Simultaneous Voltammetric Determination of Uric Acid, Xanthine, and Hypoxanthine Using CoFe₂O₄/Reduced Graphene Oxide-Modified Electrode

Abstract

<jats:p>In the present paper, the synthesis of cobalt ferrite/reduced graphene oxide (Co<jats:sub>2</jats:sub>Fe<jats:sub>2</jats:sub>O<jats:sub>4</jats:sub>/rGO) composite and its use for the simultaneous determination of uric acid (UA), xanthine (XA), and hypoxanthine (HX) is demonstrated. Cobalt ferrite hollow spheres were synthesized by using the carbonaceous polysaccharide microspheres prepared from a <jats:italic>D-</jats:italic>glucose solution as templates, followed by calcination. The CoFe<jats:sub>2</jats:sub>O<jats:sub>4</jats:sub>/rGO composite was prepared with the ultrasound-assisted method. The obtained material was characterized by using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, EDX elemental mapping, and nitrogen adsorption/desorption isotherms. The electrochemical behavior of UA, XA, and HX on the CoFe<jats:sub>2</jats:sub>O<jats:sub>4</jats:sub>/rGO-modified electrode was studied with cyclic voltammetry and differential pulse voltammetry (DPV). The modified electrode exhibits excellent electrocatalytic activity towards the oxidation of the three compounds. The calibration curves for UA, XA, and HX were obtained over the range of 2.0–10.0 <jats:italic>μ</jats:italic>M from DPV. The limits of detection for UA, XA, and HX are 0.767, 0.650, and 0.506 <jats:italic>μ</jats:italic>M, respectively. The modified electrode was applied to the simultaneous detection of UA, XA, and HX in human urine, and the results are consistent with those obtained from the high-performance liquid chromatography technique.</jats:p>