Gas Chromatography Essay

What is Gas Chromatography?

Gas Chromatography also known as vapor-phase chromatography (VPC), or gas–liquid partition chromatography (GLPC) is most widely used analytical technique in the world; it is used for the separating and analysing compounds that can be vaporized without decomposing. Among its uses are being able to test the purity of a substance, being able to separate different components in a mixture and help in environmental contaminant identification . This can lead to GC being able to help identify an unknown compounds. The goal purpose of GC is to separate the mixtures into individual components that can be detected and measured one at a time. A plot of the detector output is called a chromatogram, which charts the detector’s response as a function of time, showing the separate components

All chromatography involves the stationary phase and the mobile phase. After injection of a mixture, separation is achieved in the capillary column. This column is coated with a fluid or a solid support, the stationary phase The carrier gas (mobile phase) propels the sample down the column where the separation process occurs. The use of flow meters and pressure gauges are helpful to maintain constant gas flow. As the carrier gas plays an important role it is best that it is dry, free of oxygen and that it does not react with the sample or column. There are different types of columns used packed columns and capillary columns; the capillary is more commonly used as a only a small sample is need and it analyses faster. This will be essential to produce strong and accurate results. Hydrogen (H) generally is a good carrier gas but; it may react and convert the sample into another substance. The choice of carrier gas may hinge on the ...

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(Taken from http://en.wikipedia.org/wiki/File:Ethanol-2D-flat.png)

In conclusion Gas Chromatography has many uses to separate and analyse compounds and to be able find separate components in a mixture to identify any unknown components. Because of it's simplicity and effectiveness it is one of the most important tools to chemistry. Like most analytical techniques it has its advantages such as not being harmful to the sample be used and disadvantages such as not being particularly use with liquids that change temperate easily.

References http://www.justchromatography.com/chromatography/gc http://chemwiki.ucdavis.edu/Analytical_Chemistry/Instrumental_Analysis/Chromatography/Gas_Chromatography#Sample_Injection http://www.scientific.org/tutorials/articles/gcms.html http://www.innovationservices.philips.com/sites/default/files/materials-analysis-gcms.pdf