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15 N NMR is the most effective method for investigation of structure of heterocycles with a high content of nitrogen atoms (tetrazoles, triazines and their annelated analogs). [7] [8] 15 N labeling followed by analysis of 13 C– 15 N and 1 H– 15 N couplings may be used for establishing structures and chemical transformations of nitrogen ...
Two sources of nitrogen-15 are the positron emission of oxygen-15 [8] and the beta decay of carbon-15. Nitrogen-15 presents one of the lowest thermal neutron capture cross sections of all isotopes. [9] Nitrogen-15 is frequently used in NMR (Nitrogen-15 NMR spectroscopy). Unlike the more abundant nitrogen-14, which has an integer nuclear spin ...
The abundance of 15 N is greater in human waste water than in natural water sources. Hence δ 15 N in benthic sediment gives an indication of the contribution of human waste to the total nitrogen in the sediment. Sediment cores analyzed for δ 15 N yield an historical record of such waste, with older samples at greater depths.
Nitrogen-15 (15 N) tracing is a technique to study the nitrogen cycle using the heavier, stable nitrogen isotope 15 N.Despite the different weights, 15 N is involved in the same chemical reactions as the more abundant 14 N and is therefore used to trace and quantify conversions of one nitrogen compound to another.
Nitrogen-15 is extensively used to trace mineral nitrogen compounds (particularly fertilizers) in the environment. [15] When combined with the use of other isotopic labels, 15 N is also a very important tracer for describing the fate of nitrogenous organic pollutants. [16] [17] Nitrogen-15 tracing is an important method used in biogeochemistry.
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Nitrogen oxides < 0.25 < 0.15 ... petrol engines varies from ≈15 ppm for well tuned engine with fuel injection and a catalytic converter up to 100,000 ppm ...
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