Pulsed-field gel electrophoresis (PFGE), or clamped homogeneous electrical field electrophoresis (CHEF), is a novel gel electrophoresis type for the separation of DNA macromolecules.
This is accomplished by alternating anode and cathode at specific intervals, which means that the DNA molecules have to realign themselves in the electrical field before they can continue to progress in the matrix.
Smaller molecules orient themselves much faster than larger ones, which means that they cover a larger distance in a predetermined amount of time. The separation of the DNA molecules relies on a series of various factors: voltage, runtime, buffer concentration, temperature and how fast anode and cathode are changing.