Chromatography

Chromatography is the collective term for a set of laboratory techniques used to separate mixtures.

It involves passing a mixture dissolved in a "mobile phase" through a “stationary phase” which separates the mixture into components based on their different affinities for the mobile and stationary phases.

NOTE: Components separate out due to differences in affinity for each phase NOT due to differences in the molecular size of each component – polarity is important, molecular mass is not.

In paper chromatography, paper serves as the stationary phase and a solvent serves as the mobile phase.

Paper Chromatography

You will test 3 different ink mixtures (pens) and 2 different plant pigment mixtures.

You will test 5 different solvents on each ink or plant pigment mixture.

You will calculate Rf values for every pigment that separates out from each mixture.

These solvents, especially Petroleum ether, can be hazardous to your health. As such:

Do not handle Petroleum ether if you have a medical condition or might be pregnant.

You must wear goggles and gloves when handling solvents.

All solvents must be poured under a fume hood and must remain covered while at your station.

All solvents must be disposed of in the appropriate waste containers.