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

The electrochemical sensor based on carbon-supported NiCoO 2 nanoparticles (NiCoO 2 /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 NiCoO 2 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 NiCoO 2 /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.