title: [Modification of a method of determining 15N in biological material].
abstract: A method is described for preparation of nitrogen samples and estimation of 15N concentration in free amino acids and urea, isolated from heart muscle, using mass-spectometric analysis. Components of the tissue extracts were separated at the preparative scale; amino acids and urea were desalted by means of ion exchange chromatography. CHN-analyzer was used to measure content of nitrogen in urea and amino acids. The method required about 100 micrograms of nitrogen for the isotope analysis.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D005609:Free Radicals; D008722:Methods; D009206:Myocardium / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D009587:Nitrogen Isotopes; D051381:Rats; D014508:Urea / Q000032:analysis
chemical_list: D000596:Amino Acids; D005609:Free Radicals; D009587:Nitrogen Isotopes; D014508:Urea; D009584:Nitrogen
vernacular_title: Modifikatsiia metoda opredeleniia 15N v biologicheskom materiale.