Département de chimie moléculaire

Horseradish peroxidase (HRP) was successfully incorporated into the laponite/chitosan (Chit)-modified glassy carbon electrode (GCE) using step-by-step self-assembly. The self-assembly processes were monitored by XPS and electrochem. impedance spectra (EIS). Direct electrochem. and electrocatalysis of the self-assembled HRP were investigated. Cyclic voltammetry of HRP/laponite/Chit/GCE, in anaerobic phosphate buffer soln. (0.025 M PBS, pH 7.0), displayed a pair of stable and quasi-reversible peaks at potentials E pa = 0.024 V and E pc = -0.132 V vs.SCE, attributed to the HRP-Fe(III)/HRP-Fe(II) redox couple. The electrochem. reaction of the HRP/laponite/Chit/GCE exhibited a surface-controlled electrode process. The electron transfer rate const. was estd. to be 1.82 s-1. The self-assembled HRP maintained its biol. activity and exhibited an excellent electrocatalytic performance for the redn. of H2O2 with fast amperometric response (10 s), broad linear range (2.9 × 10-5 to 1.4 × 10-3 M), good sensitivity (19.7 ± 0.5 mA M-1 cm-2) and low detection limit (5 × 10-6 M) at a signal-to-noise ratio of 3. Moreover, the inhibitory of sulfide to the self-assembled HRP was also investigated. [on SciFinder(R)]