The following are the basic principles behind chromatographic separation, except:

The following are the basic principles behind chromatographic separation, except:

• A. Partition
• B. Absorption
• C. Adsorption
• D. Ion-exchange

Answer: (B)

Chromatographic separation works because an analyte distributes between two phases, giving different affinities that lead to separation. In partition chromatography, the analyte moves between the mobile phase and a liquid stationary phase, with separation arising from differences in how strongly it prefers each phase. In adsorption chromatography, the stationary phase is a solid surface, and molecules adsorb to active sites on that surface, producing separation based on how strongly each molecule adheres. Ion-exchange chromatography relies on charged groups on the stationary phase that exchange ions with the analyte, creating selectivity through ionic interactions.

Absorption would mean the analyte is taken up into the bulk of the stationary phase rather than interacting at the interface or distributing between phases. This bulk uptake isn’t the mechanism described for standard chromatographic separation, so it isn’t considered a basic principle alongside partition, adsorption, and ion-exchange.