Chromatography separates mixtures based on the different rates of movement of solutes relative to the mobile phase. The correct answer is option A.

Question Breakdown

This MCQ tests the core principle of chromatography, a staple in biochemistry and GATE Life Sciences exams.

Option Analysis

• A. Different rate of movement of the solute in a column: Correct. Solutes move at varying speeds due to differential partitioning or adsorption between stationary and mobile phases.

• B. Separation of one solute from other constituents by being captured on the adsorbent: Partially true for adsorption chromatography, but not the universal principle across all types (e.g., gel filtration).

• C. Different rate of movement of the solvent in the column: Incorrect. The solvent (mobile phase) moves uniformly; separation depends on solute behavior.

• D. None of the above: Incorrect, as A defines the fundamental mechanism.

Introduction
Chromatography is based on the different rate of movement of the solute in a column, enabling separation of mixtures via stationary and mobile phases. This principle powers techniques like HPLC and gel filtration, vital for protein purification in life sciences and competitive exams like GATE.

Core Principle

Chromatography relies on solutes partitioning differently between a stationary phase (solid/liquid) and mobile phase (liquid/gas). Solutes with stronger stationary phase affinity move slower, creating separation based on differential migration rates.

Types and Mechanisms

• Adsorption: Solutes bind to solid stationary phase surfaces.

• Partition: Solutes distribute between liquid phases.

• Ion-exchange/Size-exclusion: Charge or size dictates movement rates.

Applications

Used in pharma for drug purity, biotech for protein analysis, and forensics for toxin detection.