Electrophoresis is a physical method of analysis which
involves separation of the compounds that are capable
of acquiring electric charge in conducting electrodes.
Electrophoresis may be defined as the migration of the
charged particle through a solution under the influence of an
Ions that are suspended between two electrodes tends
to travel towards the electrodes that bears opposite
3. Zone Electrophoresis
c)Thin Layer Electrophoresis
d)Cellulose acetate Electrophoresis
Moving Boundary Electrophoresis
a) Capillary Electrophoresis
c) Isoelectric Focusing
d) Immuno Electrophoresis
4. It involves the migration of the charged
particle on the supporting media.
Paper, Cellulose acetate membrane, Starch
Gel, Poly acrylamide.
Components separated are distributed into
discrete zone on the support media.
Supporting media is saturated with buffer
solution, small volume of the sample is
applied as narrow band.
6. Separation is brought about through molecular sieving
technique, basedonthe molecularsize of the substances.
Gel material acts as a "molecular sieve”.
Gel is a colloid in a solid form (99 is water).
It is important that the support media is electrically neutral.
Different types of gels which can be used are; Agar
A porous gel acts as a sieve by retarding or, in some
cases, by completely obstructing the movement of
macromolecules while allowing smaller molecules to
7. It is prepared by polymerizing acryl amide monomers in the
methylene-bis-acrylamide to cross link the
Structure of acrylamide (CH2=CH-CO-NH2)
Polyacrylamide gel structure held together by covalent cross-links.
Polyacrylamide gels are tougherthan agarosegels.
It is thermostable,transparent, strong and relatively chemically inert.
Gels are uncharged and are prepared in a variety of pore sizes.
Proteins are separated on the basis of charge to mass ratio
and molecularsize, a phenomenon called Molecularsieving.
Gels are stable over wide range of pH and temperature.
Gels of different pore size can be formed.
Simple and separation speed is good comparatively.
8. SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis, is a
technique widely used in biochemistry, forensics, genetics and molecular
biology to separate proteinsaccordingto their electrophoreticmobility.
When a detergent SDS added to PAGE the combined procedure is termed
as SDS PAGE.
SDS coats protein molecules giving all proteins a constant charge-mass
Due to masking of charges of proteins by the large negative charge on SDS
binding with them, the proteins migrate along the gel in order of increasing
SDS is an anionic detergent which denatures secondary and non–disulfide–
linked tertiary structures by wrapping around the polypeptide backbone. In so
doing, SDS confers a net negative charge to the polypeptide in proportion to
Molecules in solution with SDS have a net negative charge within a wide pH
A polypeptide chain binds amounts of SDS in proportion to its relative
The negative charges on SDS destroy most of the complex structure of
proteins, and are strongly attracted toward an anode in an electric field.
9. Studies can be carried out in thin layer of
Less time consuming and goodresolution.
Widely used in combinedelectrophoretic-
chromatographystudies in two dimensional study
of proteins and nucleic acid hydrolysates
10. The principle behind electrophoresis is that charged molecules will migrate toward the
opposite pole and separate from each other based on physical characteristics.
Capillary electrophoresis has grown to become a collection of a range of separation
techniques which involve the application of high voltages across buffer filled capillaries to
achieve separations .
Capillary electrophoresis, then, is the technique of performing electrophoresis in buffer
filled, narrow-borecapillaries, normally from 25 to 100 mmin internal diameter (ID).
A highvoltage (typically 10-30 kV) is applied.
Capillaries are typically of 50 µminner diameter and 0.5 to 1 min length.
Due to electro osmotic flow, all sample components migrate towards the negative
The capillary can also be filled with a gel, which eliminates the electro osmotic flow.
Separation is accomplished as in conventional gel electrophoresis but the capillary
allows higherresolution, greater sensitivity, andon-linedetection.
The capillary is filled with electrolyte solution which conducts current through the inside
of the capillary. The ends of the capillary are dipped into reservoirs filled with the
Electrodes(platinum)are inserted into the electrolyte reservoirs to completethe
1) As spreading of bands is minimized due to application of the
applied field and the PH gradient , high resolution can be
2) Proteins that differ by as little as 0.001 PH units can be
1) Because carrier ampholytes are generally used in high
concentration, a high voltage (upto 2000v ) is necessary . As a
result the electrophoretic matrix must be cooled which sometimes
makes it difficult.
1) For separating proteinsandpeptides.
2) For research in enzymology, immunology,cytologyand
12. DNA Sequencing
Separation of organic acid, alkaloids, carbohydrates,aminoacids,alcohols, phenols, nucleicacids,
In food industry
It is employed in biochemicalandclinicalfieldsi.e. in the study of protein mixtures such as blood
serum, hemoglobin and in the study of antigen- antibody interactions.
Electrophoresis in combination with autoradiography is used to study the bindingof ironto serum
Used for analysis of Terpenoids,steroidsandantibiotics.
For testing purity of thyroid hormonesby zone electrophoresis.
Paper chromato-electrophoresis is used to separate free Insulinfrom plasma proteins.
It is used for diagnosisof various diseases of kidney,liver andCVS.
It is also used for separation of ScopolamineandEphedrineusingbufferat PH4.2.
Electrophoresis is also used for separation of carbohydratesandvitamins.
Quantitative separation of all fractions of cellular entities, antibiotics, RBC,Enzymesetc ispossible