Variations in transition metal ion speciation due to differences in dissolved organic matter

CHED 1158

Richard James Wienhold, richard.wienhold@mnsu.edu and John D. Thoemke, john.thoemke@mnsu.edu. Department of Chemistry and Geology, Minnesota State University, Mankato, 242 Trafton Science Center North, Mankato, MN 56001
We explore the interaction of dissolved organic matter (DOM) and transition metal ions. We use the competing ligand exchange method with Chelex resin to determine the binding kinetics of several natural waters and several transition metals. Then, using the kinetics data we attempt to correlate variations in the DOM binding with the characteristics of the DOM excitation-emission fluorescence spectra. The competing ligand exchange results suggest that dissolved organic matter with a strong terrestrial component releases the metal ion at a faster rate.