| Meets A.C.S. Specifications |
| Meets Reagent Specifications for testing USP/NF monographs |
| Appearance Passes Test |
| Assay (Na2SO3) (by iodometry) min. 98.0 % |
| Insoluble Matter max. 0.005 % |
| Free Acid Passes Test |
| Titrable Free Base (meq/g) max. 0.03 |
| Chloride (Cl) max. 0.02 % |
| Heavy Metals (as Pb) max. 0.001 % |
| Trace Impurities (in ppm): |
| Iron (Fe) max. 5 |
| \ |