Separates substances w/in a mixture based on their physical properties Used to: - analyze dyes in fibers - test for explosives or accelerants - check body fluids for drugs

Paper Chromatography – small amount of substance placed near bottom of paper, bottom placed in solvent - solvent moves up paper = mobile phase - paper itself = stationary phase - As solvent moves, different components of mixture adhere to paper at different places

Chromatogram – shows substances dissolved in original mixture & how far solvent traveled

R f value = retention factor - qualitative comparison b/t length of time substance is in mobile & stationary phases R f = distance substance traveled distance solvent traveled - depends on type of solvent - solvent front = line where solvent stopped moving

Thin Layer Chromatography (TLC) - similar to paper, but faster & clearer - use thin layer of gel-like material on a glass or plastic plate - good to separate dyes & inks

Gas Chromatography (GC) - at high temps - useful to separate mixtures w/ large molecules (ex. Proteins in blood)

High Performance Liquid Chromatography (HPLC) - at room temp - uses high pressure to force mixtures through a column of liquid