A NEW METHOD FOR DATA-ANALYSIS IN STUDIES OF TRACE-METAL COMPLEXATION

A new method for correction of the asymptote at high additions of trac e metal during titration was developed for the van den Berg-Ruzic plot . Using this method, a more accurate value for complexing capacity can be obtained from titration data. The accuracy of this parameter is a limiting factor for detailed studies of trace metal complexation in na tural waters. In addition, a sequential analysis of the shape of titra tion curves is proposed, by which more than two different groups of co mplexes can be identified in the case of a large ratio between the com plexing capacity and trace metal concentration originally present in t he water sample. These procedures are illustrated by the analysis of s ynthetic titration curves for two and three groups of different comple xes. The complexation parameters were reproduced with satisfactory acc uracy in both cases. Simultaneous use of both the van den Berg-Ruzic a nd Scatchard plots is suggested in order to test the agreement between the experimental titration data and theoretical predictions based on the complexation parameters determined.