Chapter 29
29.1 CHROMATOGRAPHY AND FUNCTIONAL GROUP ANALYSIS
What is the purpose of chromatography? To separate individual components from a
mixture of substances
What are the two phases called? Stationary and mobile phase
What is the stationary phase? It does not move and is normally a solid or a
liquid supported on a solid- the adsorbent
What is the mobile phase? It does move, and is normally a liquid or gas
(solvent)
What is the surface in TLC? A plate which is usually a plastic sheet or glass,
coated with a thin layer of a solid adsorbent
substance, usually silica
The differing components in the mixture have Affinities for the absorbent and bind with
different what? differing strengths to its surface
What is adsorption? The process by which the solid silica holds the
different substances in the mixture to its surface.
How do you carry out TLC?
How to get sample?
Where to put it?
How to prepare tank?
During it?
When to remove it?
After it?
How are chromatograms analysed? By calculating retention factor for each
component. Each component can be identified
by comparing its Rf value with known values
recorded using the same system and absorbent.
, Chapter 29
Rf equation? Distance moves by the component
Distance moved by the solvent front
What is gas chromatography used for? Separating and identifying volatile organic
compounds present in a mixture
What is the stationary phase? A high boiling liquid adsorbed onto an inert
solid support.
What is the mobile phase? An inert carrier gas such as helium or neon
Explain how gas chromatography works
Retention time The time taken for each component to travel
through the column
Retention times can be used to what? Identify the components present in the sample
by comparing these to retention times for known
components
Peak integrations Areas under each peak
Peak integrations can be used to what? Determine the concentrations of components in
the sample
How do you determine the concentration of a
component in a sample in a practical way?
29.1 CHROMATOGRAPHY AND FUNCTIONAL GROUP ANALYSIS
What is the purpose of chromatography? To separate individual components from a
mixture of substances
What are the two phases called? Stationary and mobile phase
What is the stationary phase? It does not move and is normally a solid or a
liquid supported on a solid- the adsorbent
What is the mobile phase? It does move, and is normally a liquid or gas
(solvent)
What is the surface in TLC? A plate which is usually a plastic sheet or glass,
coated with a thin layer of a solid adsorbent
substance, usually silica
The differing components in the mixture have Affinities for the absorbent and bind with
different what? differing strengths to its surface
What is adsorption? The process by which the solid silica holds the
different substances in the mixture to its surface.
How do you carry out TLC?
How to get sample?
Where to put it?
How to prepare tank?
During it?
When to remove it?
After it?
How are chromatograms analysed? By calculating retention factor for each
component. Each component can be identified
by comparing its Rf value with known values
recorded using the same system and absorbent.
, Chapter 29
Rf equation? Distance moves by the component
Distance moved by the solvent front
What is gas chromatography used for? Separating and identifying volatile organic
compounds present in a mixture
What is the stationary phase? A high boiling liquid adsorbed onto an inert
solid support.
What is the mobile phase? An inert carrier gas such as helium or neon
Explain how gas chromatography works
Retention time The time taken for each component to travel
through the column
Retention times can be used to what? Identify the components present in the sample
by comparing these to retention times for known
components
Peak integrations Areas under each peak
Peak integrations can be used to what? Determine the concentrations of components in
the sample
How do you determine the concentration of a
component in a sample in a practical way?
