High-pressure size exclusion chromatography analysis of dissolved organic matter isolated by tangential-flow ultra filtration

Limnology and Oceanography
By: , and 

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Abstract

A 1,000-Dalton tangential-flow ultrafiltration (TFUF) membrane was used to isolate dissolved organic matter (DOM) from several freshwater environments. The TFUF unit used in this study was able to completely retain a polystyrene sulfonate 1,800-Dalton standard. Unaltered and TFUF-fractionated DOM molecular weights were assayed by high-pressure size exclusion chromatography (HPSEC). The weight-averaged molecular weights of the retentates were larger than those of the raw water samples, whereas the filtrates were all significantly smaller and approximately the same size or smaller than the manufacturer-specified pore size of the membrane. Moreover, at 280 nm the molar absorptivity of the DOM retained by the ultrafilter is significantly larger than the material in the filtrate. This observation suggests that most of the chromophoric components are associated with the higher molecular weight fraction of the DOM pool. Multivalent metals in the aqueous matrix also affected the molecular weights of the DOM molecules. Typically, proton-exchanged DOM retentates were smaller than untreated samples. This TFUF system appears to be an effective means of isolating aquatic DOM by size, but the ultimate size of the retentates may be affected by the presence of metals and by configurational properties unique to the DOM phase.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title High-pressure size exclusion chromatography analysis of dissolved organic matter isolated by tangential-flow ultra filtration
Series title Limnology and Oceanography
DOI 10.4319/lo.1999.44.5.1316
Volume 44
Issue 5
Year Published 1999
Language English
Publisher Wiley
Contributing office(s) Toxic Substances Hydrology Program
Description 7 p.
First page 1316
Last page 1322