Electrodeposition CaCO3 Nanoparticles‐chitosan Composite Film on Carbon Ionic Liquid Electrode as a Platform for Hemoglobin Electrochemical Biosensor

By one‐step co‐electrodeposition CaCO₃ nanoparticles‐chitosan composite film on carbon ionic liquid electrode (CILE), and then by spreading the composition of hemoglobin (Hb) and chitosan on the nanoCaCO₃‐chi/CILE, a Hb‐chi/nanoCaCO₃‐chi/CILE was fabricated and the direct electrochemistry and electrocatalysis of Hb at the electrode was investigated. The electrochemical impedance spectroscopy of the modified electrode showed the electron transfer resistance was 1166 Ω. Investigation results of cyclic voltammetrys showed a pair of well‐defined and quasireversible redox peak of Hb with the formal potentials of ‐0.295 V (vs. SCE) in 0.1 mol·L^‐1 pH 7.0 PBS; the response time of the reduction peak currents of Hb was lower than 3s; a linear range for determination of H₂O₂ was from 5.0 μmol·L^‐1 to 1.3 mmol·L^‐1 with a detection limit of 1.6 μmol·L^‐1 (S/N = 3) and a sensitivity of 0.16 A·M^‐1·cm^‐2; the electron transfer rate constant and the apparent Michaelis‐Menten constant of Hb were 1.98 s^‐1 and 0.81 mmol·L^‐1, respectively. As a result, the case of the one‐step co‐electrodeposition and the promising feature of biocomposite could serve as a versatile platform for the fabrication of electrochemical biosensors.