This deep dive covers Paper Chromatography Method within Chromatography for GCSE Chemistry. Revise Chromatography in Chemical Analysis for GCSE Chemistry with 23 exam-style questions and 15 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 3 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
📄 Paper Chromatography Method
- Draw a pencil line near the bottom of the chromatography paper (the start line)
- Use a capillary tube to place a small, concentrated spot of sample on the start line
- Allow the spot to dry completely
- Pour solvent into a beaker to a depth of about 1 cm
- Place the paper so the bottom touches the solvent but the start line is above the solvent level
- Cover with a watch glass to prevent evaporation
- Wait for the solvent to rise — this is the solvent front
- Remove the paper when the solvent is near the top, and immediately mark the solvent front with pencil
- Allow to dry and measure distances
Critical Points
- Use pencil not pen — ink would dissolve and run with the solvent
- The start line must remain above the solvent, otherwise the sample dissolves directly into the beaker
- Keep sample spots small for clean, well-separated spots
Practice questions for Chromatography
What is the purpose of chromatography?
Explain how a chromatogram can be used to determine whether a substance is pure or a mixture.
Quick recall flashcards
What is chromatography?
A separation technique used to separate mixtures into their individual components based on different affinities for mobile and stationary phases
What does Rf stand for and what does it measure?
Rf = Retention factor. It measures how far a substance travels compared to the solvent (distance moved by substance ÷ distance moved by solvent)