Chromatography

• Chromatography is a method to separate and identify components from a mixture of soluble substances
• Stationary phase:

  • Starting point where molecules can't move on the chromatography paper
  • Can be a solid or a really thick ink
• Mobile phase:

  • Solvent in which the sample can move
  • Solvent moves along the chromatography paper based on the size of the molecules at different rates of movement
• Paper chromatogram:

  • Used to distinguish between pure and impure substances
  • Pure substances produce one spot on the chromatogram
  • Impure substances separate, producing two or more spots
• Rf value:

  • Ratio of the solute's distance travelled to the solvent's distance travelled
  • Ranges between 0 and 1
• Reference values:

  • Known substances used for comparison with unknown substances
  • Rf values of reference substances are compared with Rf values of unknown substances