ANALYSIS OF THE RATE OF DISSOCIATION OF LIGAND COMPLEXES

Copper-humate dissociation data using humic material from different sa mpling points in the Ogeechee River (Georgia, USA) as measured by Olso n et al. are re-analyzed with the newly developed LODA-G2 method for t he determination of rate constant distribution functions. The LODA-G2 method is based on an approximation of the local decay function. A smo othing spline procedure is applied to the data in order to account for the experimental error. The appropriate smoothing parameter is obtain ed on the basis of the generalized cross-validation technique adapted to the present problem. Without data treatment, spurious peaks occur i n the distribution functions due to the experimental error. With the p resent analysis not only the rate constant distribution function but a lso its confidence interval is found. By considering the confidence in tervals, overinterpretation of the results can be excluded. The result s obtained are similar to those of Olson et al., indicating that the i ntuitive smoothing applied by these authors was fairly realistic. The practical implications of the distribution functions found are briefly discussed.