Sample Preparation and 15-N Analysis Using a Statron Noi-5 Optical Analyzer

Procedures for sample preparation and 15-N analysis using a Statron NOI-5 Optical Analyzer are outlined and compared with those previously reported. Procedures are based on N2 generation by oxidation of NH3 using NaOBr, careful regulation of N2 and Ar partial pressures in an electrodeless discharge tube, excitation by a R.F. generator and measurement of the relative intensities of the light emitted by the excited N2 molecules of differing mass. The approach outlined offers a relatively inexpensive, routine procedure for 15-N analysis with a precision and accuracy in the range of 1 to 3 percent. The relatively large quantity of N and length of time required for sample preparation are currently the two greatest limitations. Both of these limitations can probably be further minimized.