chromatography and spectroscopy chp 29 NOT DONE GAS CHROMATOGRPAHY YET Flashcards
1
Q
define stationary phase
A
- does not move (TLC plate)
2
Q
define mobile phase
A
- does move (normally liquid or gas)
3
Q
what’s the equation for the Rf value
A
4
Q
in gas chromatography what is the stationary phase
A
- high boiling liquid absorbed onto inert solid support
5
Q
in gas chromatography what is the mobile phase
A
- inert carrier gas such as helium/neon
6
Q
what information can be determined from a gas chromatogram
A
- retention times can be used to identify components by comparing them with known retention times of components
- peak integrations can be used to determined concentrations of components in sample
peak intergrations = area under each peak
7
Q
what type of solvents are used for NMR spectroscopy
A
deuterated solvents
^H1 replaced with H2 so doesn’t produce signal
8
Q
what can we learn from a carbon-13 NMR spectrum
A
- number of unique carbon environments - from number of peaks
- types of carbon environments - from the chemical shift
9
Q
what happens if 2 carbons are positioned symmetrically in a molecule
A
- they will have the same enviroment so will contribute to one peak
10
Q
what information does a proton NMR spectrum tell us
A
- number of unique proton environments - from number of peaks
- the types of proton environments - from the chemical shift value
- relative numbers of each type of proton - from integration traces
- number of non-equivalent protons adjacent to a given proton - from the spin-spin splitting pattern
