High temperature and temperature programming in capillary electrochromatography

In electrochromatography, solvent electrophoretic mobility and solute parti tioning are temperature dependent processes. If temperature variations are controlled, solute selectivity and analysis times can be tailored. In this study the feasibility of temperature programming in capillary electrochroma tography (CEC) was demonstrated using a reversed-phase CEC mode. The outcom e of programmed separations was compared with isothermal, isocratic and iso rheic (constant flow) separations. The combined effects of column temperatu re and mobile phase flow-rate changes during the separation run, resulted i n up to a 50% reduction in the separation run time, without adversely affec ting the quality of separation. For capillary electrochromatography, temper ature programming may be a valuable alternative to solvent programming mode s because of the great technical difficulties associated with carrying out solvent gradient elution. (C) 2000 Elsevier Science BN. All rights reserved .