Preparation and standardization of 0.1 M Zinc Sulfate USP Volumetric Solution
Dissolve 28.8 g of Zinc sulfate in water to make 1000 ml.
Accurately measure about 10 ml of 0.1 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 0.1 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: 0.1 M ± 5 % (0.0950 M – 0.1050 M)
3. PREPARATION OF INDICATORS / REAGENTS :
a. 0.1 M Edetate disodium VS:
Preparation and standardization as per Doc. Ref. No.: D/VS/USP/018
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.