Abstract
A procedure for isotope‐ratio analysis of soil nitrogen is described which eliminates the ammonium distillation stage of the customary procedure. The nitrogen in the soil sample is converted to ammonium by Kjeldahl digestion without use of a catalyst, digestion being accomplished by heating the sample with sulfuric acid containing a high concentration of potassium sulfate (ca. 0.7g/ml of H2SO4). An aliquot of the digest is partially neutralized and treated in vacuo with alkaline hypobromiteiodide solution, and the N2 liberated by this treatment is analyzed by the mass spectrometer. This simplified procedure eliminates problems encountered in distillation and concentration of ammonium samples for N15 analysis and gives the same results as the customary procedure.
Funding Information
  • Tennessee Valley Authority

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