Simplified Procedure for Optical Emission Analysis of Nitrogen 15 and Carbon 13

Abstract

In an endeavor to facilitate the use of stable isotopes in biological tracer research, we have developed a simple, real time procedure for reasonably accurate optical emission analysis of 15N and 13C in ammonium salts and bicarbonates, respectively. The amount of sample required for each analysis is in the range 10 to 100 μmol. In the procedure proposed, complicated chemical techniques have been avoided through (1) decomposition of the sample by heating; (2) removal of unwanted compounds, and regulation of pressure, by cooling; and (3) production of N2 and CO+ from NH3 and CO2, respectively, by electrodeless microwave interaction. These three steps are followed by (4) measurement of relevant peak heights in the N2 and CO+ spectra obtained.