Potentiometric studies of some lanthanide glycollate systems

Abstract

Precise potentiometric titrations have been carried out on a number of lanthanide glycollate systems, using a technique which avoids junction potentials and the changes in glass electrode asymmetry potential due to replacement of cell contents following the calibration of the cell. Values of ligand to metal ratios were insufficiently high to give reliable determinations of the formation constants of the third and fourth complex species, and an attrition technique was adopted to ensure the reliability of the first two stability constants. Two computational methods were employed, and the sensitivity of the results to the method chosen gives warning of the need for careful design of experiments and for appropriate choice of computational method in such multi-complex systems.