Département de chimie moléculaire

A highly stable biol. film was formed on the functional glassy carbon electrode (GCE) via step-by-step self-assembly of chitosan (CHT), laponite, and Hb. Cyclic voltammetry (CV) of the Hb/laponite/CHT/GCE showed a pair of stable and quasi-reversible peaks for the Hb-Fe(III)/Fe(II) redox couple at about -0.035 V vs. a SCE in pH 6.0 phosphate buffer at a scan rate of 0.1 V s-1. The electrochem. reaction of Hb entrapped on the laponite/CHT self-assembled film exhibited a surface-controlled electrode process. The formal potential of the Hb-heme-Fe(III)/Fe(II) couple varied linearly with the increase of pH over the range of 3.0-8.0 with a slope of -63 mV pH-1, which implied that an electron transfer was accompanied by single-proton transfer in the electrochem. reaction. The position of the Soret absorption band of this self-assembled Hb/laponite/CHT film suggested that the entrapped Hb kept its secondary structure similar to its native state. The self-assembled film showed excellent long-term stability, the CV peak potentials kept in the same positions, and the cathodic peak currents retained 90{%} of their values after 60 days. The film was used as a biol. catalyst to catalyze the redn. of hydrogen peroxide. The electrocatalytic response showed a linear dependence on the H2O2 concn. ranging widely from 6.2 × 10-6 to 2.55 × 10-3 M with a detection limit of 6.2 × 10-6 M at 3 $\sigma$. [on SciFinder(R)]