Dear Arndt,
we produced a similar set of substances, including additionally heterocycles

with O, N and S. They are calibrated against NBS22 using TC/EA by W. Brand
and some of them are calibrated against V-SMOW using off-line combustion and
reduction of water over Mn by A. Rossmann.
All other groups working on this topic will have their on standards. Maybe
we should try to organize some kind of ring test to compare the results of
different labs.
gerd

Arndt Schimmelmann wrote:

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> Hydrogen and carbon stable isotope standards for organic
> compound-specific investigations
>
> Compound-specific hydrogen isotope ratios for organic hydrogen are now
> analytically accessible by a combination of GC, high-temperature
> pyrolysis to elemental hydrogen, and subsequent on-line irm-MS (Sessions
> et al., 1999, Org. Geochem. 30: 1193-1200; Scrimgeour et al., 1999,
> Rapid Comm. Mass Spec. 13: 271-274; Hilkert et al., 1999, Rapid Comm.
> Mass Spec. 13: 1226-1230; Tobias and Brenna, 1997, Anal. Chem. 69:
> 3148-3152).  Complete irmGCMS-systems with interfaces are commercially
> available, but there has been no isotopically defined set of organic
> compounds for routine calibration and D/H quality control.  Standards
> that reliably establish or confirm isotopic calibrations must be in the
> same form as the unknown analytes.  In contrast, the use of intermittent
> spikes of introduced elemental “standard” hydrogen gas is fraught with
> potential problems because it does not take into account D/H
> fractionations that may occur in the analytical train between injection
> in the GC and the exit of the pyrolysis reactor.
>
> The Biogeochemical Laboratories at Indiana University, in collaboration
> with Woods Hole Oceanographic Institution (A. Sessions, J.M. Hayes),
> first established the purity of n-alkanes (range from C-12 to C-50) and
> n-alkanoic acid methyl esters (C-10, C-20, C-30 FAMEs) by GC-MS,
> followed by the measurement of D/H and 12C/13C ratios for each compound.
> Up to five replicate analyses for each compound were performed off-line,
> via conventional combustion of milligram-amounts of individual compounds
> in quartz ampules and cryogenic purification of combustion gases in a
> vacuum line.  Water was converted to elemental hydrogen in contact with
> uranium, followed by collection of hydrogen gas using a Toepler pump.
> Gas yields and elemental H/C ratios were routinely monitored
> manometrically for quality control.  Hydrogen and carbon isotopic ratios
> were determined using MAT252 mass-spectrometers at Indiana University.
> The hydrogen isotopic calibration employed the conventional
> normalization to VSMOW (zero per mil) and SLAP (-428 per mil).
>
> We currently have 3 types of standards available for the research
> community:
>
> 1.  Mixture “A” of fifteen n-alkanes (C-16 to C-30) containing ca. 100
> nmol H2 per compound per microliter of solution. This is equivalent to
> approximately 1200 ng alkane per microliter of solution. This solution
> is ideal for establishing the precision and accuracy of an irmGCMS
> instrument.
>
> 2.  Mixture “B” of fifteen n-alkanes (C-16 to C-30) containing a 5-fold
> range of concentrations (arranged in three pentads with rising
> concentrations; see Table below), from 20 nmol H2 to 100 nmol H2 per
> compound per microliter of solution. This mixture is designed
> specifically to test the accuracy of H3+ correction in
> hydrogen-isotope-IRMS (see Sessions et al., 1999). In addition, the
> solution can be used to measure the H3+ factor under conditions closely
> matching those experienced by analytes. This mixture continues to be
> invaluable in the laboratory at WHOI and is used every day.
>
> 3.  Individual n-alkanes (C-12 to C-50) and individual fatty acid methyl
> esters (C-10, C-20, C-30). While peaks of “standard” H2 gas can be used
> to calibrate the delta values of unknown compounds, a more robust
> approach is to use co-injected compounds as the isotopic standards. We
> therefore offer individual solutions of any or all of these compounds,
> each containing ca.100 nmol H2 per microliter of solution.  Custom
> mixtures are available upon request.
>
> As a public university, we will supply this reference standard material
> as a service to the scientific community rather than as a commercial
> product. Trial amounts sufficient for multiple injections are available
> free of charge (international shipping charges may apply).  To offset
> our significant investment in analytical effort, we will ask for
> compensation for each 0.5 mL aliquot of standard mixtures sealed under
> argon in brown glass ampules, which will reflect a cost of a few cents
> per injection after appropriate dilution of our product to match the
> sensitivity of modern irmGCMS systems.  Additional information, isotope
> ratios, and a chromatogram with traces of masses 2 and 3 for mixture “B”
> are available in the 'service' section of the following home page:
> http://www.indiana.edu/~geosci/people/faculty/schimmelmann.html.
> Our standards will be accompanied with documentation covering purity,
> isotopic ratios, and concentrations.  Although intended primarily for
> D/H research, our standards are equally useful for irmGCMS work on
> carbon isotope ratios.  Our isotope standards are research materials
> offered for use without guarantees and without acceptance of any
> responsibilities for damages arising from its use or possible failure in
> any application. It is not sold for profit and is distributed as a
> service to those engaged in geochemical research.
> --
> Arndt Schimmelmann, Ph.D.
> Biogeochemical Laboratories
> Department of Geological Sciences
> Geology 129, Indiana University
> 1005 East 10th Street
> Bloomington, IN 47405-1405
> Ph   (812) 855-7645
> home (812) 339-3708
> FAX  (812) 855-7961
> e-mail  [log in to unmask]