Question

Explain the principle of paper chromatography.

Answer 1

Hint: This technique is classified under the chromatography for the separation of a mixture. As the name suggests, it is based on the use of paper, and it is relatable to the adsorption process. So, we can explain the principle of paper chromatography.

Complete answer:
- First let us define paper chromatography. As mentioned before, it involves the use of pape, or strips, that act as an absorbent, and stationary phase. So, the solution is allowed to pass through the stationary phase, i.e. paper. Thus termed as paper chromatography.
- This process is not costly, and considered to be a powerful analytical tool. In this technique, chemical substances with different migration rates are passed through the paper for separation.
- This technique was discovered by Synge, and Martin.
- Now, the principle involved in paper chromatography is related to the adsorption process, or the partition technique.
- Let us now understand the partition technique. In this technique, substances are being distributed between the two liquid phases.
- One phase is stationary i.e. pores of filter paper holding the water, and other one is a mobile phase which is passing through the paper. Thus, the separation of mixture will take place by the movement of the mobile phase.
- Now, the absorption takes place between one solid phase, and the liquid phase. The stationary phase is the solid surface of the paper, and the mobile phase is the liquid that will pass through it.
- Hence, this technique involves the use of paper, which acts as a stationary phase for the separation of mixture.

Note: Don't get confused between partition technique, and adsorption technique. Partition techniques are liquid-liquid separation, whereas adsorption technique is solid-liquid separation.