Direct electrochemistry and electrocatalysis of hemoglobin on carbon ionic liquid electrode

Hemoglobin in agarose was successfully immobilized on a carbon ionic liquid electrode and the direct electrochemical behavior of hemoglobin was investigated. Room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was used as the modifier. Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry were used to characterize the hemoglobin on the modified electrode. The results showed that the immobilized hemoglobin retained its bioelectrocatalytic activity. The electrochemistry of hemoglobin provided an opportunity to manufacture a third generation of biosensors. Experimental conditions influencing the biosensor performances such as pH, and potential were optimized and assessed. Under the optimal conditions, hydrogen peroxide was detected in the concentration range from 2 × 10−6 to 1.2 × 10−3 M with a detection limit of 0.2 μM at S/N = 3. The apparent Michaelis–Menten constant was 1.495 mM. The biosensor exhibited some advantages, such as short time respond, high sensitivity, good reproducibility and long-term stability.