Item

USP26

EP

GB

Identification

infrared

infrared or chemical method

infrared or chemical method

pH (5% aqueous solution)

5.5～9.5

6.5～8.5

5.5～9.5

Specific optical rotation

－29o～－32o

－29o～－32o

－29o～－32o

Water content

≤4%

≤1%

≤4%

Purity

97～103%

98～102%

97～103%

Sodium

≤0.1%

≤0.1%

Potassium

≤0.2%

Heavy metal (base on Pb)

≤0.002%

≤0.001%

≤0.001%

Arsenic

≤0.0002%

≤0.0002%

Chloride

≤0.40%

≤0.20%

≤0.40%

Residue on ignition

≤0.5%

Cyanogen

not detected

Clarity of solution

impurity A ≤0.5%