IAEA-CH-3

• Unit Size: 0.5 g
• Price per Unit: 200 EUR
• Report:  
• Date of Release: 2/1/2004
• Reference Sheet: download (pdf)
• Contact point: Analytical-Reference-Materials.Contact-Point@iaea.org

IAEA-CH-3 is aimed at δ¹³C calibrations by TC/EA techniques.

IAEA-CH-3 was prepared in 1989 at the IAEA from large batch of cellulose harvested from approximately 40 years old trees originating from Sweden. Processed material was pressed into sheets and initially characterized for ¹⁴C value of IAEA-C3. Three kilograms of these sheets were milled to fine powder, homogenized and characterised for δ¹³C value of IAEA-CH-3. The final calibration of the material was performed in 2004 by a small group of experienced laboratories together with the re-calibration of most of the other organic carbon stable isotope reference materials available at IAEA [1].

(R/I/C) Classification assigned to the property value for analyte (Recommended/Information/Certified)

For δ(¹³C), currently two scales exist and are in use: VPDB (Vienna Peedee belemnite) and VPDB-LSVEC (lithium carbonate prepared by H.J. Svec), as acknowledged by experts during the 12th IAEA meeting held in Vienna, 22-26 January 2024 (Camin et al., 2025, RCM, Rapid Communications in Mass Spectrometry, 2025; 39:e10018 1 of 11 https://doi.org/10.1002/rcm.10018). δ(¹³C) values reported on the VPDB and VPDB-LSVEC scale can differ, with maximum reported differences (VPDB minus VPDB-LSVEC) of +0.3 ‰ for materials with carbon isotope delta values around –45 ‰ and negligible difference (below current analytical combined uncertainty) at carbon isotope delta values close to zero.

End users should state the values of reference materials used to normalize isotope data following the minimum requirements established by IUPAC[2] and whether they are publishing δ(¹³C) values on the VPDB scale or the VPDB-LSVEC scale. Users should ensure that in one calibration they only use values for reference materials assigned on one scale.

References:

1. COPLEN, T.B., BRAND, W.A., GEHRE, M., GRÖNING, M., MEIJER, H.A.J., TOMAN, B., VERKOUTEREN, R.M., New guidelines for δ¹³C measurements. Anal. Chem. 78 (2006) 2439-2441.
2. SKRZYPEK, G. et al., Minimum requirements for publishing hydrogen, carbon, nitrogen, oxygen and sulfur stable-isotope delta results (IUPAC Technical Report), Pure Appl. Chem. (2022) 1.