At SAC Edinburgh  (Keith Smiths group) we used glass syringes with vacuum
greese for field gas greenhouse gas collection in the UK with 3 way luer
lock plastic fittings on the  and then clipped on to a board for ease of
collection  and prevention of bumping,  these were fine for about one day.
The greenhouse gas group there has done extensive studies of the gas
tightness of various materials for long term storage stainless steel proved
best they also found that a metal loaded epoxy poxy putty  RS 850-978 was a
good gas tight seal for any joints. They have developed wonderful automated
gas collection systems thanks to the excellent work Albert Scott and Ian
Criton I think they may be for sale too. If anyone is interested his email
is [log in to unmask]   I hope he doesn't kill me for posting this  but I
don't think he would be on the isogeochem list.
Hope that's of some help
Rebecca Hood


> ----------
> From:         Paul D. Brooks.[SMTP:[log in to unmask]]
> Sent:         Monday, December 14, 1998 11:25 PM
> To:   [log in to unmask]
> Subject:      Re: USE OF GAS-TIGHT SYRINGES FOR SAMPLE COLLECTION AND
> STORAGE
>
> I have not used syringes for isotope ratio gas collection, but we do use
> nylon ones lubricated with vacuum grease, for gas concentration
> collection.
>  The problem is that most plastic syringes diffuse gas very rapidly, and
> even the nylon ones are only reliable for a most a few days.  I assume
> glass syringes sealed with vacuum grease might work.
>
> Paul Brooks.
>
>
> At 08:41 AM 12/10/98 -0800, you wrote:
> >QUESTION FOR ALL:
> >
> >We are thinking of using gas tight syringes configured with two way
> >valves for the collection and storage of soil gas samples for
> >isotopic abundance analysis of carbon, nitrogen and oxygen.  Anyone
> >out there have any experience or recommendations as to this approach?
> > Any advice would be much appreciated.
> >
> >Bill
> >
> >*******************************************************
> >William L. Griffis
> >Chemist
> >Integrated Stable Isotope Research Facility (ISIRF)
> >Terrestrial Plant Ecology Branch
> >Western Ecology Division
> >National Health and Environmental Effects
> >Research Laboratory
> >US Environmental Protection Agency
> >200 SW 35th Street
> >Corvallis, Oregon 97333
> >Telephone:  541-754-4761   FAX:  541-754-4799
> >E-mail:  [log in to unmask]
> >*************************************************
> >
> >
>