TOC refers to a Total Organic Carbon analyzer, which utilizes a catalytic oxidation combustion technique at high temperature (the temperature raises up to 720 ºC), to convert organic carbon into CO 2 . The CO 2  generated by oxidation is measured with a Non-dispersive Infra-Red (NDIR) sensor. TOC is the measure of the level of organic molecules or contaminants in purified water. TOC is an analytic technique that helps organizations understand whether the water they are using is pure enough for their processes.Shimadzu Total organic carbon analyzers measure the amount of organic, inorganic,or total carbon in water samples. TOC is an important indicator of disinfection byproducts and the byproduct rule requires drinking water facilities to measure TOC removal. Analyze TOC by removing all the inorganic carbon and measuring NPOC, or calculate by subtracting inorganic carbon from total carbon. The subtraction method is prone to error and most people actually just measure NPOC.