Electrochemistry and electrocatalysis of cobalt(ii) immobilized onto gel-assisted synthesized zinc oxide nanoparticle–multi wall carbon nanotube–polycaprolactone composite film: application to determination of glucose

Abstract

Nanoparticles of zinc oxide were synthesized by a simple and low-cost method using gelatin as organic precursor. Techniques of X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the structure and property of the zinc oxide. The results show that the ZnO nanoparticles with high crystallinity can be obtained using this simple method. Gelatin plays an important role in the formation of the ZnO nanoparticles. Moreover, the composite film was prepared by synthesized ZnO nanoparticles, multi wall carbon nanotube (MWNT) and polycaprolactone (PCL) on glassy carbon electrode (ZnO–MWNT–PCL–GCE). The porous ZnO–MWNT–PCL film was used as a supporting matrix to immobilize Co(II) ions. Immobilized Co ions exhibit excellent electrocatalytic activities to glucose oxidation. The sensor responded linearly to glucose in the concentration of 5.0 × 10⁻⁵ to 6.0 × 10⁻³ M with detection limit of 1.6 × 10⁻⁵ M at 3σ using cyclic voltammetry (CV). Moreover, the studied biosensor exhibited good reproducibility and long-term stability. Furthermore, the fabricated electrode displayed voltammetry response to the glucose in human blood serum and the results were matched with referenced values obtained by the standard technique.