Hi Rick,
How about using another type of filters? I think there are cellulose-based filters and polystyrene-type filters. I also recall electron microscopy pictures which revealed that they looked very different on the microscale: while the cellulose ones look like a net of fibers, the polystyrene ones look like a clean surface pierced by a lot of holes, as if someone had shot through it with a gun. Could this solve your problems?
Best wishes, Martin
_________________________
Dr. Martin Elsner
Helmholtz Young Investigator Group Leader
Institute of Groundwater Ecology
Ph.: +49-89-3187-2565
Fax: +49-89-3187-3361
e-Mail: [log in to unmask]
Helmholtz Zentrum München
German Research Center for Environmental Health (GmbH)
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85764 Neuherberg
www.helmholtz-muenchen.de
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-----Ursprüngliche Nachricht-----
Von: Stable Isotope Geochemistry [mailto:[log in to unmask]] Im Auftrag von ISOGEOCHEM automatic digest system
Gesendet: Dienstag, 4. November 2008 06:09
An: [log in to unmask]
Betreff: ISOGEOCHEM Digest - 2 Nov 2008 to 3 Nov 2008 (#2008-250)
There is 1 message totalling 237 lines in this issue.
Topics of the day:
1. cryogenic extractions, filtering with charcoal, laser spectroscopy
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Date: Mon, 3 Nov 2008 11:45:20 -0700
From: Richard Doucett <[log in to unmask]>
Subject: cryogenic extractions, filtering with charcoal, laser spectroscopy
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Hi All,
We are preparing to cryogenically extract water from organic samples
(soils, plant leaves, stems, etc.), and we plan to run these water
samples for O and H isotopes on our cavity-ring-down laser instrument.
I have heard that people place activated charcoal in the collection
vials to remove the organics from the extracted water samples, and then
use 0.45-um syringe filters to remove the charcoal prior to isotope
analysis. Our problem is that, in the past, we have used 0.45-um GHP
syringe filters on water samples prior to analysis, but found that these
filters released fibers into the water samples, and that these fibers
would eventually coat the mirrors inside the laser instrument, affecting
precision and yield.
Here our are 3 concerns...
1. If we don't use charcoal to trap the organics, we risk gumming up the
heated injector port on the laser instrument.
2. If we use charcoal to trap the organics, but don't filter out the
charcoal prior to analysis, we risk plugging the micro-liter syringe on
the instrument.
3. If we filter out the charcoal with a syringe filter, we risk
releasing fibers into the laser instrument.
I would like to ask how other labs are prepping water samples (that have
been cryogenically extracted from plant samples) for laser spec analysis?
Cheers, and thanks in advance for any insight.
Rick
--
/Richard (Rick) Doucett, Ph.D., Associate Director
Colorado Plateau Analytical Laboratory
Northern Arizona University
Tel: 928.523.0967 (lab)
Tel: 928.523.7265 (office)
Fax: 928.523.7500/
/ /
/Stable Isotope Lab: http://www.isotope.nau.edu/
/Analytical Lab: http://www.research.nau.edu/cpal//
/ /
/Mailing address for packages:
Dept. Biological Sciences
Northern Arizona University
Building 21, South Beaver Street
Flagstaff, AZ, 86011-5640/
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Hi All,<br>
<br>
We are preparing to cryogenically extract water from organic samples
(soils, plant leaves, stems, etc.), and we plan to run these water
samples for O and H isotopes on our cavity-ring-down laser instrument.
I have heard that people place activated charcoal in the collection
vials to remove the organics from the extracted water samples, and then
use 0.45-um syringe filters to remove the charcoal prior to isotope
analysis. Our problem is that, in the past, we have used 0.45-um GHP
syringe filters on water samples prior to analysis, but found that
these filters released fibers into the water samples, and that these
fibers would eventually coat the mirrors inside the laser instrument,
affecting precision and yield.<br>
<br>
Here our are 3 concerns...<br>
1. If we don't use charcoal to trap the organics, we risk gumming up
the heated injector port on the laser instrument.<br>
2. If we use charcoal to trap the organics, but don't filter out the
charcoal prior to analysis, we risk plugging the micro-liter syringe on
the instrument.<br>
3. If we filter out the charcoal with a syringe filter, we risk
releasing fibers into the laser instrument.<br>
<br>
I would like to ask how other labs are prepping water samples (that
have been cryogenically extracted from plant samples) for laser spec
analysis?<br>
<br>
Cheers, and thanks in advance for any insight.<br>
Rick<br>
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<p class="MsoNormal"><i style=""><span
style="font-size: 10pt; font-family: Arial;">Richard (Rick) Doucett,
Ph.D.,
Associate Director<br>
Colorado Plateau Analytical Laboratory<br>
Northern Arizona University<br>
Tel: 928.523.0967 (lab)<br>
Tel: 928.523.7265 (office)<br>
Fax: 928.523.7500<o:p></o:p></span></i></p>
<p class="MsoNormal"><i style=""><span
style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></i></p>
<p class="MsoNormal"><i style=""><span
style="font-size: 10pt; font-family: Arial;">Stable Isotope Lab:
<a class="moz-txt-link-freetext" href="http://www.isotope.nau.edu">http://www.isotope.nau.edu</a><o:p></o:p></span></i></p>
<p class="MsoNormal"><i style=""><span
style="font-size: 10pt; font-family: Arial;">Analytical Lab:
<a class="moz-txt-link-freetext" href="http://www.research.nau.edu/cpal/">http://www.research.nau.edu/cpal/</a><o:p></o:p></span></i></p>
<p class="MsoNormal"><i style=""><span
style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></i></p>
<p class="MsoNormal"><i style=""><span
style="font-size: 10pt; font-family: Arial;">Mailing address for
packages:<br>
Dept. Biological Sciences<br>
Northern Arizona University<br>
Building 21, South Beaver Street<br>
Flagstaff, AZ, 86011-5640<o:p></o:p></span></i></p>
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End of ISOGEOCHEM Digest - 2 Nov 2008 to 3 Nov 2008 (#2008-250)
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