Separation of Photosynthetic Pigments by Paper Chromatography

Photosynthetic pigments are the organic compounds present in plants that play a vital role in the process of photosynthesis. These pigments absorb light energy and convert it into chemical energy, which is used by plants for their growth and development.

Paper chromatography is a technique used for separating the components of a mixture based on their ability to move through a stationary phase. In the case of photosynthetic pigments, paper chromatography can be used to separate the different pigments present in the plant extract.

Steps involved in separation of photosynthetic pigments by paper chromatography:

1. Preparation of the plant extract: The first step in separating the photosynthetic pigments by paper chromatography is to prepare a plant extract. This can be done by crushing the leaves of the plant in a mortar and pestle and then adding a solvent such as acetone or ethanol to extract the pigments.

2. Spotting the extract on the paper: A small amount of the plant extract is then spotted onto a piece of filter paper, usually near the bottom of the paper.

3. Development of the chromatogram: The paper is then placed in a developing solvent, such as petroleum ether or ethanol, and allowed to develop. As the solvent moves up the paper, it carries the pigments along with it. Each pigment moves at a different rate based on its solubility in the solvent and its attraction to the paper.

4. Visualization of the pigments: Once the chromatogram has been developed, the different pigments can be visualized by placing the paper under UV light or by spraying it with a chemical reagent such as iodine or ninhydrin.

5. Calculation of the Rf value: The Rf value is the ratio of the distance moved by the pigment to the distance moved by the solvent. This value can be used to identify the different pigments present in the plant extract.

In conclusion, paper chromatography is a useful technique for separating the different photosynthetic pigments present in plants. It is a simple and inexpensive method that can be used to identify the different pigments and to study their properties.