grade
SigmaUltra
assay
≥99.0% (titration)
total impurities
≤0.005% Phosphorus (P)
≤0.1% Insoluble matter
ign. residue
≤0.1%
pH
10.0-12.0 (20 °C, 1 M in H2O)
useful pH range
6.3 - 9.5
pKa (25 °C)
(1) 6.8, (2) 9.0
mp
164-165 °C(lit.)
solubility
H2O: 1 M at 20 °C, clear, colorless
anion traces
chloride (Cl-): ≤0.05%
sulfate (SO42-): ≤0.05%
cation traces
Al: ≤0.0005%
Ca: ≤0.0005%
Cu: ≤0.0005%
Fe: ≤0.0005%
K: ≤0.005%
Mg: ≤0.0005%
NH4+: ≤0.05%
Na: ≤0.005%
Pb: ≤0.001%
Zn: ≤0.0005%
abs.
A1M/260, H2O ≤0.1
A1M/280, H2O ≤0.05