Sodium disulfite, Pharmpur®, Ph Eur, BP, NF

- Synonyms: Sodium metabisulfite, Sodium pyrosulfite
- Na2S2O5
- M = 190,10 g/mol
- CAS [7681-57-4]
- EINECS-No.: 231-673-0
- Solub. in water: (20 ºC): ~ 650 g/l
- Melting point: ~ 150 ºC (decomposes)
- LD 50 (oral, rat): 1540 mg/kg
- GHS-signal word: Danger
- GHS-H sentences: H318 - H302 - EUH031
- GHS-P sentences: P280 - P264 - P305+P351+P338 - P310 - P301+P312 - P501a
- Tariff number: 2832 10 00 00
- Applications: analytical chemistry, laboratory reagent, bleaching agent, reducing agent (manufacture of dyes), antioxidant (in the pharmaceutics industry), in food industry (E 223), preservative agent.

SPECIFICATIONS
assay (iodometric): 95,0 - 100,5 %
assay (iodometric, as SO2): 65,0 - 67,4 %
identification: passes test
Identification sodium: passes test:
reaction of sulphates: passes test:
appearance of solution: clear and colourless
pH (5 %, H2O): 3,5 - 5,0
chlorides (Cl): max. 0,05 %
thiosulfates (S2O3): max. 0,05 %
thiosulfates (S2O3): passes test
arsenic (As): max. 5 ppm
iron (Fe): max. 20 ppm