Systematic interpretation of the anion-exchange behaviour of polyphosphate oligomers

Anion-exchange distribution ratio of some linear and cyclo-polyphosphate oligomers were measured in tetramethylammonium chloride solution using Dowex 1-X4 anion-exchange resin. The selectivity coefficient K-Cl(p), of the exchange reaction was evaluated from the log D vs, log([Cl-]/<([Cl-])over bar>) plot for each polyphosphate anion. The dependence of selectivity coefficient on the charge of the anion is interpreted in terms of the structure of the phosphate species. Differences in selectivity coefficients between the linear and cyclo-polyphosphate series are also discussed. (C) 1998 Elsevier Science B.V. All rights reserved.