its all about chromatography

1. TO
STUDY
CHROMATOGRAPHY
BY:- Kamlesh Yadav
(Msc.Medical Biochemistry)

2. INTRODUCTION
 Chromatography literally means colour writing.
 It was first employed by Russian Scientist
Mikhail Tswett in 1906.
 It is a technique that separates the components of
a mixed sample with the help of two immiscible
phases which move relative to each other and
differ in ratio of their affinities for different
components of sample with which both are in
contact.

3. PRINCIPLE
 One of the phases participating in the separation
is known as the mobile phase, which consists of
a liquid/gas moving through another phase
known as stationary phase which is immobile
consisting of solid beads or liquid immobilized
on these particles.
 According to the ratio of affinities for two phases
the individual components of the sample migrate
over different distances with mobile phase
passing through stationary phase and thus get
separated from each other along the course of
mobile phase.

4. CONTINUED...
 Components with higher affinities for mobile
phase move further than those with higher
affinities for stationary phase.

5. CLASSIFICATION
 Chromatographic methods are often
classified by nature of interaction between
sample components and stationary phase
whereby the components are retarded to
different degrees in their migration along with
mobile phase and are consistently separated
from each other.

6. MAJOR TYPES OF CHROMATOGRAPHY
 Partition chromatography
e.g. Paper, Gas-Liquid Chromatography, Thin
layer chromatography.
 Adsorption chromatography
 Ion exchange chromatography
 Molecular sieve or gel filtration
 Affinity chromatography
 High performance liquid
chromatography(HPLC)

7. PAPER CHROMATOGRAPHY
 It is a form of liquid-liquid or partition
chromatography.
 In paper chromatography, a few drops of
solution containing a mixture of the compounds
to be separated is applied at 2cm above, a strip
of filter paper.
 The paper is dried and dipped in to a solvent
mixture consisting of Butanol, Acetic acid and
Water in 4:1:5 ratio.
 The aqueous component of solvent forms the
stationary phase where as organic component
forms the mobile phase.

8.  The rate of migration of the molecules depends
on the relative solubilities in the stationary phase
and the mobile phase.
 After a sufficient migration of the solvent front,
the paper (chromatogram) is removed, dried and
developed for the identification of the specific
spots.
 Ninhydrin, which forms purple complex with α-
amino acids, is frequently used as a colouring
reagent.
 The migration of a substance is frequently
expressed as Rf value (ratio of fronts)
 Rf =

9.  It is very easy, simple, rapid and highly
efficient method of separation which can be
applied to even microgram quantities of the
sample.
 It is very useful for separating amino acids,
oligopeptides, sugar, oligosaccharides,
glycosides, purines, pyrimidines, steroids,
vitamins and some antibiotics like penicillin,
streptomycin, tetracycline.

11. THIN LAYER CHROMATOGRAPHY
 In thin layer chromatography, in place of paper
an inert substance, such as cellulose, is
employed as supporting material.
 Cellulose is spread as a thin layer (0.25-2.0 mm
thick) on glass or plastic plates.
 In case of adsorption thin layer chromatography,
adsorbents such as activated silica gel, alumina
are used.
 This is a very rapid method with high power of
resolution for separating fatty acids, steroids,
sugars, amino acids, oligopeptides, nucleotides,
alkaloids and athletic doping drugs.

13. GEL FILTRATION CHROMATOGRAPHY:
(MOLECULAR SEIVE OR MOLECULAR EXCLUSION )
 In gel filtration chromatography, the separation
of molecules is based on their shape, size and
molecular weight.
 The apparatus consists of a column packed with
sponge like gel beads containing pores.
 The solution mixture containing molecules of
different sizes are applied to column and eluted
with a buffer,
 The larger molecules cannot pass through the
pores of the gel and therefore, move faster
whereas the smaller molecules enter the gel
beads and are left behind which come out
slowly.

14.  This column chromatography method separates
ribosome, viruses, nucleic acids and protein
molecules depending upon the particle size and
shape. This is very effective in isolating.
IgM from other classes of Ig.
Light and heavy chains of Igs.
Bence Jones proteins in multiple myeloma
patients.
 It is also used widely for determining molecular
weight of proteins.

