A ceria NPs decorated graphene nano-composite sensor for sulfadiazine determination in pharmaceutical formulation

Since the importance of sulfonamide compound determinations, in this work, Sulfadiazine (SDZ), one of the significant sulfonamide antibiotics was electrochemically studied. SDZ is listed as world health organization (WHO) crucial medications in treatment of basic health system. A new graphene based nano-composite electrode was made and used for the electrochemical studies of some sulfondiamides. Electrochemical behavior of the compounds was initially investigated on bare and modified carbon paste electrodes using cyclic voltammetry (CV). The modifiers include Ceria (CeO₂) NPs, reduced graphene oxide (RGO) and RGO decorated CeO₂ NPs. The composition of 5% RGO decorated CeO₂ nanoparticles, 65% graphite, and 30% paraffin presented the best redox response for Sulfadiazine. Then, the nano-composite electrode was applied for SDZ measurement by fast Fourier transform square wave voltammetry (FFTSWV) on the proposed nano-composite electrode. Response linear range was obtained for 3–10 µM (R² = 0.9956) and 30–1000 µM (R² = 0.9948) of SDZ concentration, respectively, with LOD of 0.17 µM and LOQ of 3 µM. Finally, SDZ content in some pharmaceutical formulations were effectively analyzed by the proposed method and acceptable relative error of 4.6% was achieved.