ISO 1592:1977

Urea for industrial use — Determination of nitrogen content — Titrimetric method after distillation

The procedure is based on the catalytic conversion of nitrogen present in a test portion to ammonia by heating in concentrated sulphuric acid solution. Distillation and absorption of the ammonia in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of an indicator. – Replaces ISO Recommendation R 1592-1970.