1.1This test method covers the determination of total nitrogen (TN), and Total Dissolved Nitrogen (TDN) in water, wastewater, and seawater in the range from 0.05 4000 mg/L N when used in conjunction with automatic dilution. The EPA 40 CFR Part 136 Appendix B Method Detection Limit (MDL) is 0.01 mg/L N. Higher concentrations may be determined by manual sample dilution. 1.2The sample is injected onto a platinum catalyst heated at 720C. The sample converts into a gaseous phase and forced through a layer of catalyst ensuring conversion of all nitrogen containing compounds to nitrogen oxide NO. Reaction with ozone converts the NO to NO2. A chemiluminescence detector measures the resulting NO2. 1.3Total and dissolved organic carbon analysis by ASTM D7573 can be analyzed at the same time on the same sample simultaneously using a properly equipped analyzer. 1.4This test method quantitatively recovers nitrogen from a large range of organic and inorganic nitrogen compounds. The test method does not measure nitrogen gas (N2). It is the users responsibility to ensure the validity of this test method for waters of untested matrices. 1.5This test method is applicable only to nitrogenous 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. Optional automatic sample homogenization may be used. 1.6In addition to laboratory analyses, this test method may be applied to stream monitoring. 1.7The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
There is an increased interest by the USEPA, international regulatory agencies, and states in the analysis of total nitrogen. The current EPA regulations do not have a method that measures total nitrogen as a single result; the USEPA definition of Total Nitrogen is TKN plus nitrate/nitrite. This standard test method measures total nitrogen as a single number using high temperature oxidation followed by chemiluminescence detection.
Keywordshigh temperature catalytic oxidation; dissolved nitrogen; TKN; particulate nitrogen
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top