Since the 1980s, our team has put strong effort in the development of nitrogen isotope analysis (ratio 15N/14N) on very small samples, down to 1000 times lower than usual conditions. We have been able to routinely measure isotope composition of only few nanomoles of nitrogen, included in different types of matrix (diamonds, anthracite, graphite, organic matter, silicates...) with a precision better than ±0.5 ‰ (2 SD).
The analysis of very small samples is performed on our static mass spectrometer after online gas extraction. Another vacuum line is available and allows the preparation of sealed tubes for N analysis in various sample types. The sample size is typically of few mg (diamonds, graphite, anthracite) to few tens of mg (silicates).
The isotope composition of samples enriched in nitrogen, such as organic matter-rich sediments, is routinely measured via elemental analyzer (few mg of samples) and/or other extraction lines specifically designed for N-rich samples (> 1 μmol of nitrogen) and mass spectrometry (Delta Plus XP). The external reproducibility of samples and standards typically around ± 0.3 ‰ (2 SD).
For further information, please contact Magali Ader, Vincent Busigny or Pierre Cartigny.