ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: macca69831 on March 13, 2010, 01:27:14 pm
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1) What are the differences between Paper Chromatography and Thin Layer Chromatography?
2) What are the differences between Paper Chromatography and Gas Chromatography?
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1) In paper chromatography you use paper whilst in TLC you would use glass or silica coated with something like alumina as the stationary phase.
2) The stationary phase for gas chromatography is porous solid (a very small solid coated with a liquid) and the mobile phase is gas. The component being tested is injected into the gas chromatograph as a gaseous form. A detector used for gas chromatography unlike paper.
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paper chromatogrpahy is paper and TLC uses a thin layer of substance like aliminum oxide powder and the same process occurs.
Paper chromotagpahy talks about Rf value whilst gas chromatogpahy talks about the retention time. paper involves soluble substances whilst gas one invovles gas :S in gas c an oven is used to insatntly evaporate the substances to gas.
correct me if i'm wrong
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How does TLC separate the components of a mixture?
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Stationary phase = usually polar , ie. silica
So the mobile phase , if the compound being studied is polar ( so forming h bonds with silica ) , it will adsorb more to the stationary phase, therefore won't much of a distance up the plate, and the non polar components who will not adsorb much to the silica stationary phase, will move further distance up the plate.
Also the size of the component can determine the separation. Therefore, larger the component, less distance it will move up the plate and vice versa.
Hope that helped.
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Thanks for the detailed description of how it works. Do you, by any chance, know anything about the GC from https://cianalytics.com/technology/gas-chromatography ?