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