Isotope ratio analysis of nitrate using Orbitrap Exploris Isotope Solutions

Nitrate (NO₃⁻) is a key component of the global cycling of nitrogen in natural and human-impacted environments. Analysis and interpretation of nitrate isotopes can reveal microbial pathways of nitrification and denitrification, as well as sources and fate of natural and anthropogenic nitrogen inputs to the environment. Isotope ratio analyses are investigating the relative abundances of the three heavier isotopes in nitrate (¹⁵N, ¹⁸O, and ¹⁷O) in comparison to the more abundant, lower mass isotopes (¹⁴N and ¹⁶O).

In this technical note, Thermo Fisher Scientific demonstrates how Thermo Scientific™ Orbitrap Exploris™ Isotope Solutions allow for comprehensive isotope analysis of nitrogen and oxygen within intact molecular nitrate ions. This includes non-mass-dependent oxygen isotope relationships and doubly substituted isotopologue abundances (i.e., clumped isotope effects).