Preparation and standardization of 0.05 M Zinc Sulfate USP Volumetric Solution
Dissolve 14.4 g of Zinc sulfate in water to make 1000 mL.
Accurately measure about 10 mL of 0.05 M Disodium edetae VS into a 125 mL conical flask, and add, in the order given, 10 mL of Acetic acid-ammonium acetate buffer TS, 50 mL of alcohol and 2 mL of Dithizone TS. Titrate with the 0.05 M Zinc suifate solution to a clear, rose-pink color.
Molarity (M) = [Volume of Disodium edetate (in mL) x Molarity of Disodium edetate]/ [Titration Reading (in mL)]
Limit: 0.05 M ± 5 % (0.0475 M – 0.0525 M)
3. PREPARATION OF INDICATORS / REAGENTS :
a. 0.05 M Disodium Edetate VS :
Preparation and standardization as per Doc. Ref. No.: D/VS/USP/024.
b. Acetic acid-ammonium acetate buffer TS:
Dissolve 77.1 g of Ammonium acetate in water, add 57 mL of glacial Acetic acid, and dilute with water to 1000 mL.
c. Dithizone TS:
Dissolve 25.6 mg of Dithizone in 100 mL of alcohol. Store in a cold place, and use within 2 months.
4. STORAGE CONDITION :
Store in glass-stoppered bottles.