Description and detection of moving sample zones in zone electrophoresis: zone spreading due to the sample as a necessary discontinuous element

Abstract

This paper deals with the description and detection of moving sample zones in free zone electrophoresis. It is shown that the shape of a sample zone never reaches a steady-state. However, either the front or the rear boundary of the sample zones, but not both, can represent steady-state concentration distributions with decreasing peak heights. This results in an unsymmetrical broadening of the moving zones. With a multichannel detection device, consisting of 255 equidistant detectors along the separation trough, asymmetric electric field distributions of the sample components are measured. These are shown to agree with theoretical predictions, made by a model based on migration only. This clarifies the fact that in zone electrophoresis migrational dispersion due to the applied electric field is usually much larger than diffusional spreading.