Novel sonochemical synthesis of Fe3O4 nanospheres decorated on highly active reduced graphene oxide nanosheets for sensitive detection of uric acid in biological samples

•Magnetic properties based Fe3O4 NPs@rGOS nanocomposite have been.•The Fe3O4 NPs@rGOS nanocomposite has used for electrochemical sensor application.•The Fe3O4 NPs@rGOS nanocomposite has been developed pico-molar LOD.•Such a unique nanocomposite was successfully applied to the real sample analysis. In this study, a super-active Iron (II, III) oxide nanospheres (Fe3O4 NPs) decorated reduced graphene oxide (rGOS) nanocomposite was developed. Fe3O4 NPs were stabilized on rGOS through electrostatic interactions in the aqueous medium. This process involves an ultrasound assisted reduction reaction of the GOS. The as-synthesized Fe3O4 NPs@rGOS was characterized through the HRTEM, SEM, XRD, Raman, elemental mapping and EDX analysis. The Fe3O4 NPs@rGOS modified GCE was developed for the determination of biomarker. Uric acid is important biomarker based on gout and kidney stone with high adverse effect in human body. The results obtained showed that the modified electrode Fe3O4 NPs@rGOS shows good electrochemical reduction peak compared to bare electrode and control electrodes. The Fe3O4 NPs@rGOS modified sensor linear range 0.02–783.6 µM was observed with nanomolar LOD 0.12 nM. In addition, the modified Fe3O4 NPs@rGOS/GCE sensor has been applied to determination of uric acid concentration in urine and blood serum samples. Furthermore, advantages of the modified sensor are high stability, repeatability and reproducibility.