Paper Chromatography Principles

Study Notes

Principle

Paper chromatography is a type of planar chromatography that uses a stationary phase of paper to separate, identify, and quantify components of a mixture.
It is based on the principle of partition chromatography, where the components of the mixture are distributed between the paper and a solvent.

Apparatus

A rectangular piece of filter paper (stationary phase)
A solvent (mobile phase)
A pencil or marker
A ruler or straightedge
A solvent reservoir
A chromatography chamber (optional)

Procedure

Sample Application
- A small amount of the mixture is applied to the paper as a spot or a line, about 1-2 cm from the top edge.
- The sample should be applied in a minimal volume to prevent spreading.
Solvent Migration
- The paper is placed in the chromatography chamber, and the solvent is allowed to migrate up the paper by capillary action.
- The solvent front is marked with a pencil or marker as it migrates.
Separation and Detection
- The components of the mixture separate based on their affinities for the paper and solvent.
- The separated components can be detected using various methods, such as:
  - Visual observation (e.g., color, fluorescence)
  - Chemical testing (e.g., ninhydrin for amino acids)
  - Instrumental methods (e.g., densitometry)

Factors Affecting Separation

Solvent composition: The choice of solvent affects the separation of components.
pH: The pH of the solvent can influence the separation of ionizable compounds.
Temperature: Temperature can affect the rate of solvent migration and component separation.
Paper type: The type of paper used can influence the separation of components.

Applications

Biochemistry: Paper chromatography is used to separate and identify amino acids, sugars, and other biomolecules.
Forensic science: It is used in forensic analysis to identify and compare substances, such as ink, dyes, and drugs.
Food analysis: Paper chromatography is used to detect and quantify food additives, contaminants, and nutrients.

Principle of Paper Chromatography

Partition chromatography is the principle behind paper chromatography, where components of a mixture are distributed between the paper and a solvent.

Apparatus Used

Rectangular piece of filter paper (stationary phase)
Solvent (mobile phase)
Pencil or marker
Ruler or straightedge
Solvent reservoir
Chromatography chamber (optional)

Procedure of Paper Chromatography

A small amount of the mixture is applied to the paper as a spot or a line, about 1-2 cm from the top edge.
The sample should be applied in a minimal volume to prevent spreading.
The paper is placed in the chromatography chamber, and the solvent is allowed to migrate up the paper by capillary action.
The solvent front is marked with a pencil or marker as it migrates.

Separation and Detection

Components of the mixture separate based on their affinities for the paper and solvent.
Separated components can be detected using various methods, including:
- Visual observation (e.g., color, fluorescence)
- Chemical testing (e.g., ninhydrin for amino acids)
- Instrumental methods (e.g., densitometry)

Factors Affecting Separation

Solvent composition affects the separation of components.
pH of the solvent influences the separation of ionizable compounds.
Temperature affects the rate of solvent migration and component separation.
Type of paper used influences the separation of components.

Applications of Paper Chromatography

Biochemistry: separates and identifies amino acids, sugars, and other biomolecules.
Forensic science: identifies and compares substances, such as ink, dyes, and drugs.
Food analysis: detects and quantifies food additives, contaminants, and nutrients.

Description

This quiz covers the principles of paper chromatography, a type of planar chromatography used to separate, identify, and quantify components of a mixture. Learn about the stationary and mobile phases, and how they work together to achieve separation.