Method SM 5310B

Total Organic Carbon (TOC)


The high-temperature combustion method has been used for a wide variety of samples, but its utility is dependent on particle size reduction because it uses small-orifice syringes. 

The sample is homogenized and diluted as necessary and a microportion is injected into a heated reaction chamber packed with an oxidative catalyst such as cobalt oxide, platinum group metals, or barium chromate. The water is vaporized and the organic carbon is oxidized to CO2 and H2O. The CO2 from oxidation of organic and inorganic carbon is transported in the carrier-gas streams and is measured by means of a nondispersive infrared analyzer, or titrated coulometrically.

Because total carbon is measured, inorganic carbon must be removed by acidification and sparging or measured separately and TOC obtained by difference. Measure inorganic carbon by injecting the sample into a reaction chamber where it is acidified. Under acidic conditions, all inorganic carbon is converted to CO2, which is transferred to the detector and measured. Under these conditions organic carbon is not oxidized and only inorganic carbon is measured. Alternatively, convert inorganic carbonates to CO2 with acid and remove the CO2 by purging before sample injection. The sample contains only the nonpurgeable organic carbon fraction of total carbon: a purgeable organic carbon determination also is necessary to measure TOC.

-Standard Methods Online — Standard Methods for the Examination of Water and Wastewater

Method Data

Method 5310 B
Hold Time
Sample Volume
Collection Method
Method Refernce

Analyte Test

Analyte Formula CAS Number

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