calculating... - (Aug/18/2008 )

TEST SPECIFICATION

APPEARANCE WHITE TO OFF-WHITE POWDER

LOSS ON DRYING NOT MORE THAN 10%

FREE GLUCOSE NOT MORE THAN 0.1% BY ENZYMATIC ASSAY

TOTAL GLUCOSE MINIMUM 85% (DRIED BASIS)

* NOTE* BY ENZYMATIC ASSAY AFTER ACID HYDROLYSIS
DOCUMENT # G0885/01/03/01/2

Above is the desciption of the product named Glycogen from bovine liver type IX.

I am not very sure how can i prepare a stock of gly solution with 0.2M using this product. do the '85% dried basis information' affect the preparation? Since i'll use the solution as standard, it is quite important to me..and i'm afraid if i mistaken in calculating the mass.
how can i prepare it?

Glycogen is a variable length polymer. Presumably the solution you want is 200 mM of the monomer. You do have a problem, however, in that the powder has variable water of hydration. For accurate mass, you will probably have to dry the powder in a desiccator. If this is important, I would look at how others have done this. A sample heated to constant weight might be used to estimate the water present, but might not eliminate it all if it is tightly bound.

Thank you for the reply..