A. Non-polar

B. Polar

C. Either non-polar or polar

D. None of these

Reverse phase chromatography uses a non-polar stationary phase paired with a polar mobile phase. The correct answer is option A.

Question Breakdown

This MCQ evaluates knowledge of reverse phase (RP) chromatography fundamentals, a key topic in GATE Life Sciences for protein and analyte separation.

Option Analysis

• A. Non-polar: Correct. RP chromatography employs hydrophobic stationary phases like C18 or C8 silica, retaining non-polar analytes longer.

• B. Polar: Incorrect. Polar stationary phases define normal phase chromatography, not reverse phase.

• C. Either non-polar or polar: Incorrect. RP specifically requires non-polar stationary phase by definition.

• D. None of these: Incorrect, as A accurately describes the principle.

Introduction
In reverse phase chromatography, the nature of the stationary phase is non-polar, typically C18-bonded silica, which retains hydrophobic molecules while a polar mobile phase (water/acetonitrile) elutes them. This “reverse” of normal phase is essential for biomolecule analysis in biochemistry and GATE Life Sciences exams.

Mechanism Details

Non-polar stationary phase interacts via hydrophobic forces with non-polar analytes. More hydrophobic compounds elute later as mobile phase polarity decreases (gradient elution).

Common phases: C18 (strong retention), C8 (moderate), phenyl (aromatic selectivity).

Comparison Table

Applications

• Peptide/protein separation

• Drug metabolite analysis

• Pharma quality control