Paper chromatography of leaf pigments

Where to buy & price

Just examples of where to look and roughly what to expect to pay, get everything from wherever works for you, at whatever price you find.

Spinach/sukuma wiki ~KSh 20–30/bunch. Rubbing alcohol (same source as the DNA extraction experiment). Coffee filters ~KSh 100–200/pack.

Cold storage / timing

None.

Reagents & materials required

Procedure, step by step

1. 1

   Tear a handful of fresh spinach or sukuma wiki leaves into small pieces and place them in a small jar or mortar.

2. 2

   Crush and grind the leaves thoroughly, then add just enough rubbing alcohol to cover them, and keep grinding/stirring for a few minutes to help the pigments dissolve into the alcohol.

3. 3

   Cut a strip of coffee filter paper about 2cm wide, long enough to reach into a jar without the top touching the liquid.

4. 4

   Draw a light pencil line about 2cm from one end of the strip. Dip a small brush or capillary tube into the leaf-alcohol extract and apply a small, concentrated spot directly onto that line, let it dry, then repeat 3–5 times in the same spot to build up a concentrated pigment dot.

5. 5

   Pour fresh rubbing alcohol into a jar, just enough to cover the very bottom (about 0.5cm deep), and hang the strip so its bottom edge touches the alcohol while the pigment spot itself stays above the liquid.

6. 6

   Cover the jar loosely and let the alcohol wick up the paper for 20–40 minutes, watching it carry the different pigments upward at different speeds.

7. 7

   Remove the strip once the solvent has traveled most of the way up, immediately mark how far the solvent itself reached, then let the strip dry.

8. 8

   Observe and record the distinct color bands on the dried strip, typically green chlorophyll bands and yellow or orange carotenoid bands.