An electrochemical sensor for selective detection of ascorbic acid (AA) in the presence of dopamine (DA) and uric acid (UA) was fabricated by modifying the glassy carbon electrode (GCE) with carbon-supported NiCoO2 (NiCoO2/C) nanoparticles. The electrochemical impedance spectroscopic (EIS) studies reveal the little charge transfer resistance for the modified electrode. The electrocatalytic activity of the modified electrode for the oxidation of AA was investigated. The current sensitivity of AA was enhanced to about five times upon modification. The voltammetric response of AA was well resolved from the responses of DA and UA, and the oxidation potential of AA was negatively shifted to -0.20 V. The biosensor tolerated a wide linear concentration range for AA, from 1.0 × 10(-5)M to 2.63 × 10(-3)M (R(2)=0.9929), with a detection limit of 0.5 μM (S/N = 3). Our results demonstrate that the NiCoO2/C nanomaterials has excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. That makes it a unique electrochemical sensor for the detection of AA which is free from the interference of DA, UA and other interferents.
Keywords: Ascorbic acid; Co; Dopamine; Electrochemical sensor; Ni; Uric acid.
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