Theory of zone shape for isoelectric focusing in a tapered capillary

The factors determining the position and the width of the focused zone in the tapered capillary, where the applied longitudinal electric current causes the temperature gradients and related pH gradients, are analyzed. The optimal conditions for this thermal isoelectric focusing at the initial stage of the research are formulated. These conditions include limitations for the temperature, the electric current and the electroosmotic flow in the tapered capillary. Further, the possibilities of more sophisticated selection of the system parameters are discussed, when a mutual compensation of the factors, 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.