Description White to pale yellow crystalline powder. Odorless or has a slight ,characteristic odor.Identity Conforms the test pH 2.8~3.8Specific Rotation -76°~-88°Water Content 9.0%~11.5%Residue of ignition Not more than 0.2%Heavy Metals Not more than0.0020% Related Substances Not more than2.5%Assay 96.5%~102.0% (Calculated on anhydrous substance)