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Chromatography Separates Photosynthetic Pigments by Their Solubility
Definition
Chromatography
Chromatography is a technique used to separate and identify components of a mixture based on their differing affinities for a stationary phase and a mobile phase.
- Plant leaves contain several photosynthetic pigments mixed together.
- Chromatography separates them because each pigment has a different solubility in the solvent.
- Pigments also differ in how strongly they cling to the stationary phase, which affects how far they travel.
- Once separated, each pigment can be identified by its colour and its Rf value.
- In a leaf this typically reveals chlorophyll a, chlorophyll b, and carotenoids.
Tip
- Chromatography works because each pigment has its own combination of solubility and attraction to the stationary phase.
Every Chromatography Method Uses Two Phases
- Stationary phase: a fixed surface such as paper or a coated plate.
- Mobile phase: a solvent that moves through the stationary phase and carries the pigments with it.
- As the solvent moves, it dissolves the pigments and carries them along.
- More soluble pigments travel farther, while pigments that cling to the stationary phase move more slowly.
Tip
- Pigments that are more soluble in the solvent travel farther up.
- Pigments with a stronger attraction to the stationary phase move more slowly.
Two Setups Are Commonly Used: Paper and Thin-Layer
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- C1.3.4 Separation and identification of photosynthetic pigments by chromatography
- C1.3.5 Absorption of specific wavelengths of light by photosynthetic pigments
- C1.3.6 Similarities and differences of absorption and action spectra