Collaborative Research: Analysis of Metal Chelators in Marine Systems by HPLC with Derivatization

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

ABSTRACT OCE-0002538 Almost all biologically active trace metal cations in seawater are complexed by organic ligands, and complexation is believed to exert an important influence on the geochemistry and biological availability of these elements, many of which are critical micronutrients. However, there is little, if any, information on the structures of these compounds, or any definitive information on sources and sinks, though biological sources have been inferred on the basis of their distributions and binding characteristics. Some researchers have been successful in isolating and identifying chelators produced by cultures of marine bacteria and phytoplankton, namely Fe siderophores and phytochelatins that strongly complex Cu. In this study, the PIs will develop sensitive assays for Fe and Cu chelators using liquid chromatography coupled to a selection of highly promising derivatization schemes to measure these compounds directly in seawater at nanomolar levels. This is a novel approach, based on the observation that many of these ligands contain functional groups that form analytically useful adducts with derivatizing agents that can be separated from other materials. The objective of the research is to determine if these compounds are important ligands in seawater, and the assays will serve as a basis for modified protocols to look for structurally similar compounds. The long term goals of the project is to develop useful analytical protocols that will be used widely in the field to answer questions about the factors that control metal complexation in seawater, and their relationship to ecosystem-scale processes.