We use similar containers, except that we seal the tops with
Geo-Microbial Technologies septa. If you over-pressurize the samples
(e.g., put 20 or 30 mL gas into a 10 mL vial) they store well for
extended periods of time. I performed a test where I re-analyzed a few
samples (~6) for 13CH4 after ~1 year of storage and the 13C values were
within the range of error for the instrumental analysis. Of course, it
is probably preferable to run the samples within a few weeks or months,
but you could store them longer if you're backed up.
Yit
PS - keep in mind that the actual volume of many wheaton serum vials
exceeds the stated volume. For example, I think the 10 mL vials have an
actual internal volume of 12-13 mL, depending on the septa you use.
Paul Eby wrote:
> We use Wheaton bottles with crimp seal tops. The normal septa for
> these bottles are somewhat thin, and will leak through needle holes.
> You can purchase thicker septa (13mm) from Bellco Glass. These septa
> seal very well, and can even hold a vacuum for weeks.
>
> We use this for atmospheric CO2 and CH4.
>
> Paul Eby
> University of Victoria
>
>
> At 12:47 AM 16/10/2006, you wrote:
>> Dear list members!
>>
>> We plan to take gas samples in order to analyse d13C of respiration in a
>> rather remote area next summer. Storage of samples up to 2 months
>> will be
>> necessary. From our own experience, we know that air samples in
>> excetainer
>> tubes are leaking quite a lot. Are there some possibilities, ways,
>> tricks,
>> to store gas samples for 13C analysis for a longer time period?
>>
>> We are happy about any recommendations!!
>>
>> Thanks
>>
>> Christina Biasi
>
--
...I do not believe totality can be contained in language; my problem is what remains outside, the unwritten, the unwritable. - Italo Calvino, If On a Winter's Night a Traveller
Yit Arn Teh, Ph.D.
Postdoctoral Scholar
Rhew Laboratory
Department of Geography
507 McCone Hall
University of California
Berkeley, CA 94720-4740
Email [log in to unmask]
Office +1 (510) 643-6984
FAX +1 (510) 642-3370
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