A new method for rapid and high sensitivity determinations of low-molecular-weight organic acids in seawater

University Of Connecticut, Storrs CT

Investigators

Abstract

Low-molecular-weight (LMW) organic acids are key compounds in organic matter degradation and production in marine environments; however, few studies have been carried out on the cycling of these compounds in seawater mostly because the needed methodology with sufficiently low detection limits is not available. Also, existing techniques require extensive sample handling and manipulation, and have high blanks, resulting in high detection limits. Researchers from the University of Connecticut plan to develop a new method for determining LMW organic acid concentrations in seawater and sediment pore water by tagging highly fluorescent coumarin derivatives via an amide bond. They will test multiple methods for conjugating the coumarin to the acid in aqueous neutral or mildly acidic solutions to identify one with the highest efficiency combined with the lowest chemical blank. Great care will be taken in the selection and preparation of solvents and reagents to minimize contamination with formate or acetate. The scientists will also develop and validate HPLC protocols to separate and quantify a large range of LMW organic acid coumarin amides using fluorescence detection and implement the derivatization as a semi-automated on-line method, thereby significantly shortening the work-up time per sample and further decreasing contamination problems. This research would provide the science community with a new analytical method to further our knowledge of the cycling of LMW organic acids in seawater. The co-PI (Christian Brueckner) would continue to participate in the annual Junior Science and Humanities Symposium held at the University of Connecticut Department of Chemistry, an event that provides high school students and teachers with an opportunity to carry out hands-on science experiments. Two graduate and two undergraduate students would be supported and trained as part of this project.