These three tests are the lesser requested tests run on the same machine as the popular Total Organic Carbon (TOC) test.
To orient ourselves in the carbon spectrum, here are the variants of Carbon that we usually look at (list from Wikipedia, link below). MEL is certified to run tests in RED.
Total Carbon (TC) – all the carbon in the sample, including both inorganic and organic carbon
Total Inorganic Carbon (TIC) – often referred to as inorganic carbon (IC), carbonate, bicarbonate, and dissolved carbon dioxide (CO2).
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.
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.
Wikipedia: "Total Organic Carbon"
"Understanding Laboratory Wastewater Tests: Organics" , University of Georgia Extension (.pdf)
MEL Test Method for TC, TIC, DOC
Drinking Water, Wastewater - SM 5310B, 22nd ed. (SDWA, CWA, NPDES compliant)
aka EPA 9060A (SW-846) (RCRA compliant)
[Note: TC and TIC are not recognized for certification by the State of Maine.]
Container: plastic, glass (amber glass preferred)
Volume: 40 mL - fill to top
Hold Time: 28 days
Preservation: H2SO4 or HCl to pH <2; ≤6°C
Container: plastic, glass
Hold Time: 28 days