Commercially available Alcian Blue (EMS #10350) contains about 49% dye; the remaining constituents are boric acid, sulphates, dextrin, and other unknown organic substances. It can be purified by the following method, presented by McAuliffe. W.G. McAuliffe (1983) - A Note on the Purification of Alcian Blue. Stain Technology, 58, pg 374.
The above method yields Alcian Blue containing about 78.7-83.5% dye, depending on the commercial source.
Hayat, M. A. (Ed.). (1989). Principles and Techniques of Electron Microscopy. Third