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/