Chapter 29 - Chromatography and Spectroscopy Flashcards
What are the two phases for all forms of chromatography?
Stationary phase
Mobile phase
What is the stationary phase?
Does not move
A solid or a liquid supported on a solid
What is the mobile phase?
Does move
Normally a liquid or a gas
What is a TLC plate made of?
Plastic/glass sheet
Coated with thin layer of a solid adsorbent substance such as silica
Outline adsorption in reference to TLC
Process by which the solid silica holds the different substances in the mixture to its surface
How is the retention factor calculated?
Distance moved by the component/distance moved by the solvent front
What is gas chromatography useful for?
Separating and identifying volatile organic compounds present in a mixture
What are the different phases for gas chromatography?
Stationary - high boiling liquid adsorbed onto an inert solid support
Mobile - inert carrier gas such as helium
How does time taken to move through the column change as solubility in stationary phase increases?
Moves slower
Time taken increases
What is retention time?
Time taken for a component to travel through the column
How is retention time used for identification?
Compare to retention times in database
What can peak integrations for gas chromatograph be used to determine?
Concentrations of components in the sample
What is resonance for NMR?
When the nucleus absorbs energy and rapidly flips between the two spin states
What is the standard reference chemical for NMR?
Tetramethylsilane (TMS)
(CH3)4Si
What is the purpose of D2O as a solvent in proton NMR spectroscopy?
O-H peaks no longer appear
