1. Orcein and other lichen dyes have largely been replaced by synthetic versions.2. Often orcein or a combination of resorcinol and fuchsine are used for staining. 3. The chemical components of orcein were elucidated only in the 1950s by Hans Musso. 4. Orcein is a reddish-brown dye, orchil is a purple-blue dye.5. It is especially useful today for staining chromosomes in plant or animal tissues, as a replacement for Aceto-orcein stain. 6. Oxidation of the ammoniacal solution gives orcein , C 28 H 24 N 2 O 7, the chief constituent of the natural dye archil. 7. Orcein is also used as a stain in microscopy to visualize chromosomes, elastic fibers, Hepatitis B surface antigens, and copper-associated proteins.8. I'd like to do this experiment with my students in high school, but I can't get my hands on any orcein . 9. It is used in the production of the dye orcein and as a reagent in some chemical tests for pentoses, such as Bial's Test. 10. Orcein is not approved as a food dye ( banned in Europe since January 1977 ), with E number E121 before 1977 and E182 after ., Its CAS number is.
