<unk>  is the movement of an electrically charged substance under the influence of an electric field. This movement is due to the Coulomb force, which may be related to fundamental electrical properties of the body under study and the ambient electrical conditions by the equation given below. F is the Coulomb force, q is the charge carried by the body, E is the electric field:
The resulting electrophoretic migration is countered by forces of friction such that the rate of migration is constant in a constant and homogeneous electric field:
Where v is the velocity and f is the frictional coefficient.
The electrophoretic mobility 
μ
{\displaystyle \mu }
 is defined as followed.
The expression above applied only to ions at a concentration approaching 0 and in a non-conductive solvent. Polyionic molecules are surrounded by a cloud of counterions which alter the effective electric field applied on the ions to be separated. This renders the previous expression a poor approximation of what really happens in an electrophoretic apparatus.
The mobility depends on both the particle properties (e.g., surface charge density and size) and solution properties (e.g., ionic strength, electric permittivity, and pH).  For high ionic strengths, an approximate expression for the electrophoretic mobility (m².V/s) is given by the Smoluchowski equation,
where 
ϵ
{\displaystyle \epsilon }
 is the dielectric constant of the liquid (–), 
ϵ
0
{\displaystyle \epsilon _{0}}
 is the permittivity of free space (C².N.m-2), 
η
{\displaystyle \eta }
 is the viscosity of the liquid (Pa.s), and 
ζ
{\displaystyle \zeta }
 is the zeta potential (i.e., the electrokinetic potential, taken as equal to the surface potential) of the particle (V).
Electrophoresis
Dot blot
Native PAGE
Enzyme assay
Counterimmunoelectrophoresis
Nucleic acid hybridization
SDS-PAGE
Western blot