质量标准
≥99.0% (T):
外观appearance white crystalline powder
水溶性solubility clear colorless solution at 15g plus 85ml of water
红外光谱Infrared spectrometry Conforms to Structure
水分water by karl fischer ≤ 1%
紫外吸收uv absorbance ≤ 0.05 at 290nm (15% w/w)
重金属heavy metals ≤ 5 ppm (as lead)
纯度purity by NaOH titration ≥ 99%
note * (anhydrous basis)
≥99.5% (T):
外观appearance white crystalline powder
红外光谱Infrared spectrometry Conforms to Structure
纯度Purity ≥99.5% (T)
insoluble matter, passes filter test
ign. residue ≤0.05%
loss on drying, 110 °C ≤0.5%
pH 3.0-5.0 (25 °C, 0.5 M in H2O)
useful pH range 8.6 - 10.0
pKa (25 °C) 9.3
水溶性solubility H2O: soluble0.5 M at 20 °C, clear, colorless
氯chloride (Cl-): ≤50 ppm
sulfate (SO42-): ≤500 ppm
Al: ≤5 ppm
As: ≤0.1 ppm
Ba: ≤5 ppm
Bi: ≤5 ppm
Ca: ≤10 ppm
Cd: ≤5 ppm
Co: ≤5 ppm
Cr: ≤5 ppm
Cu: ≤5 ppm
Fe: ≤5 ppm
K: ≤50 ppm
Li: ≤5 ppm
Mg: ≤5 ppm
Mn: ≤5 ppm
Mo: ≤5 ppm
Na: ≤50 ppm
Ni: ≤5 ppm
Pb: ≤5 ppm
Sr: ≤5 ppm
Zn: ≤5 ppm
λ 0.5 M in H2O
UV absorption λ: 260 nm A: ≤0.08
λ: 280 nm A: ≤0.05