- 57-13-6
- CH4N2O
| Test Items | superior quality | First grade |
| Nitrogen content (dry basis) / % | ≥46.3 | ≥46.3 |
| Biuret / % | ≤0.5 | ≤0.9 |
| Water / % | ≤0.3 | ≤0.5 |
| Iron (Fe) / % | ≤0.0005 | ≤0.0005 |
| Sulfate (SO42 -) / % | ≤0.005 | ≤0.01 |
| Alkalinity (in NH3) / % | ≤0.01 | ≤0.01 |
| Water insoluble / % | ≤0.005 | ≤0.01 |