Paper Chromatography Lab Technique Materials Whats Needed Chromatography

Paper Chromatography Lab Technique

Materials • What’s Needed: – Chromatography Paper – Solvent (Petroleum Ether / Acetone) – Substance (concentrated solution) – Closed container

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Background Info. • 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 H 2 O). – 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 pigment molecules – Chlorophyll a, chlorophyll b, xanthophyll & carotene

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More Results / Data • Looking for pigment distance traveled. • Can calculate Rf (Retention factor). • Rf = Distance traveled by pigment / distance traveled by solvent.