Chromatography

• Paper chromatography

  1. Draw start line near bottom of paper

  2. Spot mixture on line

  3. Fill beaker with small amount of solvent

  4. Hang paper on rod and place in beaker

  5. Solvent travels up paper, separating components

  6. Before solvent reaches end, take out paper and mark finish line, then dry paper
• Procedure works

  When different compounds have different affinities for the solvent/paper. Stronger attraction for the paper - travels slowly with the solvent
• Paper

  Stationary phase - doesn't move
• Solvent

  Mobile phase
• how is Rf calculated

  distance moved by the spot / distance moved by solvent
• in paper chromatography experiment, a compound A was found to have an Rf value of 0.85 - what does it tell you about the compound?

  has a higher affinity for the solvent than for the paper