4.3.1 CHROMATOGRAPHY

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What is chromatography?
an analytical technique that supersets components in a mixture between a mobile phase and a stationary phase
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Describe thin layer chromatography (TLC)
stationary phase is solid/ mobile phase liquid/ separation by absorption
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Describe gas chromatography
stationary phase can be solid or liquid/ mobile phase is gas/ separation by adsorption or solubility
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Describe the mobile phase of chromatography
liquid or gas
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What does a solid stationary phase separate by?
adsorption
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What does a liquid stationary phase separate by?
solubility
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How do you calculate an Rf value?
distance travelled by spot/ distance travelled by solvent
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Define retention time
the time taken from the injection of a sample to the moment when a substance is detected in gas chromatography
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Outline how to read a chromatogram
retention time is from 0 to centre of peak/ area under each peak is the relative amount of each component present/ retention times can be found in a ref table
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What are the limitations of gas chromatography analysis?
similar compounds often have similar retention times/ unknown compounds have no reference retention times for comparison
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Why is GC and MS sometimes combined?
far more powerful analytical tool/ GC i good at separating a mixture but not great at identifying and MC i every good at identifying unknown compounds
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Explain how GC-MS works
sample separated using GC/ separating components fed into a MC/ the spectrometer produces a mass spec for each component/ whole process can be automated with PCs
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What are the uses of GC-MS?
forensics (crime scenes etc.)/ airport security/ space probes/ environmental analysis (detect and track pollutants etc.)
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Other cards in this set

Card 2

Front

Describe thin layer chromatography (TLC)

Back

stationary phase is solid/ mobile phase liquid/ separation by absorption

Card 3

Front

Describe gas chromatography

Back

Preview of the front of card 3

Card 4

Front

Describe the mobile phase of chromatography

Back

Preview of the front of card 4

Card 5

Front

What does a solid stationary phase separate by?

Back

Preview of the front of card 5
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