Quantitative determination of nitrogen by LA-ICP-MS using N-15 enriched binary calcium nitrides

The quantification capabilities for nitrogen with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were studied. The investigations were carried out on binary calcium nitrides (Ca2N, alpha-Ca3N2, beta-Ca3N2) prepared either with N-14 or N-15. Whereas the detection of N-14 is completely hampered by interference with nitrogen originating from air, a distinct signal of N-15 is detectable. Based on this knowledge the ablation parameters were optimized with respect to the signal intensity of N-15. Subsequently, N-15 was determined by use of three different quantification strategies which are presented in detail. So far, the precision and accuracy is about +/- 5%. Limits of detection of N-15 were determined as 5 mg g(-1).