16. AFFINITY CHROMATOGRAPHY
 It is a form of column chromatography which isolates
a biologically active protein molecule depending
upon its affinity for binding non covalently to specific
molecules known as ligands. E.g., enzymes,
antibodies, nucleic acids, vitamins and drugs.
 The principle of affinity chromatography is based on
the specific and noncovalent binding of substances-
like proteins and enzymes to a specific ligand (e.g.
cofactor or substrates) which is attached to the gel
matrix,e.g. separation of lactate dehydrogenase from
RBC using NAD+ cofactor as a ligand which is linked
to a affinity gel.

17.  An ideal matrix for affinity chromatography should be
stable during binding of the macromolecule and its
subsequent elution.
 The chemical nature of the ligand is dictated by the
biological specificity of the compound to be purified.
E.g., 5AMP which can bind reversibly to many NAD+
dependent dehydrogenases because it is structurally
similar to part of the NAD+ molecule.
 Once the sample has been applied and the
macromolecule bound, the column is eluted with
buffer ( the buffer used must contain any cofactors,
such as metal ions, necessary for ligand-
macromolecule interaction) to remove non-specifically
bound contaminants.

19. ION-EXCHANGE CHROMATOGRAPHY
 Ion-exchange chromatography involves the
separation of molecules on the basis of their
electrical charges.
 Ion-exchange resins - cations exchangers and
anion exchangers- are used for this purpose.
 This is a form of column chromatography for
separation of proteins, peptides, amino acids,
nucleic acids, nucleotides and sugars
depending upon their acid base properties and
electric charges.
 Used in measurement of HbA1c, porphyrin &
water purification.

21. GAS CHROMATOGRAPHY
 In gas chromatography the mobile phase is an inert
gas, usually nitrogen which passes through a column
containing the stationary phase.
 Separation occurs by the distribution of the mixture in
vapour phase between carrier gas and the stationary
phase.
 Different physical processes occuring on the
stationary phase effect separation and include
adsorption, partition and molecular sieve effects.
 The terms, gas-solid chromatography (GSC) and gas-
liquid chromatography (GLC), refer to the nature of
the stationary phase which is a solid alone (GSC) or a
liquid distributed on the surface of a solid (GLC).

22. HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
(HPLC)
 This is a rapid automated method for
partition, adsorption, ion exchange and
molecular sieve chromatography.
 The high performance of liquid
chromatography is achieved by a
considerable increase in column efficiency by
using packing materials of small particle size
(5 to20 µm).
 A fully automated HPLC system (Bio Rad
Variant) is used to separate and determine
hemoglobin A2, hemoglobin F,D,S,C and E
and also glycosylated hemoglobin.

24. FAST PROTEIN LIQUID CHROMATOGRAPHY
 There are no unique principles associated with FPLC, it is
simply based on reversed phase, affinity, exclusion,
hydrophobic interaction and ion-exchange chromatography,
and chromatofocussing.
 In FPLC the mobile phase is an aqueous solution, or “buffer”.
The buffer flow rate is controlled by a positive-displacement
pump and is normally kept constant, while the composition of
the buffer can be varied by drawing fluids in different
proportions from two or more external reservoirs. The
stationary phase is a resin composed of beads, usually of
cross-linked agarose, packed into a cylindrical glass or plastic
column.
 In the most common FPLC strategy, ion exchange, a resin is
chosen so that the protein of interest will bind to the resin by a
charge interaction while in buffer A (the running buffer) but

25.  A mixture containing one or more proteins of interest is
dissolved in 100% buffer A and pumped into the column.
The proteins of interest bind to the resin while other
components are carried out in the buffer.
 The total flow rate of the buffer is kept constant; however,
the proportion of Buffer B (the “elution” buffer) is gradually
increased from 0% to 100% according to a programmed
change in concentration (the “gradient”).
 At some point during this process each of the bound
proteins dissociates and appears in the effluent.
 The effluent passes through two detectors which measure
salt concentration (by conductivity) and protein
concentration(by absorption of ultraviolet light at a
wavelength of 280nm).
 As each protein is eluted it appears in the effluent as a