-----Mensaje original-----
De: Stable Isotope Geochemistry [mailto:[log in to unmask]] En nombre de Pier de Groot
Enviado el: Miércoles, 13 de Agosto de 2008 09:46 a.m.
Para: [log in to unmask]
Asunto: Re: [ISOGEOCHEM] sodium azide preservative

Dear Marinus,

After sending you my message (short while ago), I decided to give a phone
call to sort out what was wrong not getting any admission, and only error
messages as being a guest visitor of ScienceDirect.

This was a good idea, since the lady helping me gave me a good advice how to
handle (things seemd to hang on cookies, did not think about that
possibility myself stupid enough...). So problem is solved, also if it may
repeat itself in future. Thanks for the help anyway.

Best regards,
Pier.
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Delta Isotopes Consultancy

Dr. Pier A. de Groot
Pastoor Moorkensstraat 16
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Belgium
Tel. +32 (0)14 326 205
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Associate editor for stable isotopes of eEarth on-line magazine
http://www.electronic-earth.net

Head of Isotopes in Geosciences of the European Geoscience Union (EGU).
EGU Home web-site: http://www.copernicus.org/EGU/EGU.html

Scientific Committee member of BASIS (Benelux Association of Stable Isotope
Scientists).
http://www.basis-online.eu/

Visit my WEB-site about my ³Handbook of Stable Isotope Analytical
Techniques², with a link to the Elsevier web site on the handbook (marked:
ŒOrder Now¹):
http://users.pandora.be/handbook/index.html
last update: August 15, 2005
Volume I is available. Volume II is in press and will be available second
half of 2008.

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> From: "Heaton, Timothy HE" <[log in to unmask]>
> Reply-To: Stable Isotope Geochemistry <[log in to unmask]>
> Date: Wed, 13 Aug 2008 12:03:22 +0100
> To: <[log in to unmask]>
> Conversation: [ISOGEOCHEM] sodium azide preservative
> Subject: Re: [ISOGEOCHEM] sodium azide preservative
> 
> Alice
> 
> You would need to check that the potential decomposition products of
> sodium azide do not include any of the dissolved gases you want to
> measure (N2?).
> 
> Tim H.E. Heaton
> 
> NERC Isotope Geosciences Laboratory
> British Geological Survey
> Keyworth, Nottingham NG12 5GG, England
> (www.bgs.ac.uk/nigl/index.htm)
> 
> Tel. +44(0)115 936 3401
> Email: [log in to unmask]
> 
> 
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
> Behalf Of Alice Chang
> Sent: 12 August 2008 19:37
> To: [log in to unmask]
> Subject: [ISOGEOCHEM] sodium azide preservative
> 
> Hello Isogeochemists,
> 
> We are having a dilemma choosing a suitable preservative--mercuric
> chloride versus sodium azide--for seawater samples that will be analyzed
> for DIC and a variety of dissolved gases. The preservatives are used to
> prevent bacterial growth or anything that can affect the character of
> the seawater when it is collected. Diluted mercuric chloride is
> currently used, as that is the protocol. However, our new labs are
> moving towards zero-Hg tolerance (or as low as possible), and HgCl2
> presents a contamination source to colleagues doing Hg analyses. Azide
> is the alternative, but we have never used it. In concentrated form,
> azide appears to be reactive (explosive) with heavy metals and forms
> toxic fumes in contact with acids.
> 
> What concentration of sodium azide solution is usually used that is safe
> enough to prevent reactions with metals or acids? We don't want to be
> rinsing and diluting our water samples post collection because that
> would drastically affect the water's chemical make-up. For DIC analysis
> via coulometry, the water samples will be reacted with dilute phosphoric
> acid, and we don't want any adverse effects.
> 
> Thanks.
> Alice
> 
> 
> 
> --
> Alice S. Chang
> Post-doctoral Fellow
> School of Earth and Ocean Sciences
> University of Victoria
> 
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