AUS32 (AdBlue) Specifications. Product Properties for AdBlue as per the revised ISO22241 standard. Urea 32,5 % (approximate) solution dissolved within deionised water. As required by SCR equipped vehicles under the provisions of Emissions standards Euro IV (Euro4), Euro V (Euro5) & Euro VI (Euro6). Urea Content 31.8 33.2 % by weight Density at 20C 1.0870 1.0930 g/cm Refracting Index at 20C 1.3814 1.3843 Alkalinity as NH3 0.2 % Biuret 0.3 % Aldehyde 5 mg/kg Insolubles 20 mg/kg Phosphate (PO4) 0.5 mg/kg Calcium 0.5 mg/kg Iron 0.5 mg/kg Copper 0.2 mg/kg Zinc 0.2 mg/kg Chromium 0.2 mg/kg Nickel 0.2 mg/kg Aluminium 0.5 mg/kg Magnesium 0.5 mg/kg Sodium 0.5 mg/kg Potassium 0.5 mg/kg