A technique used to separate a mixture into different substances.
Below you can see a chromatogram:
- Draw the origin line in pencil (starting point)
- The solution is spotted onto the origin
- Paper is suspended in a tank of solvent and left
- The final place where the solvent reaches is marked the solvent front
Identifying the mixture:
- Measure the distance from the origin to the middle of the spot
- Measure the distance from the origin to the solvent front
- We identify the spots using an Rf value, Rf = distance travelled by spot/distance travelled by solvent
- Then compare your value to one in the table – Rf values are always less than 1!!!! If it is higher you have done something wrong!!!!