(Contributor: Johann Bauer, Max-Planck Institute Martinsried, Germany)
Free Flow Electrophoresis (FFE) is an electrophoresis procedure working continuously in the absence of a stationary phase (or solid support material such as a gel). It separates preparatively charged particles ranging in size from molecular to cellular dimensions according to their electrophoretic mobilities (EPMs) or isoelectric points (pIs). Samples are injected continuously into a thin buffer film, which may be segmented or uniform, flowing through a chamber formed by two narrowly spaced glass plates. Perpendicularly to the electrolyte and sample flow, current may be applied while the fluid is flowing (continuous FFE) or while the fluid flow is transiently stopped (interval FFE). In any case the applied electric field leads to movement of charged sample components towards the respective counterelectrode according to their electrophoretic mobilities or isoelectric points. The sample and the electrolyte used for a separation enter the separation chamber at one end and the electrolyte containing different sample components as separated bands is fractionated at the other side.
|FFE-mode||samples for separation||resolution*||throughput*|
|zone electrophoresis (ZE)||cells, bacteria, proteins, peptides, (DNA), viruses, membranes, organelles, enantiomers||3% EPM||40 Mio/h**
|isoelectric focusing (IEF)||proteins, peptides, membranes, organelles, viruses||0.03 pI||500 mg/h***|
|isotachophoresis (ITP)||proteins, peptides, membranes, organelles, (bacteria), viruses, enantiomers||1% EPM||150 mg/h***|
|field step electrophoresis (FSE)||preconditioning of any sample||30% EPM||5 g/h***|