Question

Lab #2: Gas Chromatography Theory behind gas chromatography What do all types of chromatography share in common? Relationship between retention time and boiling point/vapor pressure How changing parameters affect the retention time Ramp rate Temperature Length of column Pressure Whether column is packed or unpacked

Answer 1

. Gas Chromatography → H is a process of separating componentes) from the given oude drug by wring a gaseous mobile phase o + gi involves a sample berat being vaporized and infected onto the head of chromato. - graphic colarmni. o is the sample is transported through the column by the flow of ineart gaseous mobile phase, . The column itself have a liquid stationary phase which is adsorbed onto the susface of inent solid Two major types Gas- solid chromatography- Here, the mobile phase is a gas, while the stationary phase is a solid :) Gas- liquid chromatography The mobile phase is a gas while the stationary phase is a liquid retained on the surface as an inert solid by adsorption of chemical bonding,

The principle of separation in gas. Chromatography is la partition's : The mixture of component to be separed by is convented to vapour and mixed with : galeous mobile phase Common things in all type. Chromatography s. There is always a mobile and a stationary phase in all types of chromatography, Structure of a chromatograph is always basically like Transport system. ) Sample application 1) Column iv). defector v). Plotting uniti y all types of chromatography is used for separation and identification of component mixtures

Relationship between refention time and bolling point .. Retention time is inversely propertional to Boiling point i If a component has a low Bp., the it is likely to spend more time to the gas. phase. Thereforce, its retension finge will be lower than a compound with a higher boiling point is - Parameters affecting the retention Time - - :) Ramp Rate - Ramp rate can affect a retention time shift of all the peaks. - Refention time increases with a lowes. initial tempe, But it is for inversely propeshonal to romp rate ne longer the initial hold time, Slower is the ramp riate. b) Temperature - Temperature is inversely propertional to retention time,

A high column temp. will give shorten retention time, as more components stay in the gas phase but this can result in poo separation. - c) length of column A longer column will produce longes, retention times but better separation. So, length of the column is directly propertional to the retention time. d) Pressure. . . - Pressure is directly propertional to retention time. in Retention time is normal with fresh of column and normal pressure but as pressure increases with some sample injections, the retension time stast to Increase e) Packing of column - Much thinnen wall packed column can give strength by they are most flexible a packed colums contain a finely divided, inert, solid support metal coated with liquid stationary phase.