Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
A solution (1 in 20) responds to the tests for
Sodium 
191
.
Chloride 221—
A 1.0-g portion shows no more chloride than corresponds to 1 mL of 0.020 N hydrochloric acid (0.07%).
Sulfate 221—
A 2.0-g portion dissolved in boiling water shows no more sulfate than corresponds to 1 mL of 0.020 N sulfuric acid (0.05%).
Lead 251—
Dissolve 1.0 g in 25 mL of water: the limit is 0.001%.
Heavy metals, Method I 231—
Dissolve 1.0 g in 10 mL of water, add 6 mL of 3 N hydrochloric acid, and dilute with water to 25 mL: the limit is 0.002%.
Reducing substances—
Transfer 1.0 g to a 250-mL conical flask, dissolve in 10 mL of water, and add 25 mL of
alkaline cupric citrate TS. Cover the flask, boil gently for 5 minutes, accurately timed, and cool rapidly to room temperature. Add 25 mL of 0.6 N acetic acid, 10.0 mL of 0.1 N iodine VS, and 10 mL of 3 N hydrochloric acid, and titrate with 0.1 N sodium thiosulfate VS, adding 3 mL of
starch TS as the endpoint is approached. Perform a blank determination, omitting the specimen, and note the difference in volumes required. Each mL of the difference in volume of 0.1 N sodium thiosulfate consumed is equivalent to 2.7 mg of reducing substances (as dextrose): the limit is 0.5%.
Assay—
Transfer about 150 mg of Sodium Gluconate, accurately weighed, to a suitable conical flask, and dissolve in 75 mL of glacial acetic acid, warming if necessary to effect complete solution. Cool, add
quinaldine red TS, and titrate with 0.1 N perchloric acid VS to a colorless endpoint. Each mL of 0.1 N perchloric acid is equivalent to 21.81 mg of C
6H
11NaO
7.
;)
