Dissolved organic carbon
The dissolved organic carbon or engl. Dissolved organic carbon ( DOC ), as part of the total organic carbon, is one of the total carbon parameters and describes the dissolved forms. It is part of the dissolved organic matter ( DOM ). Such particles are smaller than 0.45 µm .
LC-OCD - Liquid Chromatography - Organic Carbon Detection
The LC-OCD is a liquid chromatography system which contains a carbon-selective detector in addition to standard detectors such as UV / Vis (UV), fluorescence (FL) and conductivity (LF).
The DOC is determined with the Gräntzel thin-film reactor , in which organic carbon is converted to carbon dioxide (CO 2 ) by wet chemical oxidation using UV radiation (185 nm) without the addition of an oxidizing agent . The sample flows as a thin film over a cylinder and is intensely irradiated with UV light . At the same time, the sample film is stirred by a rotating inner cylinder equipped with Teflon pins. This results in a largely quantitative oxidation of the organic carbon compounds. Dilute phosphoric acid ( pH 2) is added to the sample in the upper, non-irradiated part of the reactor . The carbon dioxide thus formed from the IC is continuously stripped out with nitrogen . The carbon dioxide is detected with an IR detector .
The process was developed between 1985 and 1995 at the Engler-Bunte-Institute of the University of Karlsruhe together with the company Alfred Gräntzel - physical device construction in Karlsruhe .