Impurities : org. volatile impurities, complies (GC)  
   residual solvents, complies  
   ≤0.001% heavy metals (as Pb)
   ≤0.04% KMnO₄ red. matter (as O)
   ≤0.2% in water insoluble matters
Loss : ≤1% loss on drying, 130°C
pH : 4.2-4.5 (20°C, 5%)
pKa : (25 °C)    (1) 2.15, (2) 6.82, (3) 12.38 (phosphoric acid)
mp = 252.6°C (lit.)  
Solubility :
 H₂O: soluble 4.5 parts
 alcohol: insoluble
Density : 2.338 g/mL at 25°C (lit.)
Anion traces :
 chloride (Cl^-): ≤ 10 mg/kg
 fluoride (F^-): ≤ 10 mg/kg
 sulfate (SO₄^2-): ≤ 200 mg/kg
Cation traces :
 As: ≤ 2 mg/kg
 Cd: ≤ 1 mg/kg
 Cu: ≤ 20 mg/kg
 Fe: ≤ 10 mg/kg
 Hg: ≤ 1 mg/kg
 Na: ≤ 1000 mg/kg
 Pb: ≤ 4 mg/kg
 Zn: ≤ 20 mg/kg.