Peroxidase mimicking: Fe(Salen)Cl modified electrodes, fundamental properties and applications for biosensing

Yea Wenn Liou, Chong Mou Wang

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Iron(lII) N,N′-bis(salicylidene)ethylenediamine (denoted as Fe(Salen)+) was prepared and characterized for its application in chemical analysis. From the stability constant of Fe(III)(Salen)+ (7.1×1025 M-1) and the formal potentials of Fe3+/2+ and Fe(Salen)+/0, the stability constant of Fe(II)(Salen) was calculated to be 3×1017 M-1. This relatively weaker stability constant, compared with that of Fe(III)(Salen)+, led to the occurrence of the electron transfer reactions between Fe(Salen) and electron acceptors, like oxygen and H2O2. Experimental results supported this hypothesis, showing that the pseudo-first order rate constants for the reactions of Fe(II)(Salen) with O2 (DMSO-H2O, v/v 4:1) and H2O2 (pH 7) are 330 and 4400 M-1 s-1, respectively. Because of this catalytic effect, a sensing electrode for glucose or uric acid was constructed on the basis of Fe(Salen)+ and glucose oxidase (GOx) or uricase (UOx). According to the flow injection analysis (FIA). the detection limits were 1 μm for glucose at pH 7 and 0.1 μM for uric acid at pH 8.5, respectively. The linear response to each substrate covered a region of 1 μM-10 mM for glucose and 5-40 μM for uric acid. Fe(Salen)+ might form a 1:1 adduct with β-cyclodextrin (β-CDx); the equilibrium constant was determined to be about 6 M-1. Although this chemical equilibrium, in terms of the numerical value, was not significant, the formation of {Fe(Salen)}2O was effectively limited as β-CDx was incorporated.

Original languageEnglish
Pages (from-to)102-109
Number of pages8
JournalJournal of Electroanalytical Chemistry
Volume481
Issue number1
DOIs
Publication statusPublished - 2000 Jan 31

    Fingerprint

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

Cite this