Abstract
A simple and rapid method was developed for the δ15N determination of ammonium and nitrate in water samples. This method is based on an on-line isotope analysis using an elemental analyzer coupled to a mass spectrometer. The ammonium and nitrate in sample solutions are separated as ammonium into diluted H2SO4 from each other by sequential distillation techniques. Then, the ammonium in the distillate is precipitated directly as an insoluble salt of (C6H5)4BNH4, which is subsequently combusted in an elemental analyzer for δ15N determination. This precipitation step allows us to eliminate the evaporation step used for sample preparation in the previous on-line methods, which contributes to simple and rapid determination. The δ15N values of precipitates did not depend on the fraction (F) of NH4+ precipitated in the investigated range of F = 0.64–0.96, showing insignificant isotope fractionation during precipitation. Analyses of the solutions prepared from Reference Materials, (NH4)2SO4 and KNO3 distributed by the National Institute of Standards and Technology (NIST) and also the rain samples showed that this method can produce good quality isotope measurements.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
