Adblue urea is an aqueous urea solution made with urea ,water and other chemicals, also its called diesel exhaust fluid. This solution used as a consumable in selective catalytic reduction (SCR) in order to lower NOx concentration in the diesel exhaust emissions from diesel engines. Buyformula website will teach you the best method for making automobile  adblue urea solution. Formulas are available in PDF format file, that described in technical English language.