Influence of δ18 O of water on measurements of δ18 O of nitrite and nitrate.
Kanae KobayashiKeitaro FukushimaYuji OnishiKazuya NishinaAkiko MakabeMidori YanoScott D WankelKeisuke KobaSatoshi OkabePublished in: Rapid communications in mass spectrometry : RCM (2020)
Oxygen isotope ratio measurements of NO2 - by the azide method are highly sensitive to δ18 OH2O as a result of significant oxygen isotope exchange between NO2 - and H2 O. Therefore, to obtain the most accurate measurements water with the same δ18 OH2O value as that of the sample must be used to make the NO2 - and NO3 - standards.