One way they can do this is to use a process called chromatography. In the activity below, you can try chromatography to separate colors in a mixture of food coloring! Place a coffee filter on a tray ...

Thin-layer chromatography (TLC) was widely used in the 1960s and 1970s for pesticide residue analysis, but only to a limited extent since gas–liquid chromatography (GLC) and high performance liquid ...