Simultaneous determination of ascorbic acid, uric acid, tryptophan and adenine using carbon-supported NiCoO2 nanoparticles

• NiCoO2 NPs based electrochemical sensor was fabricated.
• The incorporation of cobalt into nickel oxide matrix enhances the electrochemical performance of the electrodes.
• Electrode was used for simultaneous determination of AA, UA, Trp and adenine.
• The sensor was used to determine the four analytes in many real samples with satisfactory results.

The electrochemical sensor based on carbon-supported NiCoO2 nanoparticles (NiCoO2/C) modified glassy carbon electrode (GCE) was constructed to simultaneously determine small biomolecules such as ascorbic acid (AA), uric acid (UA), tryptophan (Trp) and adenine. The morphology and structure of NiCoO2 nanoparticles (NPs) were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry and Fourier transform infrared spectroscopy. Electrochemical studies of simultaneous detection were carried out by differential pulse voltammetry (DPV). The combination of Ni and Co oxides endowed the NiCoO2/C modified GCE with electrocatalytic activity, sensitivity, and selectivity with well-separated oxidation peaks toward AA, UA, Trp and adenine. Two linear calibrations for AA, UA, Trp and adenine were obtained over ranges of 5.0 × 10−5–485.4 × 10−6 and 485.4 × 10−6–943.4 × 10−6 M with detection limit (S/N = 3) of 3.3 × 10−6, 5.3 × 10−6, 5.7 × 10−6 and 3.9 × 10−6 M respectively. In addition, the modified electrode was successfully applied for the simultaneous determination of AA, UA, Trp, and adenine in many real samples with reliable recovery.