Selective Isolation of Dissolved Organic Matter from Aquatic Systems

摘要

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. Recoveries of DOM from five humic-containing (colored) surface waters were in excess of 90%. A series of experiments using model compounds 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. Filtered water samples were applied to a fractionation scheme 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.