Chromatography 2 Flashcards
1
Q
What is column chromatography?
A
- uses poweder, such as silica, aluminium oxide, as the stationary phase
- packed in to narrow tube, the column, and a solvent (the eluent) is added to the top
2
Q
How does column chromatography used?
A
- as the eluent runs down the column, the components of the mixture move at different rates and can be collected seperately in flasks at the bottom
3
Q
Why are more than one eluents often used?
A
- better seperation
4
Q
What is the advtangge of column chromatography?
A
- large amounts can be separated and collected
5
Q
What is gas chromatography used for?
A
- mixture of voltaile liquids
6
Q
How does gas chromatography used?
A
- stationary phase is a solid or a solid coated by a viscous liquid, such as oil, packed in long tube
- the tube is coiled to save space and built into an oven
- mobile phase is an unreactive carrier gas such as nitrogen
7
Q
How are the gases separated?
A
- each component takes a different amount of time from being injected to being recorded
- this is retention time
- each seperate susbtance will have a uniquie retention time
- identify components
8
Q
What does the area uinder the curve of a recorder response and time graph in the GC chromatogram
A
relative amounts
9
Q
How is GC used?
A
- find alcohols level in blood or urine
- propoprtions of ester in oils used in paints
10
Q
What is GC-MS
A
- gas chromatography - mass sepctrometry
- combines benefits of GC and MS to make a super analysis tool
11
Q
How does GC-MS used~?
A
- sample separated using gas chromatography, but instead of fed into a detector, the seperated components are fed into a mass spectrometer
- the spectrometer produces a mass spectrum for each component, which can be used to identify each one and show what the original sample consisted of
12
Q
What is the advantage of GC-MS?
A
- components seperated by the chromatography can be postively identified, which can be impossible from a chromatogram alone
- natched up to mass spectrum against a database
