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This video describes the principle of column chromatography. It is also called column adsorption chromatography. it describes the separation of various components present in the mixture based on the difference in its affinity towards the stationary phase and mobile phase.. It explains the different packing methods with its advantages and disadvantages. Dry packing and wet packing methods are described. The various fractions are collected and analysed. The uncoloured samples are visualised using thin layer chromatography (TLC). The applications of this technique used is explained.
Column adsorption chromatography
Column adsorption chromatography is a technique used to physically separate the components/compounds present in a mixture by the difference in their affinity towards the stationary phase and the mobile phase.
Columns - to support the stationary phase/adsorbent such as silica gel or alumina
Size of the column depends on
Type of adsorbent
Number of components present
Affinity of components towards the adsorbent
Quantity of the sample
Best results - narrow longer columns better than short thicker columns - more plates to separate
Stationary phase - adsorbent such as silica gel or alumina
Dry packing - dry silica is packed and solvent is poured until silica is wet and settled
Bubbles/voids can be entrapped
Wet packing - slurry of silica mixed with solvent is poured into the column
Adsorbent settles uniformly without any cracks
Mobile phase - solvent/mixture of solvents - cyclohexane, ether, acetone, benzene etc.
Its function:
As a solvent - to dissolve the sample comprising of mixture of compounds
As a developing agent - to separate the components from the mixture
As an eluent - to elute the separated components (removes pure compound).
Advantages of Column chromatography/ Column adsorption chromatography
Simple analysis
Any type of mixture can be separated
Does not require more space
Wide choice of mobile phase
Disadvantages of Column chromatography/ Column adsorption chromatography
More solvent is required
Time consuming
Packing of column requires skill
Applications of Column chromatography/ Column adsorption chromatography
Pharmaceutical industries - presence of drugs in extracts or formulations.
Organic compounds and biochemical - separation of impurities from the main
Medicinal biochemistry - isolation and purification of drugs and hormones etc.
compounds, separation of compounds from mixture etc.
Medicinal biochemistry - isolation and purification of drugs and hormones etc.