Appearance of solution: 1.0g is dissolved in 10ml water. The solution should be clarified, and the color of the closest colorimetric solution should not exceed no. 6 color (equivalent to no. 1 color of Chinese pharmacopoeia).
PH: 1.0g dissolved in 10ml water with co2 removed. PH 6.2 7.7.
Characteristic absorption: 50.0mg dissolved in 100ml 0.01m hydrochloric acid. At the wavelength of 231nm, 14-20 after drying.
Benzene methanol residue: no more than 0.1%(m/m)
Sodium content: 11.3-13.5 after drying.