DISTILLATION SOLUTION WITH AND WITHOUT INDICATOR FOR N-15 MEASUREMENTBY OPTICAL-EMISSION SPECTROMETRY

Optical emission spectroscopy provides a rapid and precise method for determining N-15/N-14 ratios of N-15-enriched plant and/or soil sample s. The objective of this study was to determine the effect of an indic ator added in the distillation solution on the success rate of tube li ghting in the optical emission spectrometer over a large range of N co ncentration in N-15 enriched plant samples. One-hundred-eighty plant s amples with large ranges of N concentration (4 to 30 g . kg(-1) dry we ight) and N-15 atom enrichment (0.368 to 1.635%) were analyzed. Our da ta suggest that there was no difference in the success rate of tube li ghting in emission spectroscopy and in N-15/N-14 ratio measured betwee n samples prepared with and without addition of indicator in the disti llation solution.