Separates substances w/in a mixture based on their physical properties Used to: - analyze dyes in...
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Transcript of Separates substances w/in a mixture based on their physical properties Used to: - analyze dyes in...
• 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
• Rf value = retention factor - qualitative comparison b/t length of
time substance is in mobile & stationary phases
Rf = 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