Gas Liquid chromatography Flashcards
What is the stationary phase?
Where the molecules can’t move, must be a solid or a liquid on a solid support
In this case, oil which coats a porous support inside a long tube
What is the mobile phase?
Where the molecules can move, always a liquid or a gas.
In this case it’s an inert (unreactive) carrier gas such as nitrogen or helium.
How does solubility affect retention time in GLC?
If a substance is more soluble in the mobile phase, then the retention time will be smaller, vice versa.
How does the temperature of the GLC machine effect retention time?
The hotter the GLC machine the more time the substance remains in the evaporated state, therefore moving through the tube quicker, reducing retention time.
How does boiling point affect retention time?
If a substance has a high boiling point, it’s more likely to travel through as a liquid rather than gas, therefore increasing retention time.
Why is combining GLC with mass spec a useful tool for analysis?
It makes it easy to identify the components of a mixture, as GLC is very good at separating liquids, and mass spec allows us to identify compounds.
