A critical analysis of analytical procedures for the study of copper in the presence of natural organic ligands

The presence of copper is ambiguous within the aqueous environment. Total concentration depends solely on inputs from natural sources and enhanced through anthropogenic sources. It is not the total concentration of copper in the system that is of environmental concern, but rather the activity of the free, uncomplexed copper present. Available ligands, both organic and inorganic, may interact with copper resulting in one of two possible scenarios: restricting the amount of available copper for such processes as biological uptake and nourishment or regulating copper concentrations in excess of biological tolerance.; This study focuses on the ability of prevailing analytical methods to study the interaction between copper and natural organic matter (NOM). Because it is important to determine results that are accurate and precise, each aspect of the experiment must not bias the results, where biased results would render interpretation useless.; The first part of this research investigates the means in which the pH is controlled, arguably the most influential parameter controlling an environmental system. Several zwitterionic pH buffers popular in both biochemical and environmental studies were evaluated to determine their binding characteristics with copper.; The next section of this study investigates two popular electroanalytical techniques used to determine copper complexation with NOM. Both potentiometry and voltammetry are applied to study copper binding characteristics in the presence of NOM. Potentiometry was investigated using a copper solid-state ion selective electrode. Competitive ligand exchange-absorption cathodic stripping voltammetry was used to collaborate the results from potentiometry. Copper complexation with NOM should be related to the bulk properties of the NOM.; The objectives for this research were to (1) determine appropriate pH buffers for use in copper binding studies, (2) evaluate the copper jalpaite ion-selective electrode for use in the presence and absence of strong ligands, (3) compare electroanalytical methods for determining Cu 2+ in the presence of natural organic ligands and (4) spectroscopically characterize a series of natural organic ligands for comparison with their copper binding properties.