Modification of the van den Berg/Ruzic method for the investigation of complexation parameters of natural waters

A modified version of the van den Berg/Ruzic transformation method for the determination of metal complexation parameters from voltammetric data is described and tested. The modification relieves the normal requirement that the sensitivity (S) of the voltammetric technique be accurately known before the transformation is applied. Using computer simulations in which experimental uncertainty is included, an iterative technique for the indirect determination of S from experimental data was developed. The technique avoids the need to fully saturate ligands in order to determine S accurately and so overcomes an experimental difficulty of the conventional van den Berg/Ruzic method. The improvement in the determination of complexation parameters is demonstrated using both computer simulations and experimental data obtained using ethylenediaminetetraacetic acid (EDTA) as a model ligand.