Analytical techniques Flashcards
1
Q
Infrared radiation
A
- causes covalent bonds to vibrate
- different bonds have different absorptions
- frequency where they vibrate
2
Q
Greenhouse gases
A
- absorb infrared radiation
- high atmospheric concentration
- long residence time
- randomly disperses energy
- have C=O, C-H, O-H
3
Q
CH3+ fragment
A
15
4
Q
CH3CH2+ fragment
A
29
5
Q
CH2OH+ fragment
A
31
6
Q
Molecular ion
A
- peak with largest m/z value
- Mr of molecule
7
Q
M+1 peak
A
- above molecular ion
- presence of carbon13 isotope
8
Q
Stationary phase
A
solid
liquid held by solid support
9
Q
Mobile phase
A
moves through stationary phase
liquid or gas
10
Q
Factors for chromatography separation
A
- extent of solubility in mobile phase
- adsorption to solid stationary phase
11
Q
Thin layer chromatopgraphy
A
- Aluminium oxide or silicon oxide on glass plate is stationary phase
- sample spotted onto plate
- in shut container with solvent
- use iodine crystal, UV or ninhydrin to make colourless compounds visible
12
Q
Rf
A
distance moved by solute/ distance moved by solvent
13
Q
Gas chromatography
A
- sample vaporised and injected
- carrier gas- mobile phase (nitrogen)
- flows under pressure through column
- stationary phase- liquid or solid on solid support
- components separate as pass through column
- separately detected by signal when emerge
- retention time recorded
14
Q
Retention time
A
time between injection of the sample and the emergence of a component from the column
15
Q
Retention area
A
area = base x 1/2 x height
amount of component
