ISO 2515:1973

Ammonium hydrogen carbonate for industrial use (including foodstuffs) — Determination of ammoniacal nitrogen content — Volumetric method after distillation

Specifies a titrimetric method consisting in distillation of the ammonia after displacement by an alkaline solution; absorption in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of an indicator. The absorption of the ammonia may also be carried out in an excess of boric acid solution. The titration, in this case, is carried out directly with a standard volumetric sulphuric acid solution.