The Write Stuff: Using Paper Chromatography to Separate an Ink Mixture

In this Activity, students perform a variation on the standard paper chromatography separation of black ink. They compare the separation of black ink using four different solvents: water, rubbing alcohol, vinegar, and household ammonia, and then mixtures of the four. It introduces students to methods of selecting the best solvent for a separation and the effects of adding acid and base. This Activity can lead to a discussion of mixtures and ways to separate their components. Capillary action, solute-solvent interaction, and differences in polarity and solubility are related topics.