C1 Air quality • IC1.1
Chromatography
Learning Objectives:
•
•
To know how chromatography works.
To be able to calculate Rf values for paper
chromatography.
Key words: chromatography, mobile phase, stationary phase,
Read p138-141 to
find out more about
chromatography
C1 Air quality • IC1.1
Chromatography
as an application of dynamic equilibrium
Paper chromatogrpahy:
Mobile phase = solvent (often water) that moves up the
stationary phase carrying with it the sample.
Stationary phase = solid material that the mobile phase moves
over and which can hold onto pigments
(compounds) in the sample.
Samples can be identified by seeing how far they move up the
stationary phase compared to reference samples, which are
known.
OR
They can be identified using their RETARDATION FACTOR
Rf = distance moved by the chemical
distance moved by the solvent
C1 Air quality •
Summary
IC1.1
GC
TLC
Paper
chromatography
C1 Air quality
TLC
• IC1.1
• The stationary phase is an absorbent solid supported on a
stiff plastic sheet or glass plate.
• The mobile phase is a solvent in which the sample is
soluble. It may be 1 liquid or a mixture.
• The right choice of solvent is vital when separating complex
mixtures, such as in drug analysis.
C1 Air quality • IC1.1
Advantages
and disadvantages
Type of analysis
GC
TLC
Paper
chromatography
Advantages
Disadvantages