Sensitive electrochemical analysis of uricosuric drug sulfinpyrazone using a graphene-based sensor: A first voltammetric approach

The novel electrochemical sensor was employed for the investigation of the uricosuric drug sulfinpyrazone (SLF), which is administered orally to treat gout and prevent stone formations. SLF is toxic to the liver and increases the risk of Stevens-Johnson syndrome and toxic epidermal necrolysis, which are life-threatening conditions. It is crucial to avoid aspirin, salicylates, and similar salicylic acid derivatives when taking uricosuric drugs, as salicylates can inhibit tubular uric acid secretion, especially at lower doses. Thus, determining SLF is highly significant. In the pursuit of intensive care and interactions involving SLF, an r-GO@CPE (reduced graphene oxide modified carbon paste electrode) was employed for the study of SLF. Various characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray diffraction spectrum (EDS), Fourier Transform Infrared Spectroscopy (FTIR) and electron impedance spectroscopy (EIS), were utilized to analyse the electrode modifier. The resulting r-GO@CPE has an enriched electroactive surface area, a high standard heterogeneous rate constant (k_et), and a small charge resistance (R_ct) as compared with the Carbon paste electrode, which authenticates its good catalytic activity. The analytical investigation of SLF was achieved through voltametric techniques such as cyclic & square wave voltammetry (CV & SWV). Optimal results were attained at a pH of 9.2, revealing an oxidation peak within the potential range of 0.2–1.2 V. SWV was employed for the quantitative estimation of SLF, yielding a limit of detection (LOD) and a limit of quantification (LOQ) of 1.10 × 10⁻⁸ M and 3.6 × 10⁻⁸ M respectively. This novel approach was also applied to determine SLF concentrations in both biological, water & pharmaceutical samples.