8. Separating Molecules



  • used to separate stuff in a mixture
  • once separated you can identify the components
  • it can separate out and identify biological molecules e.g. amino acids, carbohydrates, vitamins and nucleic acids
  • there are different types- thin layer and paper chromotography

How does it work?

  • a mobile phase- where the molecules can move, this is a liquid solvent, such as ethanol or water
  • a stationery phase- where the molecules can't move. in paper chromatography this is a piece of chromatography paper. in thin layer this is a thin layer of solid (0.1-0.3mm thick) e.g. silica gel, on a glass plate.
  • they all use the same basic principle:
    • the mobile phase moves through/ on the stationary phase
    • the components spend different amounts of time in the mobile and stationery phase
    • the components that spend longer…


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