Chromatography Flashcards
What is the mobile phase?
Where soluble components of the mixture are carried
What is the stationary phase?
Holds back certain components of the mixture that are attracted to the phase
Why is chromatography used?
To separate and identify the different components in a mixture
How do samples change their speed in the mobile and stationary phases?
Mobile = components with more affinity to the solvent move faster
Stationary = higher affinity to this phase means components move slower
How do you calculate the Rf value?
Rf = distance moved by spot / distance moved by solvent
What is TLC?
Thin Layer Chromatography:
Plate is coated with a solid and a solvent moves up the plate
What are the advantages of using a TLC?
+ runs faster
+ smaller amounts of mixture can be separated
+ more robust than paper
What is column chromatography?
Column is packed with a solid and a solvent moves down the column
Stationary phase = silica
Mobile = solvent
What are the advantages of column chromatography?
+ more than one solvent can be used
+ large amounts can be separated
What is gas-liquid chromatography (GLC)?
Column is packed with a solid / solid coated by liquid
Gas is passed through column under pressure at high temperature
What are the advantages of GLC?
+ very sensitive
+ detects minute traces
