A. Ions that are not dissolved in a solvent

B. Ions that are dissolved in a solvent

C. Ions that are dissolved in a solute

D. All of the above

Correct Answer: B. Ions that are dissolved in a solvent

Liquid chromatography separates ions dissolved in a solvent (mobile phase) through interactions with a stationary phase, commonly via ion-exchange or ion-pair mechanisms.

Option Analysis

A. Ions that are not dissolved in a solvent
Incorrect. Undissolved ions (solids/precipitates) cannot enter the liquid mobile phase to interact with the stationary phase, preventing chromatographic separation.

B. Ions that are dissolved in a solvent (Correct)
Liquid chromatography requires ions in solution. Ion-exchange chromatography uses charged stationary phases to selectively retain and elute dissolved ions based on charge and affinity. Examples include anion/cation separation in HPLC.

C. Ions that are dissolved in a solute
Scientifically invalid terminology. Solutes dissolve in solvents to form solutions; ions cannot dissolve “in a solute.” This option misuses basic solution chemistry concepts.

D. All of the above
Incorrect, as options A and C are impossible. Only dissolved ions (B) participate in liquid chromatography separation processes.

Liquid chromatography separates ions dissolved in solvent through selective interactions between charged analytes and stationary phases—essential for biochemistry purification in GATE Life Sciences.

Separation Mechanism

Dissolved ions partition between liquid mobile phase and charged stationary phases (cation/anion exchange resins). Retention depends on charge, size, and eluent ionic strength, enabling baseline resolution.

Technique Applications

GATE Relevance

Critical for analytical biochemistry questions testing separation principles across molecular biology and pharmaceutical analysis contexts.