Using Fluorescence and Absorption Spectroscopy to Characterize High Performapce Liquid Chromatography Fractionated CDOM from West Florida Rivers

The chemical and optical properties of colored dissolved organic matter (CDOM) have been the subject of numerous studies. However, this material has not been characterized to the point at which it can be identified by compound or compound class. The complex and homogenous nature of this material makes characterization studies challenging. CDOM absorbs ultraviolet and visible radiation and is highly photo reactive. The purpose of this study is to investigate the optical properties of fractions separated by reversed-phase high-performance liquid chromatography (HPLC) as well as the simple fractionation that occurs during the concentration and extraction of CDOM by C1s SEP-PAK. The focus of this study is the characterization of CDOM in the Suwannee and Manatee Rivers in western Florida. These rivers are a major source of CDOM to the Eastern Gulf of Mexico, which is a river-dominated environment. HPLC fractions were collected for the Suwannee River using reversed-phase HPLC and elution gradient. CDOM optical properties vary greatly with chemical composition and source. Although HPLC does allow for separation of organic material according to polarity, the complexity of the material persisted. Few major differences were identified among the HPLC fractions of Suwannee River CDOM. However differences between rivers and the simple fractions resulting from the concentration and extraction procedure indicate that further HPLC study used in addition to other separation methods may provide insights into the relationship between chemical and optical properties