Comparing types of chromatography: including gas chromatography
I can identify features of different types of chromatography and describe how the techniques are used to separate and identify components of a mixture.
Comparing types of chromatography: including gas chromatography
I can identify features of different types of chromatography and describe how the techniques are used to separate and identify components of a mixture.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Paper, thin layer (TLC), and gas chromatography (GC) can all distinguish between pure and impure substances.
- Chromatographic processes use a mobile and stationary phase. TLC and GC both use silica/alumina as a stationary phase.
- Thin layer chromatography (TLC) uses locating agents to develop chromatograms and aid analysis of them.
- Chromatograms from gas chromatography (GC) also provide details about the amount of each component in a sample.
- Retention factors (Rf) and retention times both provide quantitative information about a sample's components.
Keywords
Stationary phase - A surface along which the solvent (and any dissolved components) travels. It does not move during chromatography.
Mobile phase - The movement of a solvent and any dissolved components of a sample along the stationary phase in chromatography.
Chromatogram - The resultant pattern of a sample’s components on the stationary phase after chromatography has been carried out.
Thin layer chromatography - A type of chromatography that uses a thin layer of an inert substance spread over an unreactive flat surface as the stationary phase and a liquid state substance for the mobile phase.
Gas chromatography - A type of chromatography that uses an inert substance packed into a coiled tube as the stationary phase and an unreactive/inert gas as the mobile phase.
Common misconception
Students sometimes struggle to understand how using different mobile and/or stationary phases affects the resulting chromatograms.
Perform chromatography of the same mixture using different mobile phases/stationary phases and discuss the pros/cons of each combination.
To help you plan your year 10 chemistry lesson on: Comparing types of chromatography: including gas chromatography, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 10 chemistry lesson on: Comparing types of chromatography: including gas chromatography, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 4 chemistry lessons from the Separating substances unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.
Equipment
Grass sample, propanone, capillary tube, dropping pipette, mortar and pestle, water, TLC plate, chromatography, 2x beaker, watch glass, paper, pencil, ruler.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
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Starter quiz
6 Questions
dissolves the solute(s)
furthest point reached by a solvent along the stationary phase
fixed medium through which a solvent, and components it contains, move
a liquid or gas that moves components it contains to separate them out
Exit quiz
6 Questions
helium is often used as the mobile phase
water is typically used as the mobile phase
volatile organic solvents are used as the mobile phase