preparation of flower pigments

This is one of the first methods described to prepare larger quantities of the water soluble flower pigments of Antirrhinum majus in pure form. It dates from 1912, long before chromotography or thin-layer methods came into use.
  1. Boil collected flowers or partial flowers (upper lips, lower lips, bumps etc.) with water. The pigments are water soluble.
  2. Filter the extract through large funnels into lixiviating jars
  3. Add solid crystalline lead acetate to precipitate the pigments until no further precipitation occurs.
  4. Let stand for a few hours.
  5. Decant.
  6. Filter through a Buchner funnel attached to a filter pump.
  7. Add 5-10% sulphuric acid. This forms lead sulphate.
  8. Filter off the lead sulphate. Filtrate contains the pigments as glucosides in dilute sulphuric acid solution.
  9. Boil for several hours in Jena flasks fitted with tube condensers. Don't concentrate!
  10. Cool and let stand 12 hours. Pigment deposits.
  11. Filter through a small Buchner funnel using a Geryk pump.
  12. Wash.
  13. Dry in desiccator over sulphuric acid.
Taken from Wheldale M. 1913