Sodium Thiosulfate

Sodium Thiosulfate USP Grade Specifications

Na2S2O3-5H2O -- 248.19Sodium 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%.