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What is the mobile phase in paper chromatography?
solvent
What is the stationary phase in paper chromatography?
Absorbent paper
If a stronger affinity for mobile phase ...
moves quickly
If a stronger affinity for the stationary phase ...
moves slowly
What is the stationary phase in column chromatography?
SiO2/Al2O3 powder
What is the mobile phase in column chromatography?
Solvent
What is the stationary phase in TLC chromatography?
SiO2/Al2O3 powder on glass/plastic plate
What is the mobile phase in TLC chromatography?
Solvent
What is the stationary phase in Gas chromatography?
SiO2/Al2O3 powder
What is the mobile phase in Gas chromatography?
Inert gas
What is the solvent used for the mobile phase called?
Eluent
Give an example of a non-polar solvent
Alkanes
Give examples of polar solvents
Water, alcohols
What are the advantages of TLC chromatography?
Smaller amounts of mixtures can be separated
Plates are more robust than paper
What can TLC chromatography be used for?
Colourless samples
Results can be viewed using UV light
What is a benefit of using ninhydrin when analysing amino acid using TLC chromatography?
Don't need UV light to see samples
How is RF calculated?
distance moved by spot/distance moved by solvent
What is an advantage of using Column chromatography?
Can use large amounts
What kinds of liquids would use Gas chromatography?
Volatile liquids
What is the retention time?
Time taken to travel through the tube
What is the process?
Long coiled tube packed with powder
Inert gas passed through tube
Sample analysed by mass spec
Why does separation occur in chromatography?
Different substances have different polarities and different relative affinities for the stationary and mobile phase
What factors affect the Rf value in TLC chromatography?
Temperature
solvent
What factors affect the retention time in column chromatography?
Length of column
temperature
Solvent
How does column chromatography work?
glass column is packed silica/alumina
mixture to be separated is added to the top of the column
solvent is added to top of column and continuously run through
Different substances leave the column at different times and can be collected in different flasks at the bottom
What is the key measurement in gas and column chromatography?
Retention time
What factors affect the retention time in gas chromatography?
Length of column
Temperature
Gas pressure
Give an example of an inert gas used for gas chromatography
Hydrogen
