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Thanks everyone for the thoughtful replies. I learn so much important info
from this community on a daily basis.

While we are interested in having some H2 of known dD in house, we do not
plan to use it for standardization to VSMOW or any other scale. We
routinely use two point scale anchors based on standards provided by Arndt
et al. And then use this normalized scale to calibrate a third standard
from Arndt to see how close we are getting to accepted. We are generally
within a few permil, very close to 'within error'.

One question we've been asking ourselves though is how often we need to
perform a 2 point anchor... every sequence table (in other words, daily),
weekly, every new reactor (3-4 weeks)? If I run 2 anchor standards 3-5
times in every sequence, plus the other 'unknown' standard 3 times, that's
9-13 sequence lines. Then you've got to add in drift standards to make sure
the run as a whole stays 'level'. You run out of room for samples! My
goodness! So I'd be interested in hearing if there is an accepted protocol,
and if not, if folks would be willing to share their experience with
balancing the needs of quality assurance with those of the lab (data
production).

Thanks again, for any and all info.

Best,

On Thu, Oct 13, 2016 at 4:37 PM, Wolfram Meier-Augenstein (aps) <
[log in to unmask]> wrote:

> Even a lecture bottle of H2 with a “calibrated” value represents still
> only a single point of “reference” and does not do away with the need for
> proper scale calibration using two scale anchors spanning a d2H value range
> similar or identical to that covered by VSMOW/SLAP.  Anybody can verify
> this for themselves quite easily.  Use VSMOW(2) to dial in (aka “calibrate)
> the d2H value of your H2 cylinder. Once you are happy with the result, use
> the cylinder gas d2H value thus obtained to run SLAP or even GISP against
> it and see what the difference is between cylinder gas “calibrated” vs.
> accepted.
>
>
>
> Besides, it is impossible to correct for scale compression effects using
> merely 1 single point of scale reference. The need for a 2 point scale
> calibration, especially for 2H but also for other light element isotopes
> has covered extensively in the literature and in fact forms part of IUPAC
> guidelines for stable isotope ratio measurements and reporting results
> thereof.  Recommended reading on this subject includes Chapter 1
> (specifically pages 34 and 35), Chapter 40 and Chapter 41 in Pier de
> Groot’s Handbook of Stable Isotope Analytical Techniques (Vol. I); Figure
> 41.2 is reason alone to read Chapter 41.
>
>
>
> Another good and instructive read on this subject (using 34S analysis as
> example) is Appendix B of Zach Sharp’s book Stable Isotope Geochemistry.
>
>
>
> While of course a convenient way to generate measured (‘raw’) d2H values,
> as Arndt has already pointed out the use of a cylinder gas to “calibrate”
> H2 generated from sample conversion that on top has entered the ion source
> via a separate (different) gas train does not meet the identical treatment
> requirements.
>
>
>
> Using a dialled in H2 cylinder to generate measured d2H values has of
> course its advantages.  It helps writing SOPs with regard to acceptance /
> rejection criteria for measured d2H values of one to two QC materials on
> the basis of which one decides whether to continue with or abort a sample
> batch run sequence.
>
>
>
> Best,
>
>
>
> Wolfram
>
>
>
>
>
> *From:* Stable Isotope Geochemistry [mailto:[log in to unmask]] *On
> Behalf Of *Paul Eby
> *Sent:* 13 October 2016 20:57
> *To:* [log in to unmask]
> *Subject:* Re: [ISOGEOCHEM] Hydrogen Refgas of know value
>
>
>
> You can get this from Oztech (Chuck Douthitt). He has lecture bottles of
> pure H2, calibrated with a variety of isotopic values. Contact him by email
> at: [log in to unmask]
>
>
>
> Paul Eby
>
>
>
>
>
> Water Management
>
> Alberta Innovates - Technology Futures
> Vancouver Island Technology Park
> 3 - 4476 Markham St., Victoria, BC, Canada V8Z 7X8
>
> Phone: 250-483-3290 | Fax: 250-483-1989
> [log in to unmask]
> AlbertaTechFutures.ca
>
>
>
>
>
>
>
> *From:* Stable Isotope Geochemistry [mailto:[log in to unmask]
> <[log in to unmask]>] *On Behalf Of *Jeff Salacup
> *Sent:* October-13-16 11:36 AM
> *To:* [log in to unmask]
> *Subject:* [ISOGEOCHEM] Hydrogen Refgas of know value
>
>
>
> Greetings!
>
>
>
> Can one purchase a bottle of hydrogen gas with a know dD ratio? If so,
> where, and is it worth the cost?
>
>
>
> Best!!
>
>
>
>
>
>
> --
>
> Jeff
>
>
>
>
>
>
>
>
>
> *Two things are infinite: the universe and human stupidity; and I'm not
> sure about the universe. - Einstein*
>
>
>
>
>
> *__________________________________________________________________*
> *Jeff Salacup, Ph.D.*
>
> *Stable Isotope & Biogeochemistry Lab Manager*
>
> *UMass-Amherst*
>
>
>
>
>
>
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-- 
Jeff




*Two things are infinite: the universe and human stupidity; and I'm not
sure about the **universe. - Einstein*




*__________________________________________________________________**Jeff
Salacup, Ph.D.*
*Stable Isotope & Biogeochemistry Lab Manager*
*UMass-Amherst*