Ion Exclusion Chromatography: Model Development and Experimental Evaluation

Abstract

Ion exclusion chromatography (IEC) is a separation technique used both at analytical scale for the simultaneous determination of ionic species and at preparative scale for the separation of strong electrolytes from weak electrolytes and nonelectrolytes. In this work, a column model for IEC is developed and evaluated by comparison with experimental data. The model explicitly takes into account the Donnan equilibria responsible for the exclusion of electrolytes from the resin pores. At the high electrolytes concentrations typical of preparative scale separations, resin shrinking becomes an important factor, affecting the variation of inter-and intraparticle void fractions. The effect of the electrolytes concentration on resin shrinking has been experimentally studied, and the volumes variation was included in the model equations. At the analytical scale, the proposed model is able to predict the effect of electrolytes concentration on the extent of exclusion from the resin pores and the influence of the degree of dissociation of weak electrolytes on their retention time. At preparative conditions, discrepancies between the experimental data and simulations results are observed for divalent salts. Since such discrepancies arise at the largest concentrations, they have been imputed to the main model assumption of ideal thermodynamics.

Paliperidone–Cation Exchange Resin Complexes of Different Particle Sizes for Controlled Release

“…Moreover, the CERs (AmberLite TM IRP69, DIAION TM UBK530, and AmberLite TM IRP69F) in this study possess the structural sulfonate functional group, which is almost completely ionized regardless of solution pH. The pKa of piperadine in PPD was 8.3 and it was ionizable in 0.1 N HCl solution (pH 1.2) used for PCC formation [ 26 , 33 , 34 ].…”

Solution- and gas-phase behavior of decavanadate: implications for mass spectrometric analysis of redox-active polyoxidometalates

“…IEC is a mixed-mode chromatographic modality, in which differential exclusion of weak electrolytes from the anionic resin pores is used as a physical principle enabling analyte separation. 33 Although in the past IEC has been applied almost exclusively to separation of weak organic acids (based on their sizes and p K a values 34 ), it can be used for separation of inorganic anions as well. 35,36 Since V10, as well as many smaller vanadates, are weak acids, we hypothesized that it may be possible to achieve their retention on IEC.…”

In situ product recovery techniques aiming to obtain biotechnological products: A glance to current knowledge

“…The operational costs of the distillation and fractionation operations required on an industrial scale are relatively high, and this is the process step that demands the highest amount of energy due to the low concentrations of the product in the medium. Thus, more viable alternatives such as the use of stripping gas technologies have been studied [37,38]. Volatile compounds can be partially removed using a gas phase, such as isoprene, some monoterpenes, and short‐chain fatty acids, in a bioreactor [39].…”