Selective isolation of dissolved organic matter from aquatic systems

John R. Tuschall, Jr.; George, Gregory

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https://hdl.handle.net/2142/90361 Copy

Description

Title

Selective isolation of dissolved organic matter from aquatic systems

Author(s)

• John R. Tuschall, Jr.
• George, Gregory

Contributor(s)

Illinois State Water Survey

Issue Date

1984-06

Keyword(s)

• Water resource development--Illinois
• Water resource development
• Water quality
• Amino acids
• Ammonia
• Analytical techniques
• Anion exchange
• Bogs
• Carbon
• Cation exchange
• Chemical properties
• Chromatography
• Decomposing organic matter
• Dissolved organic matter
• DOM
• Fluorometry
• Fulvic acids
• Humates
• Humic acids
• Humus
• Isolation
• Lakes
• Liquid chromatography
• Nitrogen
• Organic matter
• Ponds
• Separation techniques
• Streams
• Surface waters
• Swamps
• Water chemistry
• Wetlands
• XAD resins

Geographic Coverage

Illinois (state)

Abstract

A chromatographic ion-exchange procedure for fractionation, isolation and concentration of dissolved organic matter (DOM) in surface waters was developed and applied to samples from Illinois lakes. Isolation of the acidic (humic) DOM fraction was optimized using solutions of simple model compounds chemically similar to humics and commercially available soil humic acid. Recoveries of DOM from five humic-containing (colored) surface waters were in excess of 90%. A series of experiments using model compounds, various desorption solutions, and select charge modified and unmodified cellulose separation materials demonstrated that the mechanism of sorption of the acidic fraction, and of its recovery by controlled desorption, is simple ion exchange. Hydrophobic (nonpolar) interactions did not affect sorption processes as has been suggested by other authors. Subsequently, filtered water samples were applied to a fractionation scheme designed to separate the DOM into anion exchanged (acidic), cation exchanged (basic) and nonexchanged (neutral) fractions. Of the DOM, most of the dissolved organic carbon and a large portion of dissolved organic nitrogen (DON) in all samples was recovered in the acidic fraction, with the neutral fraction containing most of the remaining DOM. The cationic (at pH 3) fraction contained a lower portion of the DOM than expected, indicating that DON in the water samples was not composed of positively charged amines available for ion exchange under the experimental conditions. DON was monitored throughout the fractionation scheme by a sensitive fluorescence (o-phthaldialdehyde) method developed in this study and generally applicable to measuring small samples containing low concentrations of DON found in natural waters. The lack of suitable methods for isolating and concentrating dissolved organic matter has hindered progress on its chemical characterization. The fractionation scheme developed and tested is a useful tool for researchers studying the chemical nature of dissolved organic matter, which affects water quality in many ways.

Publisher

University of Illinois at Urbana-Champaign. Water Resources Center

Series/Report Name or Number

• Water Resources Center Research Report no. 190
• ISWS Reprint Series 0642

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/90361

Sponsor(s)/Grant Number(s)

• U.S. Department of the Interior
• U.S. Geological Survey

Copyright and License Information

Copyright 1984 held by John R. Tuschall, Jr.,Gregory George

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