Gas Chromatography BasicsGas Liquid Chromatography (GLC)Gas Solid Chromatography (GSC)Mobile phase does not interact with
analyteSeparation occurs by interaction of
analyte differentially w/liquid stationary phase and temperature
GC preferred method, only applicable to volatile substances
derivitiazation
Carrier Gas Supply
• Must be at a constant flow rate so that retention times & retention volumes may be equated
• Choice of detector will often
• Dictate the gases that are used, need to be inert Ex. FID used H2, air, and He
Injection Port
• Heated so sample virtually instantly turns into a vapor as sample plug goes onto column
• Septum• Split/ Splitless
Want to reproducibly get in & get out Sample focus
GC ColumnsCapillary:
- have i.d. <1mm- have wide unrestricted flow through center & inner surface is coated with liquid stationary phase
• Variety of functional groups have been blended into polysiloxane chain to provide different polarity & selectivity
Chromatography Catalog Exercise• Determine the best type of column to achieve
separation for drugs of abuse.• Draw the chemical structures of the stationary
phase as best you can.• Indicate what chromatographic conditions you
would do your separation under.• Why do you think the catalog recommended
the conditions they did? • Compare with someone else who used a
different catalog, explain any differences.