Theory of zone shape for isoelectric focusing in a tapered capillary

The factors determining the position and the width of the focused zone in t he tapered capillary, where the applied longitudinal electric current cause s the temperature gradients and related pH gradients, are analyzed. The opt imal conditions for this thermal isoelectric focusing at the initial stage of the research are formulated. These conditions include limitations for th e temperature, the electric current and the electroosmotic flow in the tape red capillary. Further, the possibilities of more sophisticated selection o f the system parameters are discussed, when a mutual compensation of the fa ctors, which shift and spread the focused zone, may be used. This situation may be used for the isoelectric focusing process with a higher efficiency and for the wider separation parameters range.