Bilirubin sensor based on CuO-CdO composites deposited in a nafion/glassy carbon electrode matrixes

Copper oxide-cadmium oxide nanocomposites (CuO-CdO NCs) were synthesized by solvothermal technique in a basic medium. CuO-CdO NCs were characterized using conventional techniques, such as Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible Spectroscopy (UV/Vis), Field-Emission Scanning Electron Microscopy (FESEM), X-ray electron dispersive spectroscopy (XEDS), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (XRD). A selective and enzyme-less Bilirubin (BLR) sensor was developed with a thin-layer of NCs onto a glassy carbon electrode (GCE, surface area = 0.0316 cm²) using 5% nafion binders at room conditions. Improved electrochemical performances of higher sensitivity, lower detection limit, linear dynamic range (LDR), and long-term stability of preferred BLR were achieved by a reliable current-voltage (I-V) approach. The calibration curve was found linear (R² = 0.9347) in a wide range of BLR concentration (10.0 pM ~ 10.0 mM). Based on the signal to noise ratio value of 3, the sensitivity and limit of detection (LOD) of the sensor were calculated as 95.0 pA μM⁻¹ cm⁻² and 1.0 ± 0.1 pM respectively. Solvothermally synthesized CuO-CdO NCs/GCE is an excellent advancement of developing a selective and sensitive BLR sensor by electrochemical approach and practically implemented in real sample applications.