1. PHOTOSYNTHESIS: THIN LAYER CHROMATOGRAPHY.
A2 BIOLOGY.
PHOTOSYNTHESIS: THIN LAYER CHROMATOGRAPHY.

2. Typical results.

3. Typical results.
Position of solvent front.
Origin.

4. Typical results.
Position of solvent front.
Mark centre of each solvent front eg.
Origin.

5. Typical results.
Position of solvent front.
Origin.

6. Measure distance from Origin to each spot and the solvent front.
Calculate Rf value for each spot
Rf = distance moved by spot (M)
distance moved by solvent (N)
3. Identify chlorophyll A and B from following table:

7. Typical results. N M
Rf = M N

8. Measure distance from Origin to each spot and the solvent front.
Calculate Rf value for each spot
Rf = distance moved by spot
distance moved by solvent
3. Identify chlorophyll A and B from following table:
PigmentPigment
Rf value
Chlorophyll A
0.58
Chlorophyll B
0.40
Lutein
0.24
Phaeophytin
0.86
Vidaxanthin
0.10

9. Key points.
The Rf value depends on the solvent used. It will affect how fast each solute travels up the paper.
Different plants will have evolved to produce different types of pigment. Seaweeds are a good example of this.
distance moved by solvent
3. Rf = retardation factor.
Retardation is by interaction with the paper(stationary phase), stronger interactions produce greater retardation and chemical spends less time dissolved in solvent (mobile phase).
Review two-way chromatography.