Fluorescence quenching method for determining equilibrium constants for polycyclic aromatic hydrocarbons binding to dissolved humic materials

✍ Scribed by Gauthier, Thomas D.; Shane, Edward C.; Guerin, William F.; Seitz, W. Rudolf.; Grant, Clarence L.

• Book ID: 111938463
• Publisher: American Chemical Society
• Year: 1986
• Tongue: English
• Weight: 705 KB
• Volume: 20
• Category: Article
• ISSN: 0013-936X
• DOI: 10.1021/es00153a012

✦ Synopsis

rn A fluorescence quenching method has been developed for determining equilibrium constants for the association of pyrene, phenanthrene, and anthracene with dissolved humic and fulvic acids. The technique is based upon the observation that polycyclic aromatic hydrocarbon (PAH) fluorescence in aqueous solution is quenched upon association with humic material. Association constants are derived from the fractional decrease in fluorescence intensity as a function of added humic material with Stern-Volmer plots. This allows association constants to be measured without a separation. In addition, the technique involves a ratio measurement so the exact concentration of pollutant need not be determined. Stern-Volmer plots were linear for the three PAHs studied. Anthracene-humic association constants determined by the fluorescence quenching technique correlated reasonably well with values determined by a reverse-phase method. However, unlike the reverse-phase method the measured association constants do not depend on the concentration of dissolved organic matter.