How to classify the Electrophoresis

Electrophoresis is working on the basic principle of migration of charged particles under the influence of electric field. The electrophoresis are mainly TWO types of electrophoresis,

1)  Free Electrophoresis (or) Electrophoresis without stabilizing media
2)  Zone Electrophoresis (or) Electrophoresis in Stabilizing media 
 

1) Free Electrophoresis:
In this Electrophoresis, Stabilizing media (Agar, Starch, Polyacrylamide)is not using. It has TWO main techniques:
 
A)  Micro electrophoresis:
 
It  involves  the  observation  of  motion  of  small  particles  in  an  electric  field  with  a microscope. In modern days this technique is applied only for measuring the Zeta Potentials of cell such as RBCs, Neutrophils and Bacteria etc.

What is this, I want more? See the Details-

• Micro electrophoresis is the best-known method for determination of zeta potentials of fiber fines and filler particles in paper machine white water.
• The apparatus includes a capillary cell, two chambers that include electrodes, and a means of observing the motion of particles. Because the capillary diameter is usually smaller than the length of a cellulosic fiber, these may be removed by filtration through a screen before the test.
• The apparatus is filled with very dilute suspension and the chambers are closed. A direct-current voltage is applied between electrodes in the respective chambers.
• One uses a microscope to determine the velocity of particles.
• The ratio or the velocity to the electrical field strength is known as the electrophoretic mobility.
• By making reasonable assumptions about the size of the observed particles and the electrical conductivity it is possible to calculate the value of the zeta potential.
• Zeta potential values near to zero indicate that the particles in the mixture are likely to stick together when they collide, unless they also are stabilized by non-electrical factors.
• Particles having a negative zeta potential are expected to interact strongly with cationic additives.

Read More: What are the factors affecting on Electrophoretic methods

B)  Moving Boundary Electrophoresis (m.b.e.):
 
The  technique  was  first  developed  by  A.Tiselius  of SWEDEN  in  the  1937.  this technique  is  conducting  in  U-shaped  observation  cell.  It  is  very  popular  for  quantitative analysis of complex mixtures of macromolecules, especially Proteins.

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• Moving-boundary electrophoresis or free-boundary electrophoresis is electrophoresis in a free solution. It was developed by Arne Tiselius in 1937.
• Tiselius was awarded the 1948 Nobel Prize in chemistry for his work on the separation of colloids through electrophoresis, the motion of charged particles through a stationary liquid under the influence of an electric field.
• The apparatus includes a U-shaped cell filled with buffer solution and electrodes immersed at its ends.
• The sample applied could be any mixture of charged components like a protein mixture.
• On applying voltage, the compounds will migrate to the anode or cathode depending on their charges.
• The change in the refractive index at the boundary of the separated compounds is detected using Schlieren optics at both ends of the solution in the cell.

2) Zone Electrophoresis: 
 
KONIG published  the  first  experiment  on  the  use  of filter  paper  as  a  stabilizing  medium  in electrophoresis.  In  this,  several  stabilizing  media  are  using  like  Agar,  Starch  &  Polyacrylamide.  In  this, “Microlitres” of sample can also analyze.

General techniques of Zone Electrophoresis:

1. Paper Electrophoresis
2. SDS-PAGE
3. Iso-electric focusing

Read More: Electrophoresis principle, types, Procedures and Applications.