Slide 1: 0 Chromatography is a method of physically separating mixtures of gases, liquids, or dissolved substances.
Chromatography can be used to identify drugs, poisons and many other substances.
Separation is determined by the molecular size and/or charge Slide 2: 1 All forms of chromatography involve 2 phases
The Two Phases
1. stationary (absorbent) phase
the material on which the separation takes place
2. mobile phase - the solvent transports the sample
Types of Chromatography - 5 of them Gas Chromatography : 2 Gas Chromatography Gas Chromatography
a gas separates the components
they are then ionized and an electrical signal is recorded
mobile phase - carrier gas
- thin film of liquid HPLC : 3 HPLC High Performance Liquid Chromatography (HPLC)
- done at room temp. - advantageous for chemicals that are heat sensitive or volatile - example LSD
- a liquid (mobile phase) is pumped through a column containing fine particles (stationary phase) TLC : 4 TLC Thin - Layer Chromatography (TLC)
-A plate is coated with a granular gel - usually silica gel or aluminum oxide (stationary phase)
- the substance to be separated is carried up the plate by capillary action - the substance with most affinity for the plate will rise the farthest.
4. Paper chromatography
Same as TLC but paper
is used as stationary phase Electrophoresis : 5 Electrophoresis Electrophoresis
- Similar to TLC but the substance is separated through a gel by electric current
- Due to different size and charge substances will move across the plase at different speeds. Paper Chromatography of Ink : 6 Paper Chromatography of Ink Two samples of black ink from two different manufacturers have been characterized using paper chromatography. Retention Factor (Rf) : Retention Factor (Rf) A number that represents how far a compound travels in a particular solvent
It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled. Solve for Rf : 8 Solve for Rf