[danavuia.1987]

When i make this analyze in my lab :
the ammonium nitrogen is 22 mg/l.
I don,t have the possibility to make total nitrogen.
This analyzes made by control authority:
Ammonium nitrogen around 30 mg/l and total nitrogen around 25 mg/l.

What i know is that the total nitrogen=ammonium nitrogen+nitrate nitrogen+nitrite nitrogen+organic nitrogen.
I know that when an sample is taken for ammonium nitrogen is taken , in the sampe must be introduced 2 ml of H2S04 conc. because the H2SO4 can reduce the conversion of organic-N to ammonium.

This may be the cause of the results : ammonium nitrogen bigger than total nitrogen(conversion of organic nitrogen to ammonium in the time of sample transport to the control authority)?

Sorry for my english.

[chenbeier]

There must be something wrong. Total means the sum of all nitrogen. Any individual nitrogen (Ammonium, nitrate, etc.) has to be smaller than total.