Combined thermal field-flow fractionation–capillary electrophoresis

Abstract

The possibility of using the transverse thermophoresis of analytes in the capillary used in capillary electrophoresis (CE) to control the separation process was considered, thus decreasing the spreading of the thermal peak and providing new separation parameters in CE. The Joule heating in non-aqueous buffers in the CE capillary can provide transverse temperature gradients comparable to temperature gradients in conventional equipment for thermal field-flow fractionation (ThFFF). It is proposed to use the non-uniform velocity profile of analytes caused by transverse temperature gradient and the temperature dependence of the buffer viscosity for the FFF-like separation of analytes in addition to CE separation. The expressions for the peak parameters are derived, taking into account the non-uniform transverse analyte distribution due to the thermophoresis, and the possibilities based on FFF–CE principles are discussed. As possible objects of this hyphenated technique, macromolecules and particles are considered.