a Standard: 32.5%(m/m).
b The unit "%(m/m)" is used to indicate
mass fraction of matter according to the
international standard.
c. Calculated without excluding ammonia ni-
trogen
e. Standard: 1.3829
d. Standard: 1,090 kg/m
3
Ingredient Unit
Item
Test method
MIN. MAX.
Urea
concentration
a
%(m/m)
b
31.8 33.2
ISO 22241-2 Annex Bc
ISO 22241-2 Annex Cc
Density (at 20°C
d
) kg/m
3
1,087 1,093 ISO 3675 or ISO 12185
Refractive index
(at 20°C
e
)
- 1.3814 1.3843 ISO 22241 2 Annex C
Ammonia alkalinity
%(m/m)
b
- 0.2 ISO 22241 2 Annex D
Biuret %(m/m)
b
- 0.3 ISO 22241 2 Annex E
Aldehyde mg/kg - 5 ISO 22241 2 Annex F
Insoluble matter
mg/kg - 20 ISO 22241 2 Annex G
Phosphate (PO
4
) mg/kg - 0.5 ISO 22241 2 Annex H
Calcium mg/kg - 0.5
ISO 22241 2 Annex I
Iron mg/kg - 0.5
Copper mg/kg - 0.2
Zinc mg/kg - 0.2
Chromium mg/kg - 0.2
Nickel mg/kg - 0.2
Aluminum mg/kg - 0.5
Magnesium mg/kg - 0.5
Sodium mg/kg - 0.5
Potassium mg/kg - 0.5
Identical equation
- Identical ISO 22241 2 Annex J