Chromatography

Aim: To separate the different pigments in inks using paper chromatography.

Equipment: Ink pens, small beaker, strip of filer paper, ice-block stick, tape, chromatography solution, test tube.

Method:

1. Cut a piece of filter paper long enough to reach the bottom of your test tube.
2. Rule a line in pencil 2cm from the bottom of the paper.
3. Fill test tube with 1cm of chromatography solution (water)
4. Place a dot of ink above the ruled line on your filted paper. You need to produce a concentrated dot of ink so repeat applications may be necessary.
5. Suspend the strip of paper from the pencil or stick. You may need to use adhesive tape to stop it from falling into the solution.
6. Wait to see what happens. It is important that you do not disturb the beaker. If the solution comes in contact with the ink dot, the ink will run down into the solution, rather than move up the filter paper.

Results: 

Here is a 5 minute time lapse I did: 

Discussion: The filtered paper observed the the solute which was the water. The water then reached the solvent which was the ink. When it reached it, it carried the colour further up the paper through the solvent (water) and that was the solution. It left a nice bled-though like ink going upwards. I did black a pink and then purple; which didn't really work since the first dot was underwater so I did another dot above it and it kinda just failed in general. The black seemed to work better than the pink ink. The process of separating two (or more) pigment colours is called Chromatography.