1.1 This test method covers the determination of total carbon (TC), inorganic carbon (IC), total organic carbon (TOC), dissolved organic carbon (DOC), and non-purgable organic carbon (NPOC) in drinking water, groundwater, surface water, wastewater, and seawater in the range from 0.5 mg/L to 50 mg/L. Concentrations of 50–4000 mg/L of carbon may be determined by automated injection of less sample volume or by sample dilution. Alternatively, use less sample volume and calibrate at higher concentrations.. 1.2 The sample is injected into a tube heated at ≥680ºC. The sample converts into a gaseous phase and forced through a layer of catalyst ensuring conversion of all carbon containing compounds to CO2. A non-dispersive infrared (NDIR) detector measures the resulting CO2. 1.3 For TOC and DOC analysis a portion of the sample is injected to determine TC or dissolved carbon (DC). A portion of the sample is then acidified and purged to remove the IC. The purged inorganic carbon is measured as TIC, or DIC. TOC or DOC is calculated by subtracting the inorganic fraction from the total carbon:

1.4 For NPOC analysis a portion of sample is acidified and purged to remove IC. The purged sample is then injected to determine NPOC. 1