| White crystalline matter | Complying |
| Assay (T dry) | 98-102%w/w |
| Chloride (Cl) | max. 0.0005% |
| Heavy metals (as Pb) | max. 0.0005% |
| Iron (Fe) | max. 0.0005% |
| Nitrate (NO3) | max. 0.001% |
| Sulfate (SO4) | max. 0.001% |
| pH (5% in water) | 6.7-7.3 |
| Residue after ignition | max. 0.01% |
| Water insolubles | max. 0.005% |