Learning objectives


spotted plate
 
 
fully developed
Chromatography is a group of techniques used to separate mixtures.  The mixture is dissolved in a suitable solvent, and the solution is applied to an inert substance (stationary phase).
 
In thin-layer chromatography the stationary phase is a layer of silica on an aluminium-backed plate. 

The diagram shows a thin layer plate where a mixture has been applied at the left side and a pure substance at the right.

The mixture is separated by passing a mobile phase (solvent) over the stationary phase.
 
The diagram shows the result.

This activity is concerned with aspects of thin-layer chromatography.  After completion of the activity, you should be able to
 
  • describe how and where the plate is spotted
  • describe how the the separation is done
  • describe why the separation occurs
  • calculate the Retardation Factor (Rf) for a particular spot
Dr Sheila Woodgate
© The University of Auckland 2002