Size‐Exclusion Chromatography in Single and Mixed Eluents: Effects of Sorption of Solvent and Polymer Solutes on Novel TSK‐Gel Super AW Columns

Abstract

The novel TSK Gel Super AW column packing is based on a polymeric gel with residual hydrophobic and hydrophilic groups on the gel surface. These groups can act as active sites making the chromatographic support compatible both with polar and apolar eluents. This interesting property allows the elution of systems of very different polarities but also induces binary polymer–gel, polymer–solvent, and solvent–gel enthalpic interactions that lead to a mixture of separation mechanisms: repulsion, partition, or adsorption besides the main size‐exclusion chromatography (SEC) mechanism. For this reason, the elution behaviour of many and diverse polymer/solvent systems has been studied in these columns. Depending on the chemical nature of the polymeric solutes and/or the thermodynamic quality of the eluents (pure and mixed solvents), the universal calibration curves deviate from that of a reference system, which is supposed to elute according to an ideal SEC mechanism. The observed deviations have been qualitative and quantitatively explained in terms of the predominant binary interactions, and therefore, in the light of the secondary mechanisms present in the separation process.

Keywords:

• Size‐exclusion chromatography
• Calibration curves
• Pure and mixed eluents
• Secondary effects

Acknowledgments

Financial support from Ministerio de Ciencia y Tecnología (Spain) under Grant No. MAT2003‐00668 is gratefully acknowledged.