Total nitrogen, TotN/TNb/Total-N

Last changed: 18 February 2018

Note: Total nitrogen content has previously also been calculated as the sum of Kjeldahl nitrogen and the sum of oxidized nitrogen (nitrite and nitrate nitrogen.

Known issues in the databases

Read more about total nitrogen content analyses at the Department of Aquatic Sciences and Assessment in two assessment on our various methods for analysis of total nitrogen content: Wallman m.fl. 2009 and Wallman m.fl. 2011, both in Swedish.

Current method of measurement (combustion)

Valid since January 2007
Method: SS-EN 12260:2004
Instruments: Shimadzu TOC-VCPH with TNM-1 module and automatic sample changer ASI-V. The samples are treated with HCl. The nitrogen content is measured through chemoluminescence after catalytic oxidation into nitrogen oxides.
Note 1: Run on three identical instruments
Note 2: Since 2010-03, sample changer with built-in stirring function is used. 

Previous methods (nitrogen from persulphate)

2002-01 – 2006-12
Method: Swedish Standard SS-EN ISO 11905 modified for Traacs. Bran & Leubbe Method No. J-002-88 B.
Instrument: Technicon Traacs 800.
NB: Water samples conserved with H2SO4.

1998-07 – 2001-12
Method: SIS 02 81 31-1 modified for Traacs. Bran & Leubbe Method No. J-002-88 B.
Instrument: Technicon Traacs 800.
NB: Water samples conserved with H2SO4.

1997-01 – 1998-06
Method: Swedish Standard SIS 02 81 31 modified for Traacs. Bran & Leubbe Industrial Method 55010279A.
Instrument: Technicon Traacs 800.
NB: Water samples conserved with H2SO4.

1988-01 – 1996-12
Method: Swedish Standard SIS 02 81 31 (modified). Bran & Leubbe Industrial Method 55010279A.
Instruments: Technicon Traacs 800 with sample changer for 120 samples. Autoclave for influx of sample.
NB: Water samples conserved with HgCl2.


Contact
Page editor: Lars.Sonesten@slu.se