>Does anyone remember the identity of the blue-green pigment
>that is extracted from spinach with acetone and runs down with
>or below the xanthophylls when you separate pigments by TLC?
Kathy,
Sounds like it may be chlorophyllide. In a solvent and particularly
when also exposed to light, chlorophyll will lyse into chlorophyllide
and the phytol tail. Chlorophyllide is more polar and smaller than
chlorophyll and in TLC systems similar to yours (I've never used the
exact solvent you described in a subsequent post) it may appear below
the xanthophylls. Many students describe it as steely blue rather than
blue-green though that may very with the solvents and the amount of
light in the lab. Chlorophyllide seems to be more noticeable in TLC
than paper chromatography. One way to reduce the lysis might be to
reduce light levels during extraction and the run. Turning off
florescent lights seems to help and certainly avoid sunlight.
This is just one possibility. One person you may want to contact is
Alexander Motten at Duke University. He has written a lab exercise on
the separation of plant pigments using TLC and may well have an answer
for you. His email address is afmotten at acpub.duke.edu.
John Sowell jsowell at western.edu
Biology Department
Western State College
Gunnsion, CO 81231
