SPECTROFLUOROMETRIC INVESTIGATION OF TRACE-METAL COMPLEXATION BY AN AQUEOUS CHESTNUT LEAF LITTER EXTRACT

Fluorescence spectroscopy was investigated as a method for quantitating trace metal complexes with the organic ligands in a water extract of chestnut (Castanea sativa L. ) leaf litter. Copper(II) and aluminum(III) were selected as environmentally significant metals with which to characterize the method as applied to the leaf litter extract. Solutions of Cu or Al mixed with the extract exhibited fluorescence that decreased in relative intensity as the total metal concentration and/or the pH increased. Data were obtained in the pH range 5 to 8 for total Cu concentrations up to 160 mmol m** minus **3 and in the pH range 4 to 8 for total Al concentrations up to 100 mmol m** minus . The fluorescence intensity data for Cu were comparable to those obtained in previous studies for solutions of Cu and soluble humic materials. A conventional equation was used to calculate an overall stability coefficient for metal complexation by the leaf litter extract. The pH-dependence of this stability coefficient was modeled mathematically.