Assay—
Transfer about 250 mg of Potassium Guaiacolsulfonate, accurately weighed, to a 500-mL volumetric flask, dissolve in 400 mL of water, dilute with water to volume, and mix. Dilute 10.0 mL of this solution with pH 7.0 phosphate buffer to 100.0 mL, and mix. Concomitantly determine the absorbances of this solution and a Standard solution of
USP Potassium Guaiacolsulfonate RS in the same medium, having a known concentration of about 50 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 279 nm, with a suitable spectrophotometer, using a 1 in 10 mixture of water and pH 7.0 phosphate buffer as the blank. Calculate the quantity, in mg, of C
7H
7KO
5S in the Potassium Guaiacolsulfonate taken by the formula:
5C(AU / AS),
in which
C is the concentration, in µg per mL, calculated on the anhydrous basis, of
USP Potassium Guaiacolsulfonate RS in the Standard solution, and
AU and
AS are the absorbances of the preparation under assay and the Standard solution, respectively.
;)
191
.
for 18 hours.