Methods of Separation - Chromatography Method

Chromatography is a method used to separate different substances present in a small amount within the same solution. It helps identify and isolate the individual components of a mixture. This technique is widely used in pharmaceuticals, factories, and scientific research to detect new ingredients or study the composition of mixtures. For example, chromatography can be used to separate different colours from ink or identify chemicals in medicines.

1. Aim: To separate different colours from the ink with the help of chromatography.

2. Requirements: filter paper, ink, jar, water, pencils, and scales.

3. Principle: An ink dye consists of several colours. These different dyes have different solubility. Dye with higher solubility in water dissolves quickly and moves fast with the water, and low solubility will move slowly, separating from each other.

Chromatography

4. Procedure

• Take a thin strip of filter paper
• Draw a line on it using a pencil approximately 3 cm above the lower edge. Put a small drop of ink at the centre of the line. Let it dry.
• Lower the filter paper into a jar containing water so that the drop of ink on the paper is just above the water level, and leave it undisturbed. Cover the beaker with a lid to avoid evaporation.
• After some time, observe the ink as it moves up with the water.

5. Observation

1. As water rises on the filter paper, the more soluble colours travel to the top, while the less soluble colours move upward at a slower rate.
2. We get different colors on filter paper by chromatography
3. In the process of chromatography, the coloured spot rises on the paper strip as it is soluble in water, and thus, due to its solubility, the spot rises up.

6. Inference/Result: The components of a mixture have varying solubility and can be separated using chromatography.