Total Organic Carbon (TOC) – material derived from decaying vegetation, bacterial growth, and metabolic activities of living organisms or chemicals.
Elemental Carbon (EC) – charcoal, coal, and soot. Resistant to analytical digestion and extraction, EC can be a fraction of either TIC or TOC depending on analytical approach.[1]
Non-Purgeable Organic Carbon (NPOC) – commonly referred to as TOC; organic carbon remaining in an acidified sample after purging the sample with gas.
Purgeable (volatile) Organic Compound (VOC) – organic carbon that has been removed from a neutral, or acidified sample by purging with an inert gas. These are the same compounds referred to as Volatile Organic Compounds (VOC) and usually determined by Purge and Trap Gas Chromatography.
Dissolved Organic Carbon (DOC) – organic carbon remaining in a sample after filtering the sample, typically using a 0.45 micrometer filter.
Suspended Organic Carbon – also called particulate organic carbon (POC); the carbon in particulate form that is too large to pass through a filter.