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 What is paper and gas chromatography? It is not explained in this lesson, why?

Paper chromatography is a method chemists use to separate compounds from one another on the basis of retention factor (Rf). Those compounds which are slowly adsorbed have low retention factor and moves to less upward direction.  While the compound of higher retention factor moves to upward direction highly.

The RF is a ratio of the distance the "spot" travels relative to the distance the solvent (water in this case) travels. The RF is calculated by dividing the "spot" distance by the solvent distance.

http://0.tqn.com/d/chemistry/1/0/_/V/paperchrom.jpg

Gas Chromatography: In gas chromatography, the mobile phase is a gas that is moved through the column, while the stationary phase is a liquid film that coats the column filling (in packed columns) or the column wall (in capillary columns). Hence, the correct name for gas chromatography is "Gas Liquid Chromatography", abbreviated GLC. Compounds are injected onto the column and carried through it by the mobile phase; depending on their partition into the stationary phase, they move slower or faster. A sensitive detector is required at the end of the column to detect and quantify the compounds as they leave the column.

http://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Gas_chromatograph.png/350px-Gas_chromatograph.png

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Paper chromatography

Paper chromatography is a technique that involves placing a small dot or line of sample solution onto a strip of chromatography paper. The paper is placed in a jar containing a shallow layer of solvent and sealed. As the solvent rises through the paper, it meets the sample mixture which starts to travel up the paper with the solvent. This paper is made of cellulose, a polar substance, and the compounds within the mixture travel farther if they are non-polar. More polar substances bond with the cellulose paper more quickly, and therefore do not travel as far.

Gas chromatography

Gas chromatography (GC), also sometimes known as Gas-Liquid chromatography, (GLC), is a separation technique in which the mobile phase is a gas. Gas chromatography is always carried out in a column, which is typically "packed" or "capillary" (see below) .

Gas chromatography (GC) is based on a partition equillibrium of analyte between a solid stationary phase (often a liquid silicone-based material) and a mobile gas (most often Helium). The stationary phase is adhered to the inside of a small-diameter glass tube (a capillary column) or a solid matrix inside a larger metal tube (a packed column). It is widely used in analytical chemistry; though the high temperatures used in GC make it unsuitable for high molecular weight biopolymers or proteins (heat will denature them), frequently encountered in biochemistry, it is well suited for use in the petrochemical, environmental monitoring and remediation, and industrial chemical fields. It is also used extensively in chemistry research.

it is not in our syllabus, so just have a watch.., dont study it deeply... :)

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