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Dear Brett!

You are welcome. If you have any questions don't hesitate to contact me 
off-list.

Cheers, Wolfgang


On 12/12/2018 18:55, Hill, Brett (AAFC/AAC) wrote:
>
> Thank you Wolfgang.  This information will be helpful.
>
> Brett
>
> *From:*Stable Isotope Geochemistry <[log in to unmask]> *On 
> Behalf Of *Wolfgang Wanek
> *Sent:* Wednesday, December 12, 2018 1:03 AM
> *To:* [log in to unmask]
> *Subject:* Re: [ISOGEOCHEM] 15N of microbial biomass sample extractions
>
> Dear Brett,
>
> CFE coupled to K2SO4 extraction (best at lower concentrations such as 
> 50 mM) and EA-IRMS is a standard protocol though not very sensitive.
> If you want to become more sensitive and get rid of the salt load, and 
> if you have access to a purge-and-trap IRMS (e.g. Gasbench II with 
> liquid N2 trap coupled to IRMS)
> you can alternatively use alkaline persulfate oxidation of the 
> extracts to nitrate and then convert nitrate to N2O chemically (see 
> attached paper) or using the denitrifier method.
>
> Kind regards,
>
> Wolfgang
>
> On 12/11/2018 11:26 PM, Hill, Brett (AAFC/AAC) wrote:
>
>     Hello all,
>
>     I have recently been sent dried K2SO4 salts from soil microbial
>     biomass sample extractions.  I am getting too little response for
>     nitrogen in particular to get robust results.  It will be a while
>     before I am able to communicate with the preparer of these samples
>     to determine the particulars of their method.  In the meantime, I
>     would like to be more educated on what may have worked for others
>     in terms of extraction ratios, salt weights, etc.  Does anyone
>     have experience with CFE that can give pointers or cautions that
>     might help increase the amount of nitrogen in the samples?
>
>     Thanks
>
>     Brett
>
>     Brett Hill
>
>     Stable Isotope Lab
>
>     Agriculture and Agrifood Canada
>
>     Lethbridge Research and Development Centre
>
>     5403 1^st Av. S.
>
>     Lethbridge, AB.
>
>     T1J 4B1
>
>     403-317-3455
>
> -- 
> Assoc. Prof. Dr. Wolfgang Wanek
> Division of Terrestrial Ecosystem Research
> Department of Microbiology and Ecosystem Science
> Research Network "Chemistry Meets Microbiology"
> University of Vienna
> A-1090 Vienna, Althanstrasse 14
> Phone: +43 1 4277 76662
> Fax: +43 1 4277 9542
> Email:[log in to unmask] <mailto:[log in to unmask]>

-- 
Assoc. Prof. Dr. Wolfgang Wanek
Division of Terrestrial Ecosystem Research
Department of Microbiology and Ecosystem Science
Research Network "Chemistry Meets Microbiology"
University of Vienna
A-1090 Vienna, Althanstrasse 14
Phone: +43 1 4277 76662
Fax: +43 1 4277 9542
Email: [log in to unmask]