Band broadening in high-performance liquid chromatographic separations of enantiomers with swollen microcrystalline cellulose triacetate packings: II. Influence of eluent composition, temperature and pressure

Abstract

The peak dispersion in high-performance liquid chromatographic columns packed with swollen crystalline cellulose triacetate was investigated as a function of the eluent composition, the temperature and the pressure. The results provide support for a model which assumes the existence of at least two types of adsorption sites, “quick”-type and “slow”-type sites, which differ with respect to the rate of the adsorption/desorption process. The observed dependence of the peak dispersion on the temperature and the eluent composition can be understood as resulting from three factors: (i) changes in the diffusion velocity by changes in the solvent viscosity; (ii) changes in the three-dimensional structure of the adsorbent due to changes in the swelling state of the CTA adsorbent and (iii) changes in the availability and accessibility of the adsorption sites due to differences in the strength of the competitive adsorption of the solvent components.