| Abstract: | Abstract An 15N isotope analyser has been assembled for the quantitative determination of the percentage abundance of 15N isotope in nitrogen gas employing molecular optical emission spectroscopic technique. The (2,0) band of the second positive system of N2 was excited in a high frequency discharge. The band heads of the isotopic species 14N14N and 14N15N molecules were resolved using a 0.5 m monochromator and their intensity peaks were measured. The ratio of the peak heights enabled the quantitative determination of 15N in the N2 sample. The performance of the isotope analyser assembled was evaluated and it was found to be quite good as inferred from the analysis of primary standards. The analytical error in the 15N concentration-range 0.36 to 24% is <6% and rsd is <4%. A salient feature of the method adopted is that it is direct and does not call for the use of comparision standards. |
