Final answer:
Thin-layer chromatography separates compounds based on their affinity for the stationary phase relative to the mobile phase, accounting for the differences in polarity, which determines their interaction with the stationary phase and their solubility in the mobile phase.
Step-by-step explanation:
The characteristic property that thin-layer chromatography (TLC) utilizes is the affinity of the substances for the stationary phase relative to the mobile phase. In thin-layer chromatography, a mixture is applied to a plate coated with a thin layer of adsorbent material, which serves as the stationary phase. A solvent (the mobile phase) moves up the plate by capillary action.
Compounds in the mixture interact with the stationary phase and the mobile phase differently due to their distinct polarity and other chemical properties. More hydrophobic substances will move up the plate more slowly, as they interact more strongly with the stationary phase. Conversely, more hydrophilic substances will move faster as they are carried by the solvent in the mobile phase. Thus, separation occurs based on the differential interactions and retention of the compounds on the stationary phase versus how they are solubilized in the mobile phase.