Sodium Thiosulfate

Sodium Thiosulfate USP Grade Specifications Na2S2O3-5H2O -- 248.19 Sodium Thiosulfate USP Contains not less than 99.0 percent and not more than 100.5 percent of Na2S2O3, calculated on the anhydrous basis. Packaging and storage— Preserve in tight containers. Identification— A: To a solution (1 in 10) add a few drops of iodine TS: the color is discharged. B: A solution (1 in 10) responds to the tests for Sodium and for Thiosulfate. Water— Dry about 1.0 g, accurately weighed, in vacuum at 40 o to 45o for 16 hours: it loses between 32.0% and 37.0% of its weight. Calcium— Dissolve 1 g Sodium Thiosulfate in 20 mL of water, and add a few mL of ammonium oxalate TS: no turbidity is produced. Heavy metals—: the limit is 0.002%.