUT concentration range from 2.0 to 18.0 µg mL−1 with limit of detection 0.477 µg mL−1. A prolonged operational lifetime of more than 4 months and high measurement reproducibility was the promising futures of the fabricated sensors. The selectivity of the proposed method was established in the presence of the BUT degradation product and other interfering species present in pharmaceutical formulations. The achieved selectivity and sensitivity suggested the application of the proposed approach for BUT assay in medicinal creams in the presence of butenafine degradation products.