Chromatography

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

Equipment:
Ink pens, test tube, a strip of paper, chromatography solution.

Method:
1. Cut a piece of filter paper long enough to reach the bottom of your test tube.
2. Rule a line in pencil, 2m from the bottom of the paper.
3. Fill the test tube with 1cm of chromatography solution. (water)
4. Place a dot of ink above the ruled line.
5. Fold over test tube and place in solution.
6. Wait and observe.
7. Repeat with 2 other colours.

Results:

The water rose up the paper, eventually reaching the ink blobs we created using felts, resulting in a weird moving blob effect when it came into contact with the ink. Colours made out of other colours (Purple: red and blue / Orange: Red and yellow, e.t.c.), because the two colours would separate and run along the paper. Also, colours often darkened when dissolved in the mobile phase.

Discussion:
Chromatography, meaning 'colour writing' in Greek, is the idea of separating a mixture. The mixture is dissolved in a fluid, (Water,) called the "mobile phase." The mobile phase carries the mixture along another material (Paper), called the "stationary phase." This kind of chromatography is called 'Paper Chromatography.'