USGS34 was produced by J.K. Böhlke, S.J. Mroczkowski and T.B. Coplen, U.S. Geological Survey, Reston, USA, . It was prepared from equilibrating nitric acid with δ18O depleted water and subsequent neutralisation with KOH.
(R/I/C) Classification assigned to the property value for analyte (Recommended/Information/Certified)
BÖHLKE, J.K., MROCZKOWSKI, S.J., COPLEN, T.B., Oxygen isotopes in nitrate: new reference materials for 18O:17O:16O measurements and observations on nitrate water equilibration. Rapid Comm. Mass Spectrom. 17 (2003) 1835-1846.