Reagents: Test Solutions
Ferric Chloride TS —Dissolve 9 g of ferric chloride in water to make 100 mL.
Thioacetamide TS —Dissolve 4 g of thioacetamide in 100 mL of water.
Thioacetamide–Glycerin Base TS —Mix 0.2 mL of thioacetamide TS and 1 mL of glycerin base TS, and heat in a boiling water bath for 20 seconds. Use the mixture immediately.
Lead Nitrate Stock Solution— Dissolve 159.8 mg of lead nitrate in 100 mL of water to which has been added 1 mL of nitric acid, then dilute with water to 1000 mL. Prepare and store this solution in glass containers free from soluble lead salts.
Standard Lead Solution— On the day of use, dilute 10.0 mL of Lead Nitrate Stock Solution with water to 100.0 mL. Each mL of Standard Lead Solution contains the equivalent of 10 µg of lead. A comparison solution prepared on the basis of 100 µL of Standard Lead Solution per g of substance being tested contains the equivalent of 1 part of lead per million parts of substance being tested.
pH 3.5 Acetate Buffer— Dissolve 25.0 g of ammonium acetate in 25 mL of water, and add 38.0 mL of 6 N hydrochloric acid. Adjust, if necessary, with 6 N ammonium hydroxide or 6 N hydrochloric acid to a pH of 3.5, dilute with water to 100 mL, and mix
Hydrochloric Acid, Normal (1 N)
HCl, 36.46
36.46 g in 1000 mL
Dilute 85 mL of hydrochloric acid with water to 1000 mL.
Sulfuric Acid, Normal (1 N)
H2SO4, 98.08
49.04 g in 1000 mL
Add slowly, with stirring, 30 mL of sulfuric acid to about 1020 mL of water, allow to cool to 25, and determine the normality by titration against tromethamine as described under Hydrochloric Acid, Normal (1 N).
Potassium Permanganate, Tenth-Normal (0.1 N)
KMnO4, 158.03
3.161 g in 1000 mL
Dissolve about 3.3 g of potassium permanganate in 1000 mL of water in a flask, and boil the solution for about 15 minutes. Insert the stopper in the flask, allow it to stand for at least 2 days, and filter through a fine-porosity, sintered-glass crucible. If necessary, the bottom of the sintered-glass
Thioacetamide TS —Dissolve 4 g of thioacetamide in 100 mL of water.
Thioacetamide–Glycerin Base TS —Mix 0.2 mL of thioacetamide TS and 1 mL of glycerin base TS, and heat in a boiling water bath for 20 seconds. Use the mixture immediately.
Lead Nitrate Stock Solution— Dissolve 159.8 mg of lead nitrate in 100 mL of water to which has been added 1 mL of nitric acid, then dilute with water to 1000 mL. Prepare and store this solution in glass containers free from soluble lead salts.
Standard Lead Solution— On the day of use, dilute 10.0 mL of Lead Nitrate Stock Solution with water to 100.0 mL. Each mL of Standard Lead Solution contains the equivalent of 10 µg of lead. A comparison solution prepared on the basis of 100 µL of Standard Lead Solution per g of substance being tested contains the equivalent of 1 part of lead per million parts of substance being tested.
pH 3.5 Acetate Buffer— Dissolve 25.0 g of ammonium acetate in 25 mL of water, and add 38.0 mL of 6 N hydrochloric acid. Adjust, if necessary, with 6 N ammonium hydroxide or 6 N hydrochloric acid to a pH of 3.5, dilute with water to 100 mL, and mix
Hydrochloric Acid, Normal (1 N)
HCl, 36.46
36.46 g in 1000 mL
Dilute 85 mL of hydrochloric acid with water to 1000 mL.
Sulfuric Acid, Normal (1 N)
H2SO4, 98.08
49.04 g in 1000 mL
Add slowly, with stirring, 30 mL of sulfuric acid to about 1020 mL of water, allow to cool to 25, and determine the normality by titration against tromethamine as described under Hydrochloric Acid, Normal (1 N).
Potassium Permanganate, Tenth-Normal (0.1 N)
KMnO4, 158.03
3.161 g in 1000 mL
Dissolve about 3.3 g of potassium permanganate in 1000 mL of water in a flask, and boil the solution for about 15 minutes. Insert the stopper in the flask, allow it to stand for at least 2 days, and filter through a fine-porosity, sintered-glass crucible. If necessary, the bottom of the sintered-glass