Yes I did replace all the o-rings possible.  The 2 just under the  
valve and the three sealing the connections to the gas lines for both  
the purge and the s/sl.  That didn't seem to do the trick in this  
case unfortunately.

On May 10, 2006, at 11:46 AM, Brian Jones wrote:

> Hi Susan,
> Have you tried replacing the rubber o-ring just under the valve.  
> These rings
> are fairly cheap and I have found in the past that they tend to be the
> weakest link in the valve system.
>
> Brian Jones
> Stable Isotope Ecology Lab
> Texas A&M University
> College Station, Tx. 77843-3146
> 979-845-8916
>
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]]  
> On Behalf
> Of Susan Ziegler
> Sent: Wednesday, May 10, 2006 11:26 AM
> To: [log in to unmask]
> Subject: Re: [ISOGEOCHEM] GC-C-IRMS issues (split/splitless valve  
> leak)
>
> Thanks to everyone for their suggestions on our fractionation issue.
> It was much appreciated.
>
> It turns out that I have a leaking split/splitless on/off valve in
> the injector system. I have removed the valve in question and purged
> it with compressed air, taken it apart and cleaned it.  After that
> the leak was diminished but subsequently returned within 6 hours. In
> the past toggling the valve between split and splitless would fix the
> leak found in splitless mode and to prevent such leaking toggling
> every few days did the trick.  So this valve leaves much to be  
> desired!
>
> I am using an HP6890 (about 6 years old) and have just found out that
> I cannot purchase a new s/sl onoff valve through Agilent Technologies
> (the company that now makes the HP instruments) and instead have to
> purchase an entire manifold that the valve is mounted onto at a cost
> of $2300 USD.  Does anyone know where I might be able to find a new s/
> sl on/off valve (PN G1544-60710) for the 6890 split/splitless
> injector?  This is apparently an inherent problem with these
> injectors so I would really like to find out if there is an
> alternative to buying the very expensive manifold every time the
> valve fails.
>
> Thanks again for the input.
>
> All the best,
> Sue
>
>
> Susan Ziegler
> Associate Professor
> Department of Biological Sciences
> University of Arkansas
> Fayetteville, AR  72701
> 479.575.6944 (lab 6342)
> 479.575.4010 (fax)
> http://www.uark.edu/~susanz/

Susan Ziegler
Associate Professor
Department of Biological Sciences
University of Arkansas
Fayetteville, AR  72701
479.575.6944 (lab 6342)
479.575.4010 (fax)
http://www.uark.edu/~susanz/