TOC analysis is a key technique for assessing the amount of organic matter present in water in industries where continuous water monitoring is essential for quality control, environmental protection, and operational efficiency.
One widely used method employs a high-temperature combustion process, where the sample water is continuously injected into a furnace operating typically at temperatures of 850 °C. In this environment, organic carbon compounds are quantitatively oxidized to carbon dioxide (CO₂) in the presence of oxygen and catalyst. The resulting CO₂ is then transported with a carrier gas through a drying stage into an NDIR detector, which quantifies the carbon content. Additionally, the total bound nitrogen (TNb) can be determined by measuring the nitric oxide (NO) concentration.
Typical applications of this method include monitoring the wastewater treatment stages in sewage and industrial wastewater treatment plants, monitoring drinking and process water, as well as monitoring surface water of airports and refineries.
Online TOC analysis systems must comply with the standard test methods defined in DIN EN 1484 for measuring organic carbon in drinking water, groundwater, surface water, seawater, and wastewater. This standard specifies the quantification of total (TC), organic (TOC), inorganic (TIC) or dissolved organic carbon (DOC) content in water samples in the concentration range of 0.3 mg/l to 1,000 mg/l. For the optional determination of total bound nitrogen (TNb), DIN 38409 Part 27 for TNb determination applies.