Facile fabrication of CdS@GO binary nanocomposite coated GCE for separate and parallel electrochemical sensing of ascorbic acid, uric acid and nitrite

The accurate detection of vital biomarkers such as Ascorbic Acid (AA), Uric Acid (UA) and Nitrite (NO₂⁻) is crucial for human health surveillance. However, existing methods often struggle with concurrent detection and quantification of multiple species, highlighting the need for a more effective solution. To address this challenge, this study aimed to develop a multifunctional electrochemical sensor capable of parallel detection of AA, UA and NO₂⁻ using a synergistic combination of Graphene Oxide (GO) and Cadmium Sulfide (CdS) materials. Notably, the fabricated CdS@GO/Glassy Carbon Electrode (GCE) exhibited exceptional electrochemical activity, as evidenced by Differential Pulse Voltammetry (DPV) analysis. The sensor demonstrated remarkable sensitivity (8.13, 10.12, and 9.05 μA·μM⁻¹·cm⁻²) and ultra-low detection limits (0.034, 0.062, and 0.084 µM) for AA, UA and NO₂⁻, respectively. Furthermore, it successfully identified single molecules of each analyte in aqueous and biologic fluid samples, with recovery values comparable to those obtained using High-Performance Liquid Chromatography (HPLC) standard addition methods. The significance of this study lies in developing a novel CdS@GO/GCE sensor that enables concurrent detection and quantification of multiple vital biomarkers, offering a promising tool for human health monitoring and diagnosis.