Analysis of Titration Curves of Lake Tjeukemeer Water With Cu(II). Identification of the Formation of More than Two Groups of Different Complexes

The results for direct titration of Lake Tjeukemeer water with Cu(II) are interpreted by using both the van den Berg-Ružić and Scatchard plots. The use of a new method for correction of asymptote at higher additions of metal proposed by Ružić and Pečar has been illustrated with these titration data. The analysis of reduced titration data obtained by extraction of the equation for weaker complexes from the original titration data has been proved to be a very powerful method by which the accuracy of determining com- plexation parameters for higher energy binding sites can be checked. The following stability constants (Kfi and complexing capacities CL,-) are reported. High concentration of organic matter in the Lake enabled direct titration with Cu(II) in a wide range of concentrations, so that four different binding strengths could be detected from the titration data.