Chromatography Flashcards
Which two phases does chromatography rely on?
Stationary phase and mobile phase
What is a phase in chromatography?
A substance in the solid, liquid or gas state.
What are the phases in paper chromatography?
The stationary phase is the absorbent paper and the mobile phase is the solvent in the liquid state.
Thin-layer chromatography works in the same way as paper chromatography, but what is used instead of the absorbent paper?
A thin layer of silica or alumina powder spread over a plate of glass or plastic.
What are the phases in gas chromatography?
Stationary phase is silica or alumina powder packed into a metal column and the mobile phase is an unreactive carrier gas such as nitrogen
What is the formula for Rf values?
Rf = distance travelled by substance / distance travelled by solvent
Why is thin-layer chromatography better than paper chromatography?
Quicker, more sensitive and has a larger range of solvents and stationary phases to choose from.
