CHARACTERIZATION OF FEAT FULVIC-ACID FRACTIONS BY MEANS OF FT-IR, SERS, AND H-1, C-13 NMR-SPECTROSCOPY

Fourier transform infrared (FT-IR), surface-enhanced Raman spectroscop y (SERS), and nuclear magnetic resonance (NMR) (H-1 and C-13) have bee n applied to the characterization of unfractionated and fractionated f ulvic acids extracted from an Irish peat. Raman study of these compoun ds is possible on rough metallic surfaces, which enhance the Raman sig nal and quench the high fluorescence. The application of these spectro scopic techniques has provided important structural information concer ning the aromaticity and the carboxylate and carbohydrate group conten ts in each fraction. In addition, a SERS study at different pH levels has revealed interesting interfacial behavior of these components base d on electric charge and conformational changes.