|
Appearance
|
A white crystalline powder
|
|
Assay (acidimetric)
|
99.5 - 103%
|
|
Identity
|
Passes test
|
|
Clarity of solution
|
Passes test
|
|
Insoluble matter
|
Max 0.005%
|
|
pH (0.01 M solution; 25°C)
|
9.15 - 9.20
|
|
pH (4% solution in water)
|
9.0 - 9.6
|
|
Chloride (Cl)
|
Max 0.0007%
|
|
Phosphate (PO4)
|
Max 0.001%
|
|
Sulphate (SO4)
|
Max 0.005%
|
|
Heavy metal (as Pb)
|
Max 0.001%
|
|
Arsenic (As)
|
Max 0.0005%
|
|
Calcium (Ca)
|
Max 0.005%
|
|
Copper (Cu)
|
Max 0.0005%
|
|
Iron (Fe)
|
Max 0.0005%
|
|
Ammonium (NH4)
|
Max 0.001%
|
|
Lead (Pb)
|
Max 0.0005%
|