Separating plant pigments Chromatography Separating plant pigments
Cellulose Paper (stationary phase)
Ethanol Solvent (mobile phase)
Chromatography It is possible to measure the solubility of a pigment in a solvent by measuring how far the pigment travels vs. how far the solvent travels This is called retention factor, or Rf value Rf values are characteristic of specific pigments and can be used to identify them The higher the Rf value, the less polar the compound. Thus, a compound not migrating from the origin would have an Rf of 0, a compound migrating with the solvent front would have an Rf of 1.0, and a compound migrating half as far as the solvent front would have an Rf of 0.5.
Plant Pigments
Rf values of pigments Carotene - 0.98; orange Pheophytin - 0.81; olive green Chlorophyll a - 0.59; blue-green Chlorophyll b - 0.42; yellow-green Anthocyanins - between 0.32 and 0.62; red, pink, purple and blue colors Xanthophyll 1 - 0.28, yellow Xanthophyll 2 - 0.15, yellow