Electrochemistry and electrocatalysis of myoglobin on carbon coated Fe₃O₄ nanospindle modified carbon ionic liquid electrode

In this paper, carbon coated Fe₃O₄ nanospindles (C@Fe₃O₄ NSs) were synthesized by partial reduction of monodispersed hematite nanospindles with carbon coatings and applied to investigate the direct electrochemistry of myoglobin (Mb). A novel modified electrode was prepared by applying carbon coated Fe₃O₄ nanospindles, Mb, ionic liquid (IL), 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM]EtOSO₃) and chitosan (CTS) step by step onto the surface of a carbon ionic liquid electrode (CILE) with another ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄), as the binder. UV-Vis absorption and FT-IR spectra results indicated that Mb retained its native structure in the composite film. The electrochemical behavior of the CTS/IL/Mb/C@Fe₃O₄/CILE was investigated and a pair of well-defined redox peaks appeared, which indicated that the direct electron transfer of Mb was realized with the underlying electrode. The fabricated CTS/IL/Mb/C@Fe₃O₄/CILE showed good electrocatalytic activity in the reduction of trichloroacetic acid (TCA) with a linear range from 1.0 to 20.0 mM, which showed potential applications for fabricating novel electrochemical biosensors and bioelectronic devices.