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