ASTM International

Standard Test Method for Total Carbon and Organic Carbon in Water by High Temperature Catalytic Combustion and Infrared Detection
 N D7573

Annotation

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 water, wastewater, and seawater in the range from 0.5 mg/L to 4000 mg/L of carbon. Higher levels may be determined by sample dilution. The sample is injected onto a quartz bed heated at 680?C. 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.

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: TOC5 TC2 IC

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

This test method was used successfully with reagent water spiked with potassium hydrogen phthalate, sucrose, nicotinic acid, benzoquinone, sodium dodecyl benzene sulfonate, urea, acetic acid, and humic acid. It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.

This test method is applicable only to carbonaceous matter in the sample that can be introduced into the reaction zone. The syringe needle or injector opening size generally limits the maximum size of particles that can be so introduced.

In addition to laboratory analyses, this test method may be applied to stream monitoring.