| Standards | The standards of China state drug administration |
| Appearance | white or off-white powder |
| Melting point | 88.5?~93.5 |
| Physicochemical reaction | Reaction was positive |
| UV | Strong absorbability in 262nm wavelength |
| Acidity value | Pink when it reacts with 0.1mol/L NaOH |
| Related compounds | Impurity spot is not stronger than main spot in reference standard solution |
| Loss On Drying | 0.5% max. |
| Residue On Ignition | 0.1% max. |
| sulfate | Accords with the spesification |
| Heavy Metals | 20ppm |
| Assay | 98.5% min. on dry basis |