Acid Extraction Overestimates the Total Fe(II) in the Presence of Iron (Hydr)oxide and Sulfide Minerals

Man Jae Kwon, Jung Seok Yang, Moo Joon Shim, Maxim I. Boyanov, Kenneth M. Kemner, Edward J. O'Loughlin

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Acid extraction followed by a colorimetric assay is a widely used approach for the determination of the total Fe(II) in samples from suboxic and anoxic environments. Under sulfidogenic conditions, these samples can contain both metal sulfides and iron (hydr)oxides. Our comparisons between 0.5 N HCl extraction and X-ray absorption fine structure (XAFS) analysis of systems containing 40 mM Fe(III) as specific (hydr)oxides and 10 mM FeS showed that the presence of sulfide can result in significant overestimation of the total Fe(II) by acid extraction. The total Fe(II) determined by XAFS was consistent with the added FeS. However, the total Fe(II) determined by extraction was significantly higher and dependent on the nature of the Fe(III) (hydr)oxides; the rates and extent of Fe(II) production were higher with ferrihydrite and lepidocrocite than with goethite. Total Fe(II) concentrations determined following acid extraction might be overestimated when iron (hydr)oxides and sulfide minerals are present in samples.

Original languageEnglish
Pages (from-to)310-314
Number of pages5
JournalEnvironmental Science and Technology Letters
Issue number7
Publication statusPublished - 2014 Jul 8
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2014 American Chemical Society.

ASJC Scopus subject areas

  • Environmental Chemistry
  • Ecology
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


Dive into the research topics of 'Acid Extraction Overestimates the Total Fe(II) in the Presence of Iron (Hydr)oxide and Sulfide Minerals'. Together they form a unique fingerprint.

Cite this