Electrocatalysis of hemoglobin in ionic liquid BMIMPF6 and CuS nanosphere composite films

Abstract

Ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆) was mixed homogeneously with nanometer-sized semiconductor CuS sphere to form a new nanocomposite material, which was further used for the immobilization of hemoglobin (Hb) on the surface of carbon paste electrode (CPE). Direct electrochemistry of Hb in BMIMPF₆-CuS composite film was carefully investigated with a pair of quasi-reversible redox peaks appeared and the formal potential (E^0') was got as -135 mV (vs. SCE) in pH 7.0 phosphate buffer solution, which was due to the enhanced direct electron transfer rate of Hb in the biocompatible matrix. The BMIMPF₆-CuS-Hb/CPE showed excellent electrocatalytic activity to the reduction of hydrogen peroxide with the kinetic parameters for the electrocatalytic reaction evaluated. The results indicated that the BMIMPF₆-CuS nanocomposite could be used for the preparation of electrochemical biosensor.

KEY WORDS: Hemoglobin, Direct electrochemistry, Copper sulfide nanosphere, 1-Butyl-3-methylimidazolium hexafluorophosphate, Hydrogen peroxide

Bull. Chem. Soc. Ethiop. 2011, 25(3), 443-450.