Electrophoresis

Electrophoretic separations are based upon the fact that the electrical force (F) on a charged particle (ion) in an electrical field (E) is proportional to the charge of the particle (q), or F = qE (Eq 1).

The migration of the charged particle in the electric field, called the electrophoretic mobility (μ), is defined as μ = v/E = q/f (Eq 2), where v is the velocity of the charged particle and f is a complex term called the frictional coefficient. The frictional coefficient relates to the size and the shape of the particle. From equation (2) it can be seen that electrophoretic mobility decreases for larger particles and increases with higher charge.