Assay
Transfer to a suitable container an accurately measured volume of Injection, containing about 1 g of sodium thiosulfate, and adjust by the addition of 3 N hydrochloric acid to a pH of between 6.2 and 6.7. Dilute with water to about 20 mL, and titrate 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 24.82 mg of Na
2S
2O
3·5H
2O.