Red Glow of Chlorophyll

One half of a filter paper is soaked with a β–carotene solution in heptane, the other half with chlorophyll extace in ethanol. The filter paper prepared in this way is observed in daylight and in the UV light of an LED flashlight.

• In daylight the β–carotene solution appears yellow, the chlorophyll solution grenn. In the UV light the chlorophyll solution glows red, the β–carotene solution doesn't luminesce at all.

This Video demonstrates an experiment showing the photoprotection of chlorophyll by β-Carotene. For this pumpkin seed oil is mixed 1:1 with acetone and applied to a filter paper. Under irradiation with UV light the chlorophyll shows an intensive red fluorescence.

After applying β-carotene solution in heptane to a small point on the filter paper, the fluorescence of the chlorophyll is reduced. In the next step the filter paper is irradiated in a large area around the spot with the β-carotene solution. The fluorescence of the chlorophyll in this area is almost completely gone, only the spot that had β-carotene applied to it shows the same fluorescence as before the filter paper was irradiated.