1. Gas Chromatography

2. Basic Description
Chromatography is a method for separating the components of a mixture by differential adsorption between a stationary phase and a mobile (moving) phase

3. Uses for Chromatography
Chromatography can be used to:
Qualitatively analyze the number of components in a mixture
Qualitatively identify the components of a mixture using known compounds
Quantitatively determine the amount of a component in a mixture using standard samples
Purify individual components by separating them from the other compounds in a mixture

4. The Basics Mixture is placed on stationary phase
Mobile phase passes over the stationary phase
Mobile phase carries the individual components through the stationary phase, depending on their attraction to both of the phases

5. Rf ratio of spot distance to solvent front distance
Chromatographed
Spot
Rf ratio of spot distance to solvent front distance
Put the spotted paper in a developing tank
Origin line
Solvent

6. Other Kinds of Chromatography
Liquid chromatography (includes column chromatography, thin-layer, and HPLC)
Stationary phase: silica, alumina, modified surfaces, etc.
Mobile phase (moving phase): aqueous or organic solvents
Important properties: polarity, charge, etc.
Gas chromatography
Stationary phase: a film of a polymer or a wax. The film must have a low volatility
Mobile phase: gas (Helium is a common carrier gas)
Important properties: boiling point, volatility, etc.

7. The Basic Gas Chromatograph

8. Vernier GC

9. A Chromatogram 5 1. Acetone 2. Methanol 3 3. Butanol 1 4. Acetic Acid
5. Butyric Acid 2 4

10. This Week’s Lab Forensic in nature
Start with FTIR to decide what compound class your “unknown” belongs to.
Run authentic compounds in that class
Separation is based predominantly on boiling point rather than differential interaction with stationary phase
Run the “unknown” to determine individual identities

11. Logger Pro Update
You need the latest Logger Pro Update to operate the gas chromatograph from your laptop computer. Go to Select Downloads Select Logger Pro Update Install Correct version for your OS

12. Writing the Report
Clearly state your experimental methods and how those procedures yielded the solution to the problems addressed in the investigation.
State what data you collected and how you analyzed the data.
Include properly designed and illustrative data tables.
Show structures of all possible compounds in your compound class.
Discuss other places that GC might be used beyond this investigation and those described in the Introduction.