Complaint
| Testing Item | Standard | Result |
| Appearance | White crystals or crystalline powder | White crystalline powder |
| Assay (on anhydrous basis) | 98.0% ~ 102.0% | 99.7% |
| Appearance of solution | Clear, not more intense than Y7 or GY7 | Clear, not more intense than Y7 |
| Appearance of solution | Clear, not more intense than Y7 | Conformss |
| PH | 2.7 ~ 3.3 | 3.2 |
| Water | ≤ 5.0% | 3.44% |
| Sulphates | ≤ 0.03% | <0.03% |
| Residue on ignition | ≤ 0.1% | 0.01% |
| Absorbance of solution | ≤ 0.025 | 0.012 |
| Limit of nitrate | No brown ring is produced at the junction of the two layers | No brown ring is produced at the junction of the two layers |
| Related compounds | ≤ 1.0% | 0.02% |
