1.1 This test method covers the determination of total nitrogen (TN) and total dissolved nitrogen (TDN) in surface water, seawater, groundwater, wastewater, and wastewater effluents in the range from 0.2500 mg/L N when used in conjunction with automatic dilution or automatic injection of less sample volume. The EPA 40 CFR Part 136 Appendix B Method Detection Limit (MDL) is 0.05 mg/L N or value determined by ILS. Higher concentrations may be determined by sample dilution. Lower concentrations may be possible by injecting larger sample volumes. Follow the manufacturers instructions. 1.2 The 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 an exited NO2. As the excited NO2 returns to the ground state, it emits radiation, which is measured photoelectrically. 1.3 Total 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. 1.4 This test method quantitatively recovers nitrogen from a large range of organic and inorganic nitrogen compounds. This 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. 1.5 This 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. 1.6 In addition to laboratory analyses, this test method may be applied to on-line captured continuous stream or process monitoring. 1.7 This test method is performance based. You may make modifications that improve the methods performance but do not change the oxidation or detection technique. 1.8 Units--The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
There is an increased interest by the U.S. EPA, 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 U.S. EPA definition of total nitrogen is TKN plus nitrate/nitrite. This test method measures total nitrogen as a single number using high-temperature oxidation followed by chemiluminescence detection.
Keywordsnitrogen; organic nitrogen; high-temperature catalytic oxidation; dissolved nitrogen; total nitrogen; particulate nitrogen
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top