Learning Objectives are 1. To understand classification of chromatography 2. To learn Thin Layer Chromatography(TLC), Principle and technique for TLC. 3. To demonstrate the steps for performing TLC 4. To understand the applications of TLC

2. Learning Objectives
• Learning Objectives are
1. to understand classification of chromatography
2. To learn Thin Layer Chromatography(TLC),
Principle and technique for TLC.
3. To demonstrate the steps for performing TLC
4. To understand the applications of TLC

3. Classification of Chromatography

5. Adsorption Chromatography:
Definition:
The analytical
separation of a chemical
mixture (gas or liquid) by
passing it over an adsorbent
bed that adsorbs different
compounds at different rates.
• The stationary phase in
adsorption Chromatography is
called "Adsorbent"

6. Adsorbent??
• A solid which has the property of
holding the molecules at its surface
particularly when it is porous and
finely devided.
• Commonly used:
• silica gel and alumina,
• others are charcoal and
polyamides.

7. Principle:
• In adsorption chromatogrphy,
small differences in sorption and
desorption behaviour of
substances between moving
solvents and the stationary phase
are utilize to achieve separation.

9. Definition:
• In TLC a thin layer of a solid
stationary phase (usually silica gel) is
used while mobile phase is liquid.

10. Technique:
• Following steps are involved:
• 1) Preparation of TLC plate:
20x5 cm glass plates.
Silica gel is spread
uniformly.
Dried at room temperature.
In oven at 110°C
Pre coated TLC plates are also

11. TLC
2) Application of sample to TLC
plate:
3) Choice of solvent
4) Placement of TLC plate in
chromatographic jar:

12. 5)Drying of TLC plate:
6)Location of substance on TLC plate:
i- Ordinary light.
ii- U-V light.
iii- Iodine vapors.
iv- Detecting or spraying reagents.

13. Calculation of Rf-value:
• Rf value is calculated as:
Rf=Distance traveled by substance
distance travelled by solvent

14. Applications:
For separation and
identification of: amino acids,
alkaloids, anti-biotic and
vitamins
It is used to detect pesticide or
insecticide residues in food
used in forensic science to detect
a Poison in blood sample of a
person.

15. Reading Material
• P.D. Sethi, Identification of Drugs in Pharmaceutical
Formulations by Thin Layer chromatography, CBS Publisher
& Distributors P Ltd; 2nd edition, 2010.
• Hildebert Wagner, Plant Drug Analysis: A Thin Layer
Chromatography Atlas, 2nd edition, Springer-Verlag, New
York, 2007.
• Tyler V.E., Brady E.R. and Robbers J.E. Pharmacognosy, 9th
ed., Lea & Febiger, Philadelphia