Picture of NBS 22
Picture of NBS 22
Picture of NBS 22

NBS 22

Product tags
€200.00
Producing Laboratory: TERC
Availability: In stock
Oil

NBS 22 is a secondary reference material. Its intended use is as calibrant when δ(13C) and δ(2H) are determined in organic materials using IRMS (Isotope Ratio Mass Spectrometry) coupled with an EA (Elemental Analyser) and Pyrolizer, for obtaining traceability of the data to the VPDB-LSVEC δ(13C) scale and VSMOW-SLAP δ(2H) scale, respectively. NBS 22 was prepared by S. Silverman, Chevron Oil Company, La Habra, California [1]. Details about the characterization of NBS 22 are reported in [2] and [3]. 

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Stable isotope ratio

Reference value

Combined standard uncertainty with k=1
δ(13C)VPDB-LSVEC  (‰)-30.030.04
δ(2H)VSMOW-​SLAP (‰)-117.20.6

Note: For δ(13C), currently two scales exist and are in use: VPDB and VPDB-LSVEC.  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 [https://doi.org/10.1002/rcm.10018)]. 

End users should state the values of reference materials used to normalize isotope data following the minimum requirements established by IUPAC [https://doi.org/10.1515/pac-2021-1108] and in the case of carbon, 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. ​SILVERMAN, S.R., "Investigations of petroleum origin and evolution mechanisms by carbon isotope studies", Isotopic and Cosmic Chemistry (CRAIG, H., MILLER, S.L., WASSERBURG, G.J., Eds.), North Holland, (1964) 92-102.
  2. COPLEN, T.B., BRAND, W.A., GEHRE, M., GRÖNING M., MEIJER, H.A.J., TOMAN, B., VERKOUTEREN, R.M., New Guidelines for 13C Measurements, Anal. Chem. 78 7 (2006) 2439-2441.
  3. SCHIMMELMANN, A., QI H., COPLEN, T.B., BRANDT, W.A., FONG, J., MEIER-AUGENSTEIN, W., KEMP, H.F., TOMAN, B., ACKERMANN, A., ASSONOV, S., AERTS-BIJMA, A.T., BREICHA, R., CHIKARAISHI, Y., DARWISH, T., ELSNER, M., GEHRE, M., GEILMANN, H., GROENING, M., HELIE, J.F., HERRERO-MARTIN, S., MEIJER, H.A.J., SAUER, P.E., SESSION A.L., WERNEN R.A. Organic Reference Materials for Hydrogen, Carbon, and Nitrogen Stable Isotope-Ratio Measurements: Caffeines, n‑Alkanes, Fatty Acid Methyl Esters, Glycines, L‑Valines, Polyethylenes, and Oils. Anal. Chem. 88 (2016) 4294−4302    
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