Magnetic core–shell Fe3O4@SiO2/MWCNT nanocomposite modified carbon paste electrode for amplified electrochemical sensing of uric acid

• A simple and rapid sensor for determination of UA in human blood serum and urine was prepared.
• The Fe3O4@SiO2/MWCNTs-CPE showed an obvious increase in surface area and sensitivity.
• The presence of Fe3O4@SiO2 nanoparticles showed good ability to distinguish the response of UA.

A new type of nanocomposite based on multi-walled carbon nanotubes decorated with magnetic core–shell Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2/MWCNTs) was prepared and used to fabricate a modified carbon paste electrode (CPE). The nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT-IR) techniques. Electrochemical behavior of uric acid (UA) was investigated on Fe3O4@SiO2/MWCNTs-CPE by cyclic voltammetry (CV) and square wave voltammetry (SWV) in phosphate buffer solution (pH 6.0). Under the optimized conditions, the peak currents increased linearly with the concentration of UA in the range from 0.60 to 100.0 μM, with a detection limit of 0.13 μM. The proposed sensor was successfully applied for the determination of UA in biological fluids.

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