Distribution processes of inorganic solutes in gel chromatography

Mechanism of ion stacking in aqueous partition chromatographic processes

“…The effect of the background ions in solution on the distribution of the analyte ion is represented according to Eqs. and , which also indicates that the retention of an ionic solute on a column packed with a nonionic material can rationally be interpreted with the ion partition model .…”

“…However, the D values of the ions strongly depend on the type of the coexisting counterion and coion as shown in Table . These counterion and coion effects cannot be explained by the size‐exclusion effect . The order of the D values for ions is not determined by the sizes of the hydrated ions but by their relative solubility in the interfacial water at the hydrophobic surface and in the bulk water .…”

“…Separation of metal ions and simple anions by various types of hydrophilic polymer gels, that is, cross‐linked dextran, polyacrylamide gels, etc. has been studied since the 1960s . It has also been shown in recent years that even hydrophobic materials such as polystyrene resin and octadecyl bonded silica exhibit selective ion separation.…”

“…Shibukawa et al [ demonstrated that the separation of ionic compounds observed not only on hydrophilic polymer gel columns but also on the columns packed with hydrophobic materials can be interpreted successfully with the partition between the bulk water and the water incorporated in the polymer matrices on the basis of a stoichiometric ion partition model. They also showed that the amount of water in a polymer gel that exhibits different affinity to solute compounds from the bulk water and functions as the stationary phase can be estimated by a liquid chromatographic method .…”

Partition/Ion-Exclusion Chromatographic Ion Stacking for the Analysis of Trace Anions in Water and Salt Samples by Ion Chromatography

“…This ion-stacking phenomenon takes place due to the effect of the background co-ion in the eluant and/or sample solution on the distribution of the ions between the bulk water and the water incorporated in the packing material, which acts as the stationary phase. [24][25][26][27][28][29][30][31] Furthermore, we have succeeded in accumulating analyte anions having distribution coefficients larger than that of the component anion of the added electrolyte in a very narrow zone at the trailing edge of the elution band of the electrolyte using ion-exclusion effect exerted by fixed anionic charges on a hydrophilic polymer packing material as well as partition chromatographic ion stacking. 23 It was shown that the enrichment factor as high as several hundred for some inorganic anions could be achieved with a hydrophilic polymer column of 300 mm long.…”