1)Gas chromatography known as Gc is most common type of Chromatography which is used in Analytic chemistry for analysing chemicalscompounds that can be vapourised wihtout decomposition through seperations.
2)It can be used to included testing the purity of a particular substance or seperation of different mixture of components along with the relative amount.GC can be used to prepare pure compound from relative mixyure also.
3)In gas chromatography, the mobile phase (or "moving phase") is a carrier gas, usuallycalled as an inert gas such as helium or such as nitrogen which is unreactive gas. In stationary phase requires a microscopic layer of liquid or polymer on an inert solid support, inside a piece of glass or metal tubing called a column (a homage to the fractionating column used in distillation). The instrument that perform gas chromatography is called a gas chromatograph (or "aerograph", "gas separator").
3) Gas chromatography is a same principal to column of chromatography (as well as other forms of chromatography, such as HPLC, TLC), but has several differences.
Process for seperating.
A) Firstly, the process of separating the compounds in a mixture is carried out between a liquid stationary phase and a gas mobile phase, whereas in column chromatography the stationary phase is a solid and the mobile phase is a liquid. (Hence the full name of the procedure is "Gas-liquid chromatography", referring to the mobile and stationary phases, respectively.) .
B) Secondly, the column through which the gas phase passes is located in an oven where temperature of the gas can be controlled, whereas column chromatography (typically) has no such control on temperature.
C) Thirdly, the Concentration of a compound in the gas phase is solely a
function of the Vapor-pressure of the Gas.
D) Gas chromatography is also same as to fractional distillation, Both processes separate the components of a mixture primarily based on Boiling point (or vapor pressure) differences. However, fractional distillation is typically used to separate components of a mixture on a large scale, whereas GC can be used on a much smaller scale (i.e. microscale).
E) In a GC analysis, a known volume of gaseous or liquid analytes which is injected into the "Entrance" (head) of the column, usually using a MicroSyringe ( or a gas source switching system). As the carrier gas sweeps the analytes molecules through the column, this motion is stopped by the Adsorption of the analytic molecules either onto the column walls or onto packing materials in the column. The rate at which the molecules progress along the column depends on the strength of adsorption, which in turn depends on the type of molecule and on stationary phase materials. Since each type of molecule has a different rate of progression, the various components of the analytic mixture are separated as they progress along the column and reach the end of the column at different times (Retention -time). A Detector is used to monitor the outlet stream from the column thus,the time at which each components reached the outlets and the amount of that components can be determined. Generally, substances are identified (qualitatively) by the order in which they Emerged ) from the column and by the Retention-time of the analytic in the column.