Compiler Basics

The term chromatography literally means color writing, and denotes a method by which the substance to be analysed is put into a vertical tube containing an adsorbent, the various parts of the substance moving through the adsorbent at varied rates of speed, according to their degree of attraction to it, produce bands of color at different levels of the adsorption column.

This is done in two phases, the mobile phase which is refered to the fluid that carries the mixture of substances in the sample through the adsorptive material and the stationary or adsorbent phase which is a solid material that takes up the particles of the substance passing through it.

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3.5.1 Techniques involved in Chromatography

The technique is a valuable tool for the research biochemist and is readily adaptable to investigations conducted in the clinical laboratory. For example, chromatography is used to detect and identify in body fluids, certain sugars and amino acids associated with inborn errors of metabolism.

1. Adsorption Chromatography: that in which the stationary phase is an adsorbent.

2. Affinity Chromatography: that based on a highly specific biologic interaction such as that between antigen and antibody, enzyme and substrate, or receptor and ligand.

3. Column Chromatography: the technique in which the various solutes of a solution are allowed to travel down a column, the individual components being adsorbed by the stationary phase. The most strongly adsorbed component will remain near the top of the column; the other components will pass to positions farther and farther down the column according to their affinity for the adsorbent.

4. Exclusion Chromatography: that in which the stationary phase is a gel having a closely controlled pore size. Molecules are separated based on molecular size and shape, smaller molecules being temporarily retained in the pores.

5. Gas Chromatography: a type of automated chromatography in which the mobile phase is an inert gas. Volatile components of the sample are separated in the column and measured by a detector. The method has been applied in the clinical laboratory to separate and quantify steroids, barbiturates, and lipids.

6. Gas-Liquid chromatography: gas chromatography in which the substances to be separated are moved by an inert gas along a tube filled with a finely divided inert solid coated with a nonvolatile oil;

each component migrates at a rate determined by its solubility in oil and its vapor pressure.

7. Ion Exchange chromatography: that utilizing ion exchange RESINS, to which are coupled either cations or anions that will exchange with other cations or anions in the material passed through their meshwork.

8. Paper Chromatography: a form of chromatography in which a sheet of blotting paper, usually filter paper, is substituted for the adsorption column. After separation of the components as a consequence of their differential migratory velocities, they are stained to make the chromatogram visible. In the clinical laboratory, paper chromatography is employed to detect and identify sugars and amino acids.

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9. Partition Chromatography: a process of separation of solutes utilizing the partition of the solutes between two liquid phases, namely the original solvent and the film of solvent on the adsorption column.

10. Thin-Layer Chromatography: that in which the stationary phase is a thin layer of an adsorbent such as silica gel coated on a flat plate. It is otherwise similar to paper chromatography.

3.5.2 Application of Chromatography

This t technique is widely applied in various fields, few of which is the manufacturing plant – to purify a chemical needed to make a product. Biotechnology industry:

establishing the purity or concentration of compounds in biotechnological research.

Biological application – Chromatography has many applications in biology. It is used to separate and identify amino acids, carbohydrates, fatty acids, and other natural substances.

4.0 CONCLUSION

Separation techniques are an important part of chemistry. However, their importance is not just limited to chemistry; they are also used in our daily lives. Separation techniques are methods used to separate and or purify mixtures. There are many kinds of separation techniques that are used in our daily life; Crystallisation, Filtration, Distillation etc

Separation methods are processes that involve the separation of chemical mixtures that are crucially important in many areas of analyses. There are as many uses for separation as there are techniques to accomplish it, as well as their applications in various fields of research

5.0 SUMMARY

In this unit, you have learnt the various separation techniques, their principles as well as their applications. These techniques include:

1. Filtration 2. Extraction 3. Distillation

4. Crystallisation and 5. Chromatography.