Total carbon (TC) is the sum of carbon species, an analytical measurement of total carbon content commonly used in environmental and pharmaceutical analysis.
Forms of carbonEdit
A variety of different terms are used to identify the different forms of carbon present at different levels of detail.
- Total carbon (TC) – all the carbon in the sample, including both inorganic and organic carbon
- Carbon compounds can be distinguished as either organic or inorganic, depending on their composition. Organic carbon forms the backbone of key component of organic compounds such as – proteins, lipids, carbohydrates, and nucleic acids. Inorganic carbon is found primarily in simple compounds such as carbon dioxide, carbonic acid, bicarbonate, and carbonate (CO2, H2CO3, HCO3−, CO32− respectively).
- Volatile organic compounds (VOC) – also referred to as purgeable organic carbon (POC); organic carbon that has been removed from a neutral, or acidified sample by purging with an inert gas. These are usually determined by purge and trap gas chromatography–mass spectrometry.
- Non-purgeable organic carbon (NPOC) – commonly referred to as TOC; organic carbon remaining in an acidified sample after purging the sample with gas.
- Marine carbon is further separated into particulate and dissolved phases. These pools are operationally defined by physical separation – dissolved carbon passes through a 0.2 μm filter, and particulate carbon does not.
- Dissolved inorganic carbon (DIC) – inorganic carbon remaining in a sample after filtering the sample, typically using a 0.45 micrometer filter.
- Particulate inorganic carbon (PIC) – also called suspended inorganic carbon; the inorganic carbon in particulate form that is too large to pass through the filter.
- Schumacher, B. A. (2002). "Methods for the Determination of Total Organic Carbon (TOC) in Soils and Sediments" Ecological Risk Assessment Support Center. US. Environmental Protection Agency 23p.