How LC-OCD works
LC-OCD stands for Liquid Chromatography - Organic Carbon Detection. (LC/DOC is another name for the same technique). Apart from OCD there are more detectors added, a UV-detector at 254nm (UVD) and an organic nitrogen detector (OND).
As ”LC-OCD-UVD-OND” would be too long we decided to keep the old name ”LC-OCD”.
The figure below shows the LC-OCD Model 8 system in outline.
Mobile Phase is pre-cleaned by UV-Oxidation in the DOCOX-reactor and pumped to an autosampler and then to the chromatographic column. The liquid enters the UV-detector (UVD) and then the Organic Carbon Detector (OCD). A side stream after UVD enters a special capillary UV-lamp (DONOX) and then a 2nd UV-Detector measuring at 220nm. Here, Dissolved Organic Nitrogen (DON) and ammonium is determined after conversion to nitrate in the DONOX reactor.