Isotope Analytical Methods

Parameter When Method Reference Instrument Analytical Prec (2sigma) Standards

delta18O (water) Pre1996 Equilibration with CO2 + IRMS Craig (1957) VG602C 0.11 0.08 SMOW, VSMOW, SLAP *
  Post1996 As above, automated   Finnigan Delta S    

deltaD Pre1998 Zn reduction + IRMS Coleman et al. (1982) VG602 1.5-2.0‰ SMOW, VSMOW, SLAP *
  Post1998 Cr reduction, automated +IRMS Gehre et al. (1996) Finnigan Delta S 0.9‰  

delta34S Pre2001 Cu2O reduction + IRMS Coleman and Moore (1978) VG602C Thermo 0.13‰ OGS 1,
NBS 127
  Post2001 Combustion in O2 + CFIRMS   Finnigan Delta Plus + Costech Element Analyzer 0.13‰  

3H   Electrolytic enrichment + liquid scintillation counting Theodórsson (1996) Quantulus
DL = 0.6
to 0.9 TU
NIST SRM 4361 B, C

14C   Liquid scintillation counting on benzene Polach et al. (1973) Quantulus
DL = 1-2
Oxalic Acid I
    AMS     DL = 0.2 pMC Oxalic Acid I, II

18O (sulfate)   Reduction to CO + CFIRMS   Thermo Finnigan Delta Plus + TCEA 0.3% OGS 1


  • IRMS = Isotope ratio mass spectrometry
  • CFIRMS = Continuous flow isotope ratio mass spectrometry
  • DL = detection limit
  • * see Coplen et al, 1995


Coleman, M. L. and Moore, M.P. Direct reduction of sulfates to sulfur dioxide for isotopic analysis. Anal. Chem. 1978, 50,1594-1598.

Coleman, M.L., Shepherd, T.J., Durham, J.J., Rouse, J.E., and Moore, G.R., 1982, Reduction of water with zinc for hydrogen isotope analysis. Anal. Chem. 54, 993-995.

Coplen, T.B., 1995, Reporting of stable carbon, hydrogen and oxygen abundances. Vienna, International Atomic Energy Agency, IAEA Tecdoc 825: 31-34.

Craig, H., 1957, Isotopic standards for carbon and oxygen and correction factors for mass spectrometric analysis of carbon dioxide. Geochim. Cosmochim. Acta., 12: 133-149

Gehre, M., Hoefling, R., Kowski, P. and Strauch, G., 1996, Sample preparation device for quantitative hydrogen isotope analysis using chromium metal. Anal. Chem. 68, 4414-4417.

Polach, H., Gower, J., and Fraser, I., 1973 Synthesis of high-purity benzene for radiocarbon dating. In Rafter, T.A. and Grant-Taylor, T., eds., Proceedings of the 8th International 14C Conference. Vol 1. Wellington, Roy. Soc. New Zealand, B36-B49.

Theodórsson, P., 1996, Measurement of weak radioactivity. Singapore, World Scientific, 333 pp.