Total organic carbon, TOC

Last changed: 18 February 2018

The most common method (and which we use) is directing the sample across a hot catalyst, where the carbon is combusted into CO2, which is quantified. First, inorganic carbon is removed by acidification of the sample and expulsion of the resulting carbonic acid with CO2-free gas. The final step may also expel some volatile organic forms of carbon, but these usually constitute a negligible proportion of the TOC in surface waters. 

Known issues in the databases

Current method of measurement

Valid since January 2007
Method: Swedish Standard SS-EN 1484 1st ed.
Instruments: Shimadzu TOC-VCPH with TNM-1 module and automatic sample changer ASI-V. Water samples not conserved. Preparation treatment with HCL and CO2 expulsion. The sample is subsequently combusted and produced CO2 is measured using an NDIR detector.
Note 1: Runs on three identical instrument setups.
Note 2: Since 2010-03, sample changer with built-in stirring apparatus is used.

Previous methods

2004-01 – 2006-12
Method: Swedish Standard SS-EN 1484 1st ed.
Instrument: Shimadzu TOC 5050 with sample injector ASI-502. Water samples not conserved. Preparation treatment with HCl and measured using an NDIR detector.

1999-01 – 2003-12
Method: Swedish Standard SS 02 81 99.
Instrument: Shimazdu TOC 5050 with sample injector ASI-502. Water samples not conserved. Preparation treatment with HCl.

1987-01 – 1998-12
Method: Swedish Standard SS 02 81 99.
Instrument: Shimazdu TOC 500 with sample injector ASI-502.
NB: Water samples conserved with HgCl2 until 1996, with H2SO4 during the period 1997-1998.


Contact
Page editor: Lars.Sonesten@slu.se