HI All--

Our Costech EA seems to be pushing the O2 slug through immediately (<2 
secs).  We've run it for years with ~9 sec delay, and just the other day 
it seems that the drops are missing the O2--and just catching it if it's 
set to a 1 sec delay.  Background levels lower and peaks are smaller 
than expected, but the N2 is coming out a little early.  Sort of like 
when a seam opens up in the oxidation reactor, but without affecting the 
flow rate downstream.

He flow rates seem reasonable, ~75 mL/min, valves seem to be switching 
as expected--He switches to oxygen block, goes through correct line 
(e.g. micro), to bottom block, and flow to ZeroBlank is only restored 
when O2 loop reconnected (during time it flushes loop).  He and O2 
pressure on Costech around 12 psi--in the normal range. 

Switched O2 tanks--nada.

I will be switching out reduction tube (it's dead), and I've baked out 
the GC column.

Thanks in advance for any advice--yes, I'm bad at posting thanks 
afterwards...

Back to beating my head against the wall (and leak checking)....

take care

gerry

p.s. yeah, I may just swap out everything...