Chinese Journal of Applied Chemistry ›› 2010, Vol. 27 ›› Issue (09): 1093-1098.DOI: 10.3724/SP.J.1095.2010.90783

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Reversible Oxidation of p-Phenylenediamine on Hemoglobin/poly(L-glutamic acid)/Glassy Carbon Modified Electrode

LI Min, YANG Chang-Ying*, ZHOU Wen-Kai, ZHU Min   

  1. (College of Chemistry and Life Science,China Three Gorges University,Yichang 443002)
  • Received:2009-11-26 Revised:2010-03-06 Published:2010-09-10 Online:2010-09-10

Abstract:

A hemoglobin/poly(L-glutamic acid)/glassy carbon electrode(Hb/PGA/GCE), targeted for reversible oxidation of p-phenylenediamine(PPD), has been fabricated by covalently immobilizing Hb on GCE with a thin layer of conductive preelectropolymerized PGA. Electrochemical impedance spectra of the electrode confirmed the immobilization of Hb. The resulting modified electrode(Hb/PGA/GCE) gave a redox couple for Hb in PBS buffer and a better electrocatalytic performance to H2O2. This indicated that the direct electron transfer of the active group of the protein could be retained on the electrode surface. The oxidation of PPD was reversible on Hb/PGA/GCE instead of GCE or PGA/GCE. The redox peak current was proportional to the scan rate, and Ip,a/Ip,c about 1.02, indicating a characteristic of quasi-reversible, surface confined electrochemical behavior. Moreover, a new measurement method for PPD in samples was provided since the redox peak currents increased linearly with the concentration of PPD, Ip,a(μA)=3.124+0.705cPPD(mmol/L)(r=0.9973). The enzymatic oxidation might be the plausible mechanism because the existence of H2O2 was in favor of the reversible redox of PPD.

Key words: hemoglobin (Hb), poly (L-glutamic acid) (PGA), p-phenylenediamine (PPD), reversible oxidation

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