• What’s Needed:
–Solvent (Petroleum Ether /
• A concentrated solution is applied to
an area on the chromo paper.
• Chromo Paper is dipped in a solvent.
• Solvent moves up the paper via
capillary action (ability of a substance
to draw another substance to it; i.e.
adhesion/cohesion of H2O).
–This is due to the solvent molecules’
attraction to the chromo paper.
• As the solvent meets the concentrated
solution it dissolves it.
• The solvent and now dissolved
solution move up the paper.
• Different substances in the solution
travel up the paper at different rates.
–This is due to differences in solubility
in the solvent.
–Also due to differences in attraction
to the paper fibers.
Time / Results
• Time: Takes minutes to hours
depending on the substance.
• Results: We are looking for 4
– Chlorophyll a, chlorophyll b,
xanthophyll, & carotene.
More Results / Data
• Looking for pigment distance
• Can calculate Rf (Retention factor).
• Rf = Distance traveled by pigment /
distance traveled by solvent.