Abstract: A method for determining the hydrodynamic radius for the constituents of an admixture, includes: (A) by separating capillary electrophoresis, the constituents of the admixture, leaving them within the capillary; (B) at one of the ends of the capillary obtained in this manner, containing, in different zones, the separated constituents, a detectable marker is injected in the region of a detection device which is placed at the side of the other end of the capillary; (C) a pressure difference is induced between the ends of the capillary in order to cause the various constituents separated in step (A) and finally the marker to migrate towards the outlet of the capillary; and (D) by analyzing the Taylor dispersion produced in step (C), the hydrodynamic radius is determined for each of the constituents, based on the detection time of the marker and the elution profile of each of the constituents.

Abstract: A method for separating the constituents of a mixture M by electrophoresis in a single capillary includes (A) separating compounds of the mixture M in a single capillary according to the capillary electrophoresis technique; (B) isolating a fraction F of the compounds thus separated by evacuating part of the compounds having the highest migration speeds from the capillary and/or evacuating part of the compounds having the lowest migration speeds from the capillary; (C) introducing a separating medium MS having a higher migration speed than the compounds of the isolated fraction F into the capillary containing the isolated fraction F, and (D) the compounds contained in fraction F are separated in the new electrophoretic conditions thus obtained.