In chromatography, which technique uses filter paper as the adsorbent?

• A. Gas chromatography
• B. Column chromatography
• C. Paper chromatography
• D. Thin layer chromatography

Answer: (C)

Paper chromatography relies on filter paper as the stationary phase. The cellulose fibers in the paper hold a thin layer of adsorbed water, which acts as the phase with which the analytes partition. As the solvent moves up the paper by capillary action, each compound travels at a different rate depending on how strongly it interacts with the water in the paper versus the solvent, producing separated spots at different heights. Other chromatography methods use different stationary phases, such as columns packed with solid adsorbents, or plates coated with silica or alumina, or a gas moving through a column, so they don’t rely on filter paper. This combination of a paper-based stationary phase and a moving solvent is what defines paper chromatography.