Thin layer chromatography (TLC) | Chemical processes | MCAT | Khan Academy

Obtain a TLC plate coated with silica gel, which serves as the stationary phase. Use a spotting tool to apply a small dot of the sample from the reaction flask onto the plate near the bottom.

Pour a small amount of the mobile phase solvent (or solvent mixture) into the development chamber. Place a piece of filter paper inside to saturate the chamber with solvent vapor, ensuring uniform distribution throughout.

Insert the TLC plate with the sample spot into the development chamber containing the mobile phase. Close the chamber lid immediately to prevent volatile organic solvents from evaporating.

Watch as the mobile phase travels up the silica gel plate through capillary action. When the solvent front approaches the top edge, remove the plate from the chamber and mark the solvent front line with a pencil.

Expose the plate to a UV lamp to reveal the separated compounds as glowing spots. Aromatic compounds will typically fluoresce and become visible under UV illumination.

Analyze the migration distance of each spot to determine compound polarity. Spots that traveled far indicate less polar compounds with strong mobile phase affinity, while spots that remained near the origin indicate more polar compounds with strong silica gel affinity.

Compare the observed spots and migration patterns with known reference compounds to identify the components. Match the polarity characteristics and Rf values to determine which compounds are present in the original reaction mixture.