P. R. Srinivasan, R. Lichter
Nov 1, 1977
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Influential Citations
72
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Journal
Journal of Magnetic Resonance
Abstract
Abstract The 15N resonance positions of liquid ammonia, ammonium nitrate, ammonium chloride, nitromethane, and nitric acid, all of which have been proposed as nitrogen chemical shift references, have been measured under a variety of conditions. The chemical shifts of ammonium chloride and nitric acid vary with pH and concentration, while that of ammonium nitrate is independent of these factors. The resonance position of liquid ammonia is temperature dependent in an accountable manner. The earlier suggestion of nitromethane as an external primary measurement reference is supported, and a mixture of CH 315NO2 and CD314NO2 is proposed as a combination lock and reference. The use of ammonia as a possible substance for reporting nitrogen chemical shifts is discussed.