How to Prepare Orcein Solution?

Orcein is used in form of a 1% solution in 45% acetic acid. This solution is prepared by pouring 55 mL boiling glacial acetic acid over 1 g orcein powder. The solution is cooled, 45 mL of distilled water added, and filtered. This solution is unstable and should be prepared fresh before use.

What is acetic Orcein used for?

Orcein is a reddish-brown dye, orchil is a purple-blue dye. Orcein is also used as a stain in microscopy to visualize chromosomes, elastic fibers, Hepatitis B surface antigens, and copper-associated proteins.

What exactly does acetic Orcein stain?

Aceto-orcein stain turns chromosomes a purple-red colour. This stain can be prepared from powder or purchased as solution; staining is best with freshly prepared stain as, over time, the stain precipitates and changes colour from a deep red or burgundy colour to a brownish colour.