A nanodiamond-based electrochemical sensor for the determination of pyrazinamide antibiotic.

The application of nanodiamond (ND) in the preparation of an electrochemical sensor for the determination of pyrazinamide (PZA), one of the most consumed antibiotics for the treatment of tuberculosis, is proposed. The electrochemical sensor was constructed by the modification of a glassy carbon electrode (GCE) with an aqueous ND dispersion. The morphological characterization of the obtained ND film was carried out by scanning and transmission electron microscopy (SEM and TEM), and the electrochemical characterization assays were performed for the bare GCE and modified ND-GCE using potassium ferricyanide as redox probe. This redox probe showed an enhanced response on the ND-GCE, a higher electroactive surface area and a higher heterogeneous electron transfer rate constant ( k 0 ). The ND-GCE was employed in the PZA determination using square-wave voltammetry, and the obtained analytical curve was linear from 7.9 × 10 −7 to 4.9 × 10 −5 mol L −1 , with a limit of detection of 2.2 × 10 −7 mol L −1 . The proposed voltammetric method was successfully applied in the PZA determination in biological samples, with excellent recovery percentages. The proposed sensor architecture was notable for its simplicity of preparation and sensitivity towards the PZA drug, representing an interesting achievement in the preparation of nanodiamond-based electrochemical sensors. [ABSTRACT FROM AUTHOR]