Iron-chelating agents never suppress Fenton reaction but participate in quenching spin-trapped radicals

Linxiang Li, Yoshihiro Abe, Kiyotada Kanagawa, Tomoko Shoji, Tadahiko Mashino, Masataka Mochizuki, Miho Tanaka, Naoki Miyata

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Hydroxyl radical formation by Fenton reaction in the presence of an iron-chelating agent such as EDTA was traced by two different assay methods; an electron spin resonance (ESR) spin-trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and high Performance liquid chromatography (HPLC)-fluorescence detection with terephthalic acid (TPA), a fluorescent probe for hydroxyl radicals. From the ESR spin-trapping measurement, it was observed that EDTA seemed to suppress hydroxyl radical formation with the increase of its concentration. On the other hand, hydroxyl radical formation by Fenton reaction was not affected by EDTA monitored by HPLC assay. Similar inconsistent effects of other iron-chelating agents such as nitrylotriacetic acid (NTA), diethylenetriamine penta acetic acid (DTPA), oxalate and citrate were also observed. On the addition of EDTA solution to the reaction mixture 10 min after the Fenton reaction started, when hydroxyl radical formation should have almost ceased but the ESR signal of DMPO-OH radicals could be detected, it was observed that the DMPO-OH{radical dot} signal disappeared rapidly. With the simultaneous addition of Fe(II) solution and EDTA after the Fenton reaction ceased, the DMPO-OH{radical dot} signal disappeared more rapidly. The results indicated that these chelating agents should enhance the quenching of [DMPO-OH]{radical dot} radicals by Fe(II), but they did not suppress Fenton reaction by forming chelates with iron ions.

Original languageEnglish
Pages (from-to)315-319
Number of pages5
JournalAnalytica Chimica Acta
Volume599
Issue number2
DOIs
Publication statusPublished - 2007 Sep 19

Keywords

  • 5,5-Dimethyl-1-pyrroline N-oxide
  • Electron spin resonance
  • Ethylenediamine tetraacetic acid
  • Fenton reaction
  • Hydroxyl radical

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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