DOM Molecular Weight Fractionation and Fluorescence Quantum Yield Assessment Using a Coupled In-Line SEC Optical Property System

Blair Hanson, Urban Wünsch, Shelby Buckley, Sarah Fischer, Frank Leresche, Kathleen Murphy, Juliana D’Andrilli, Fernando L. Rosario-Ortiz*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Size exclusion chromatography (SEC) in combination with optical measurements has become a popular form of analysis to characterize dissolved organic matter (DOM) as a function of molecular size. Here, SEC coupled with in-line absorbance scans and fluorescence emission scans was utilized to derive apparent fluorescence quantum yield (Φf) as a function of molecular weight (MW) for DOM. Individual instrument-specific SEC-fluorescence detector correction factors were developed by comparison of an SEC-based excitation emission matrix (EEM) to an EEM generated by a calibrated benchtop fluorometer. The method was then applied to several sample sets to demonstrate how to measure the Φf of unknown DOM samples and to observe changes to Φf following a processing mechanism (ozonation). The Φf of riverine water samples and DOM fulvic acid isolates from Suwannee River and Pony Lake increased from < 0.5% to a maximum of ∼2.5–3% across the medium- to low-MW range. Following ozonation of PLFA, Φf increased most notably in the large-MW fractions (elution volumes < 40 mL). Overall, this method provides a means by which highly fluorescent size fractions of DOM can be identified for more detailed analyses of chemical composition and its changes through different processing mechanisms.
Original languageEnglish
JournalACS EST Water
Volume2
Issue number12
Pages (from-to)2491-2501
Number of pages11
ISSN2690-0637
DOIs
Publication statusPublished - 2022

Keywords

  • Dissolved organic matter
  • Size exclusion chromatography
  • Fluorescence
  • Quantum yield
  • Ozone
  • Optical properties

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