This document discusses the extraction and separation of chlorophyll, carotenoids, and xanthophylls from plant leaves using thin-layer chromatography. It provides background on the technique, including that leaf extracts are placed as spots on a plate coated with silica. Mobile solvents like acetone and alcohol are used to separate the pigments based on their retention values. The document also gives the historical context of thin-layer chromatography and some of the key plant pigments that can be separated this way such as chlorophyll a, chlorophyll b, lutein, and beta-carotene.