HI All--

I switched our EA, Costech ECS 4010, over to sulfur mode (tungstic oxide 
oxidation column, pre-packed from Costech, teflon tubing, 2m GC column), 
and can't seem to get the SO2 to come out in a single peak.  Organic 
material, sulfanilamide or ground fish, gives two main peaks--a sharper 
early one at ~400 sec and another one (or more) broad one around 550 
sec.  Both sulfides and sulfates (with added tungstic oxide) only give 
the latter broad peak(s), regardless of sample size or added organic 
material.  The early peak is similiar to the what I was getting  the 
last time I ran sulfur (sulfides, sulfates, some sulfanilamide).

I've changed the transfer lines a couple of time (now bypassing Costech 
detector plumbing), cranked the hotplate under our conflo up, have the 
GC running at 110 (highest temp setting), swapped drying tubes, and have 
been playing with drop timing and oxygen amounts.  I'll  be swapping the 
ash collector and having at it again--but I would appreciate any 
suggestions.  Also are their any particular pitfalls to watch out for 
when running organic samples?  We're running ~8mg for the fish to get a 
reasonable signal (or what will be reasonable once we get a fairly clean 
peak). 

thanks in advance--

take care

gerry

p.s.  I was playing with PEEK tubing in place of teflon (lower gas 
permeability than teflon, don't heat gun PEEK).  It seemed ok in initial 
tests last time around, but it was one of the first items that got 
swapped out this time.  It's more expensive than teflon/PTFE tubing, but 
it may be a viable option if you require lower gas backgrounds.