[Histonet] Alcian Blue Quality Control

[JR R]

I have used Alcian Blue 8GX from Sigma for years with pretty good results.  But I have had some variations in staining lately and noticed that the powder in the new lot isn't quite as dark as the previous lot.  Finally, I noticed that Sigma only guarantees the product to be have a dye content of "at least" 50%.
 

I would like to try to assay the dye content myself, so I could make my solutions to the sane strength every time.    Sigma says they don't know hw, they have no idea what the molar extinction coefficient of the compound is, and they refuse to tell me the name of the lab that does the QC.
 

The only thing I know is that it has a major absorbance peak at 610 nm.

Oh, rumor says there was an aticle about it in Histochemie back in 1972.

Any ideas?

Jerry Ricks
Research Scientist
University of Washington
Department of Pathology
 
 
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