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    Carbon Isotope Materials

    The n(13C)/n(12C) ratio probably is the most frequently analyzed stable isotope quantity. A variability in carbon isotopic compositions of about 180 ‰ is observed in naturally occurring terrestrial materials.

    δ13C Values of Reference Materials

    Name NIST RM Material δ13CVPDB
    PDBcalcite 0 ‰ (discontinued)
    NBS 198544limestone+1.95 ‰ *
    LSVEC8545Li2CO3-46.6 ‰ *
    NBS 188543carbonatite-5.01(3) ‰
    NBS 20Solnhofen limestone-1.06(2) ‰
    NBS 228539oil-30.03(5) ‰
    CO2-heavy8562CO2-3.72(3) ‰
    CO2-light8563CO2-41.59(6) ‰
    CO2-biogenic8564CO2-10.45(3) ‰
    NARCIS IICO2+1.923(3) ‰
    NARCIS ICO2-8.55(2) ‰
    USGS248541graphite-16.05(4) ‰
    USGS408573L-glutamic acid-26.39(4) ‰
    USGS418574L-glutamic acid+37.63(5) ‰
    IAEA-CO-18574CaCO3+2.48(3) ‰
    USGS42human hair (Tibetan)-21.09(10) ‰
    USGS43human hair (Indian)-21.28(10) ‰
    IAEA-CH-3cellulose-24.72(4) ‰
    IAEA-CH-68542sucrose-10.45(3) ‰
    IAEA-CH-78540polyethylene-32.15(5) ‰
    IAEA-CO-8carbonatite-5.76(3) ‰
    IAEA-CO-9BaCO3-47.32(5) ‰
    IAEA-600caffeine-27.77(4) ‰
    IAEA-601benzoic acid-28.81(4) ‰
    IAEA-602benzoic acid-28.85(4) ‰
    IAEA-303ANaHCO3[+91, +96] ‰
    IAEA-303BNaHCO3[+460, +472] ‰
    IAEA-309AUL-D-glucose+93.9(1.0) ‰
    IAEA-309BUL-D-glucose+535.3(5.0) ‰
    IRMM-BCR 656ethanol (wine origin)-26.91(7) ‰
    IRMM-BCR 657glucose-10.76(4) ‰
    IRMM-BCR 660ethanol (wine origin)-26.72(9) ‰
    Name NIST RM Material δ13CVPDB

    Footnotes      Back to Top
    * Exact values defining the δ13CVPDB-LSVEC scale.
    ** See the Assessment of international reference materials for isotope-ratio analysis for more details.
    Values in parenthesis are expanded (k = 2) uncertainties applicable to the last digits. The values listed in this table are compilation and are not necessarily CIAAW recommendations.


    W.A. Brand et al
    Assessment of international reference materials for isotope-ratio analysis Pure and Applied Chemistry 86, 425-467 (2014)

    At the Beijing IUPAC General Assembly in 2005, CIAAW recommended that δ13C values of all carbon-bearing materials be measured and expressed relative to the VPDB on a scale normalized by assigning consensus values of –46.6 ‰ to LSVEC lithium carbonate and +1.95 ‰ to NBS 19 calcium carbonate, and authors should clearly state so in their reports. The full recommendation appears in Atomic weights of the elements 2005 by M.E. Wieser, Pure Appl. Chem. 78 2051-2066 (2006).