DETERMINATION OF COPPER SPECIATION IN MARINE WATERS BY COMPETITIVE LIGAND EQUILIBRATION LIQUID-LIQUID-EXTRACTION - AN EVALUATION OF THE TECHNIQUE

A technique for determining organic complexation of copper using a com petitive ligand equilibration coupled with liquid-liquid extraction wa s evaluated with respect to its applicability in marine waters. Partic ular attention was paid to the equilibration times required, extractab ility of naturally occurring organic copper complexes, and consistency with results from electrochemical techniques. In general, it was foun d that although this approach produces results that agree well with th ose from other analyses of the open ocean, there are unresolved discre pancies when it is applied to copper analyses in estuarine samples. Th e ability to use the technique for analysis of a single sample at diff erent competition strengths, or analytical windows, was also examined. In open ocean waters, it was possible to identify two discrete ligand classes with three different windows, although the determined extent of binding did increase with increasing competition strength.