Bob, the information you have provided is very useful to us.
Thank you,
Yi Wang (Ph.D.)
Director, Isotope Laboratory
ZymaX Forensics
600 S. Andreasen Drive, suite B
Escondido, CA 92029
Email: [log in to unmask]
Tel: 760-781-3338 ext 43
Fax: 760-781-3339
Cell: 609-721-2843
http://www.zymaxusa.com
-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
Behalf Of Vocke Jr., Robert D.
Sent: Monday, October 05, 2009 2:02 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] 37Cl/35Cl abundance ratio of SMOC?
Dear Dr. Wang,
There is, unfortunately, no absolute 37/35Cl value for SMOC as it is in
itself variable. Standard Mean Ocean Chloride was thought originally to
be homogeneous but recent measurements have shown variations of up to a
per mill for ocean water. Basing the Cl isotopic scale on universally
available but variable scale artifact is not a good way to make precise
measurements.
I would recommend that you use the NIST SRM 975a. It has an absolute
37/35Cl ratio of 0.31970 +/- 0.00048 and is as isotopically homogeneous
as any of the solid isotopic reference materials sold by NIST. You can
get a copy of the certificate and other information on this SRM at the
NIST SRM website:
https://www-s.nist.gov/srmors/view_detail.cfm?srm=975A
I hope this helps,
Regards,
Bob Vocke
Robert D. Vocke, Jr., Ph.D.
National Institute of Standards and Technology
Analytical Chemistry Division
Inorganic Chemical Metrology Group
100 Bureau Drive, MS 8391
Gaithersburg, MD 20899-8391
301.975.4103 (work)
301.869.0413 (fax)
[log in to unmask]
http://www.cstl.nist.gov/nist839/index.html
-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
Behalf Of Yi Wang
Sent: Friday, October 02, 2009 12:30 PM
To: [log in to unmask]
Subject: [ISOGEOCHEM] 37Cl/35Cl abundance ratio of SMOC?
Dear ISOGEOCHEMERS,
Could anyone help provide the exact 37Cl/35Cl abundance ratio for the
SMOC standard? I mean a more accurate ratio better than "0.324" itself?
It is needed to develop a more convenient method for compound-specific
chlorine isotope analysis on our GC-MSD.
Thanks a lot,
Yi Wang (Ph.D.)
Director, Isotope Laboratory
ZymaX Forensics
600 S. Andreasen Drive, suite B
Escondido, CA 92029
Email: [log in to unmask]
Tel: 760-781-3338 ext 43
Fax: 760-781-3339
Cell: 609-721-2843
http://www.zymaxusa.com
|
