Influence of acidification on the optical properties and molecular composition of dissolved organic matter

Malak M. Tfaily, David C. Podgorski, Jane E. Corbett, Jeffrey P. Chanton, William T. Cooper

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Acidification is a common method for preserving dissolved organic matter (DOM) in natural water samples until sophisticated laboratory analyses can be performed. However, little is known about the effects of this practice on the composition and optical properties of DOM. In this study, the effects of acidification on DOM in porewater samples collected from the RL IV bog system of the Glacial Lake Agassiz Peatlands in northern Minnesota were characterized. Molecular composition was determined by ultrahigh resolution mass spectrometry and optical properties by UV absorption and three-dimensional fluorescence spectroscopy. Excitation-emission matrix fluorescence spectroscopy results indicate that the fluorescence properties of the peatland porewater DOM were sensitive to pH and that the observed changes were fluorophore dependent. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry revealed the appearance of newly formed, oxygen-rich compounds upon acidification. The extent to which these oxygen-rich compounds were formed was also dependent on the composition of the DOM.

Original languageEnglish (US)
Pages (from-to)261-267
Number of pages7
JournalAnalytica Chimica Acta
Issue number2
StatePublished - Nov 14 2011
Externally publishedYes


  • Dissolved organic matter (DOM)
  • Excitation-emission matrix fluorescence spectroscopy
  • Molecular composition
  • Optical properties
  • Sample preservation
  • Ultrahigh resolution mass spectrometry of DOM
  • UV-vis spectroscopy

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy


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