Hyphenated thermal field flow fractionation--capillary electrophoresis

The possibility was considered to use the transverse thermophoresis of analytes in the capillary for capillary electrophoresis (CE) to control the separation process, decrease the peak width due to thermal effects and provide new separation parameters in CE. As the examination has shown, in non-aqueous buffers the Joule heating in the capillary for CE can provide transverse temperature gradients comparable with the temperature gradients in conventional devices for thermal field flow Fractionation (ThFFF). It was proposed to use the non-uniform velocity profile of analytes caused by the transverse temperature gradient and the temperature dependence of the buffer viscosity for the FFF-like separation of analytes besides CE separation. The expressions for the peak parameters have been derived, where the non-uniform transverse analyte concentration distribution due to the thermophoresis is taken into account, and the possibilities based on FFF-CE principles are discussed. As possible objects of this hyphenated technique, macromolecules and particles are considered.