... per the buyer's requirement. Specification For Food Grade and Industry Grade : ItemQuality IndexFood GradeIndustry GradePurity ( As Na2S2O5)98 ... wearproof dose; sewage treatment, and so on .(3) Pharmaceutical Grade: In chemical synthesis in the production of acrylic fibre, ... vitamin K, vitamin A, pharmaceutical intermediates, etc.(4) Photo Grade: The sensitize industry is served as the ...