What Is Paper Chromatography?
Paper chromatography is an analytical technique used to separate and identify dissolved chemical substances within a mixture by exploiting their different rates of migration across a sheet or strip of paper
. It is a simple, inexpensive, and effective method that requires only small amounts of material. How It Works
- A small spot of the sample mixture is applied near one end of a piece of specialized filter paper.
- The edge of the paper is then placed in a solvent (the mobile phase), while the paper itself acts as the stationary phase.
- The solvent moves through the paper by capillary action, carrying the components of the mixture with it.
- Different substances in the mixture travel at different speeds, depending on their solubility in the solvent and their affinity for the paper.
- This causes the components to separate into distinct spots or bands along the paper
Principle The separation is based on the differential partitioning or adsorption of the compounds between:
- The stationary phase (water molecules held in the pores of the paper or the cellulose fibers themselves)
- The mobile phase (the solvent moving through the paper)
Compounds with a higher affinity for the solvent move further, while those with a stronger attraction to the paper move less
. Applications Paper chromatography is widely used to separate and identify:
- Amino acids
- Peptides
- Carbohydrates
- Plant pigments
- Inorganic ions
- Dyes and food additives
It is commonly used in chemistry, biology, forensic science, and environmental testing
. Key Points
- Invented by Synge and Martin in 1943
- Mainly used for qualitative analysis.
- Types include ascending, descending, radial, and two-dimensional paper chromatography
Paper chromatography remains a fundamental technique for analyzing complex mixtures in both research and educational settings
