Chromatography Lab

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Problem
How can you tell pigment separation by using Chromatography?

Objective
To prepare a chromatogram, separate pigments in a leaf and interpret the chromatogram.

Hypothesis
If I am to put a chromatography paper into a solvent, then it would separate the pigments depending on their Rf value. I think the pigments will separate in this order: Chlorophyll A, Chlorophyll B, Carotene, and Xanthophyll.

Introduction
Chlorophyll is the molecule that absorbs sunlight and uses its energy to synthesize carbohydrates from CO2 and water. This process is known as photosynthesis and is the basis for sustaining the life processes of all plants. Since animals and humans obtain their food supply by eating plants, photosynthesis can be said to be the source of our life also. As the chlorophyll in leaves decays in the autumn, the green color fades and is replaced by the oranges and reds of carotenoids. Xanthophyll is the yellow pigment in plants that, like chlorophyll, is responsible for the production of carbohydrates by photosynthesis.

Chromatography is any of various techniques for the separation of complex mixtures that rely on the differential affinities of substances for a gas or liquid mobile medium and for a stationary adsorbing medium through which they pass, such as paper, gelatin, or magnesia. (Dictionary.com) The Rf values for each pigment are calculated to establish the relative rate of migration for each pigment. This value represents the ratio of the distance a pigment traveled on the chromatogram relative to the distance the solvent front moved. Scientists use the Rf value of a sample to identify the molecule. Any molecule in a given solvent matrix system has a uniquely consistent Rf value.

Materials
1 large test tubes
1 piece of roam rubber
1 small test tube with chlorophyll
1 strips of chromatography paper
1 plastic test tube rack
1 cork stoppers with clips
1 spinach leaf...
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