Electrochemistry and Electrocatalysis of a Nafion/Nano‐CaCO3/Hb Film Modified Carbon Ionic Liquid Electrode Using BMIMPF6as Binder
- Resource Type
- Article
- Authors
- Sun, Wei; Gao, Rui‐fang; Jiao, Kui
- Source
- Electroanalysis; July 2007, Vol. 19 Issue: 13 p1368-1374, 7p
- Subject
- Language
- ISSN
- 10400397; 15214109
In this paper a room temperature ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6) was used as binder for the construction of carbon ionic liquid electrode (CILE) and a new electrochemical biosensor was developed for determination of H2O2by immobilization of hemoglobin (Hb) in the composite film of Nafion/nano‐CaCO3on the surface of CILE. The Hb modified electrode showed a pair of well‐defined, quasi‐reversible redox peaks with Epaand Epcas −0.265 V and −0.470 V (vs. SCE). The formal potential (E°′) was got by the midpoint of Epaand Epcas −0.368 V, which was the characteristic of Hb Fe(III)/Fe(II) redox couples. The peak to peak separation was 205 mV in pH 7.0 Britton–Robinson (B–R) buffer solution at the scan rate of 100 mV/s. The direct electrochemistry of Hb in the film was carefully investigated and the electrochemical parameters of Hb on the modified electrode were calculated as α=0.487 and ks=0.128 s−1. The Nafion/nano‐CaCO3/Hb film electrode showed good electrocatalysis to the reduction of H2O2in the linear range from 8.0 to 240.0 μmol/L and the detection limit as 5.0 μmol/L (3σ). The apparent Michaelis–Menten constant (KMapp) was estimated to be 65.7 μmol/L. UV‐vis absorption spectroscopy and FT‐IR spectroscopy showed that Hb in the Nafion/nano‐CaCO3composite film could retain its native structure.