OUTLINES

CHROMATOGRAPHY HISTORY GAS CHROMATOGRAPHY GAS CHROMATOGRAPH MAIN COMPONENTS WORKING PRINCIPLE OF GC PROCEDURE OF GC FACTORS AFFECTING GC

•Greek word “CHROMA” and “Graphein”.

•Process of separation and analyzation of complex mixture

It works on the basis of rate at which the types of components flow. As the mixture of various components enter the chromatograph we will observe that the different components of a mixture move/flow at different rate. This different rate of flowing is responsible for the separation of their components.

Mikhail Tswett

Russian Botanist(1872-1919)

John MartinBritish chemist

1910-2002

Gas chromatography is separation method.

Gas chromatography is a chromatographic technique that can be used to separate volatile organic compounds.

Gas Chromatography consists of two phases.

Mobile Phase Stationary phase

GAS CHROMATOGRAPH MAIN

COMPONENETS:

Carrier GasInjection PortColumnOvenDetectorSample

This is the mobile phase and should be inert gas(he, ar etc)

INJECTION PORT

The injection port consist of rubber septum through which a syringe needle is inserted to inject the sample.

COLUMN

Column is the most important component where separation takes place.

OVEN

Oven is also an important component in which column is fitted.

DETECTOR

Detector is to indicate the presence and measure the amount of component eluted out from the column.

SAMPLE

The mixture of components which is to be analyzed.

WORKING PRINCIPLE OF

GC It works on the principle that the organic compounds are separated due to differences in their partitioning behavior between Mobile phase and Stationary phase.

The mobile phase is comprised of inert gas.The stationary phase consists of packed column.

PROCEDURE OF

GC Sample is injected in column. Oven heats the system to vaporize the sample and speed its passage through the column. The different components of the sample will be separated by the column because each of the components “sticks” to the liquid coating that on the column packing differently.

When a substance leaves the column, it is sensed by a detector. The detector generates the voltage that is proportional to the amount of the substance.

Chromatogram

Temperature: T he higher the temperature, the more of the compound is in the gas phase.

Carrier gas flow: If the carrier gas flow is high, the molecules do not have a chance to interact with the stationary phase.

Column length: The longer the column is the better the separation usually is.

Amount of material injected: The injection of too much sample causes poor separation.

Conclusion: High temperatures and high flow rates decrease the retention time, but also deteriorate the quality of the separation.

PRESENTED BY:

ALLAH WARAYO (12PG41) NOOR MUHAMMAD (12PG37)ABDUL KARIM (12PG34)

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