Packaging and storage—
Preserve in tight, light-resistant containers.
Identification—
B:
Add 1 mL of 0.1 N hydrochloric acid to 4 mL of a solution (1 in 50): the solution reduces alkaline cupric tartrate TS slowly at room temperature but more readily upon heating.
C:
A solution (1 in 50) responds to the tests for
Sodium 
191
.
Specific rotation 781S:
between +103
and +108
, determined immediately following the preparation of the solution.
Test solution:
100 mg per mL, in carbon dioxide-free water.
pH 791:
between 7.0 and 8.0, in a solution (1 in 10).
Loss on drying 731—
Dry it in a suitable vacuum drying tube, phosphorus pentoxide being used as the desiccant, at 60
for 4 hours: it loses not more than 0.25% of its weight.
Heavy metals, Method II 231:
0.002%.
Organic volatile impurities, Method I 467:
meets the requirements.
Assay—
Dissolve about 400 mg of Sodium Ascorbate, accurately weighed, in a mixture of 100 mL of carbon dioxide-free water and 25 mL of 2 N sulfuric acid. Titrate immediately with 0.1 N iodine VS, adding 3 mL of
starch TS as the endpoint is approached. Each mL of 0.1 N iodine is equivalent to 9.905 mg of C
6H
7NaO
6.
;)
