5 There are four pigments that you will separate from spinac

5. There are four pigments that you will separate from spinach this week: chlorophyll-a, chlorophyll-b xanthophylls, and carotene. What color will the bands for these pigments be? Chlorophyll-a Xanthophylls The polarity for each of these compounds relative to the silica stationary phase is... Chlorophyll-a: Polar Slightly polar Slightly non-polar Non-polar Chlorophyll-: Polar Slightly polar Slightly non-polar Non-polar Xanthophylls: Polar Slightly polar Slightly non-polar Non-polar Carotene 6. Polar Slightly polar Slightly non-polar Non-polar Carotene: In what order would you expect to find these pigments on the TLC plate (from least to greatest distance travelled)? 7.

Solution

5. Chlorophyll-a: Blue-green, Chlorophyll-b: Yellow-green, Xanthophylls: Yellow, Carotene: Yellow-orange

6. Polarity order is:

Chlorophyll-b > Chlorophyll-a > Xanthophylls > Carotene

Chlorophyll-b contains extra -CHO group compare to Chlorophyll-a that contains -CH3 instead making Chlorophyll-b more polar. Carotene is most nonpolar because of the presence of conjugate alkene system. Xanthophylls are slightly non-polar.