REAGENTS: Sodium hydroxide Solution (1 in 5): Dissolve 2 g of sodium hydroxide in 10 mL of purified water. 2N Sulfuric acid : Add slowly, with stirring, 60 mL of sulfuric acid to about 1020 mL of purified water, allow to cool to 25°C.6 7N Sulfuric acid : Add slowly, with stirring, 210 mL of sulfuric acid to about 1020 mL of purified water, allow to cool to 25°C. Potassium Iodide TS: Dissolve 16.5 g of potassium iodide in purified water to make 100 mL.
Store in light-resistant containers. Stronger acid Stannous Chloride, TS: Dissolve 8 g of stannous chloride in 20 mL of hydrochloric acid. Store in glass containers, and use within 3 months. Silver diethyldithiocarbamate TS: Dissolve 1 g of silver diethyldithiocarbamate in 200 mL of pyridine from a freshly opened bottle or that which has been recently distilled. Store in light-resistant containers, and use within 30 days. Arsenic Trioxide Stock Solution: Dry arsenic trioxide at 105°C for 1 hour. Weigh accurately 132.0 mg into 1000 mL volumetric flask and dissolve in 5 mL of Sodium hydroxide solution (1 in 5).
Neutralize the solution with a 2N Sulfuric acid, add 10 mL more of 2N sulfuric acid, then add recently boiled and cooled purified water to volume, and mix. Standard Arsenic Solution: Transfer 10.0 mL of Arsenic Trioxide Stock Solution to a 1000 mL volumetric flask, add 10 mL of 2N Sulfuric acid, then add recently boiled and cooled purified water to volume, and mix. Each mL of Standard Arsenic solution contains the equivalent of 1 µg of arsenic (As). Keep this solution in an all-glass container, and use within 3 days.
ARSENIC, General Testing Procedure, purified water
Store in light-resistant containers. Stronger acid Stannous Chloride, TS: Dissolve 8 g of stannous chloride in 20 mL of hydrochloric acid. Store in glass containers, and use within 3 months. Silver diethyldithiocarbamate TS: Dissolve 1 g of silver diethyldithiocarbamate in 200 mL of pyridine from a freshly opened bottle or that which has been recently distilled. Store in light-resistant containers, and use within 30 days. Arsenic Trioxide Stock Solution: Dry arsenic trioxide at 105°C for 1 hour. Weigh accurately 132.0 mg into 1000 mL volumetric flask and dissolve in 5 mL of Sodium hydroxide solution (1 in 5).
Neutralize the solution with a 2N Sulfuric acid, add 10 mL more of 2N sulfuric acid, then add recently boiled and cooled purified water to volume, and mix. Standard Arsenic Solution: Transfer 10.0 mL of Arsenic Trioxide Stock Solution to a 1000 mL volumetric flask, add 10 mL of 2N Sulfuric acid, then add recently boiled and cooled purified water to volume, and mix. Each mL of Standard Arsenic solution contains the equivalent of 1 µg of arsenic (As). Keep this solution in an all-glass container, and use within 3 days.
ARSENIC, General Testing Procedure, purified water
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