Carbon Isotopic Reference
δ13C Values of Carbon Isotopic Reference Materials
Description |
NIST RM # |
Material |
Nominal Unit Size |
δ13CVPDB |
Footnote |
Ref |
NBS 19 |
8544 |
limestone |
0.4 g |
+1.95 ‰ |
* |
16 |
L-SVEC |
8545 |
lithium carbonate |
0.4 g |
–46.6 ‰ |
* |
5 |
NBS 18 |
8543 |
carbonatite |
0.4 g |
–5.01 ‰ |
|
5 |
NBS 22 |
8539 |
oil |
1 mL |
–30.03 ‰ |
|
5 |
NGS1 |
8559 |
natural gas (coal origin) |
< 2 g |
–29.0 ‰ (CH4) |
|
3 |
NGS2 |
8560 |
natural gas (petroleum origin) |
< 2 g |
–44.5 ‰ (CH4) |
|
3 |
NGS3 |
8561 |
natural gas (biogenic) |
< 2 g |
–72.8 ‰ (CH4) |
|
3 |
CO2-Heavy Paleomarine Origin |
8562 |
CO2 |
2 tubes |
–3.72 ‰ |
|
5 |
CO2-Light, Petrochemical Origin |
8563 |
CO2 |
2 tubes |
–41.59 ‰ |
|
5 |
CO2-Biogenic, Modern Biomass Origin |
8564 |
CO2 |
2 tubes |
–10.45 ‰ |
|
5 |
USGS24 |
8541 |
graphite |
0.8 g |
–16.05 ‰ |
|
5 |
USGS40 |
8573 |
L-glutamic acid |
1 g |
–26.39 ‰ |
|
5 |
USGS41 |
8574 |
L-glutamic acid |
0.5 g |
+37.63 ‰ |
|
5 |
IAEA-CO-1 |
|
calcium carbonate |
0.5 g |
+2.49 ‰ |
|
5 |
IAEA-CH-3 |
|
cellulose |
0.5 g |
–24.72 ‰ |
|
5 |
IAEA-CH-6 |
8542 |
sucrose |
1 g |
–10.45 ‰ |
|
5 |
IAEA-CH-7 |
8540 |
polyethylene foil |
3.6 g |
–32.15 ‰ |
|
5 |
IAEA-CO-8 |
|
calcium carbonate |
0.5 g |
–5.76 ‰ |
|
5 |
IAEA-CO-9 |
|
barium carbonate |
1 g |
–47.32 ‰ |
|
5 |
IAEA-600 |
|
caffeine |
0.5 g |
–27.77 ‰ |
|
5 |
IAEA-601 |
|
benzoic acid |
0.5 g |
–28.81 ‰ |
|
5 |
IAEA-602 |
|
benzoic acid |
0.5 g |
–28.85 ‰ |
|
5 |
* Exact values defining the delta scale
Recommendation on the Reporting of δ13C Measurements
At the Beijing General Assembly in 2005, the Commission recommended that δ13C values of all carbon-bearing materials be measured and expressed relative to VPDB on a scale normalized by assigning consensus values of –46.6 ‰ to L-SVEC lithium carbonate and +1.95 ‰ to NBS 19 calcium carbonate, and authors should clearly state so in their reports.
Authors are encouraged to report their measurement results for δ13C values of NBS 22 oil, USGS 41 L-glutamic acid, IAEA-CH-6 sucrose, or other internationally distributed reference materials, as appropriate for the measurement method concerned, had they been analyzed with the author’s samples.
This recommendation supersedes the recommendation made by the Commission in 1993 (ref. 22). Full analytical data supporting this recommendation is found in reference 5.
Authors should discontinue reporting their δ13C values relative to PDB.
The full recommendation appears in:
Atomic weights of the elements 2005, Wieser, M. E., Pure Appl. Chem., 78, 2051-2066 (2006). [full text - pdf 217 KB] {TSAW 2005.pdf}
References
3. Hut, G., Consultants' group meeting on stable isotope reference samples for geochemical and hydrological investigations, Vienna, International Atomic Energy Agency, 42 p (1987).
5. Coplen, T.B., Brand, W.A., Gehre, M., Gröning, M., Meijer, H. A. J., Toman, B, and Verkouteren, R. M., New guidelines for δ13C measurements, Anal. Chem., 78, 2439-2441 (2006).
16. Gonfiantini, R., 1984, Advisory group meeting on stable isotope reference samples for geochemical and hydrological investigations, IAEA, Vienna, 19-21 September 1983, Report to the Director General, International Atomic Energy Agency, 77 p.
22. Coplen, T. B., Reporting of stable hydrogen, carbon, and oxygen isotopic abundances, Pure Appl. Chem., 66, 273-276 (1994).
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