Hello Everyone,

I have a rather interesting/annoying problem with 
my Isoprime-Multicarb system.  Essentially, 
during a run no gas is getting from the reaction 
vial to the first coldfinger (CF2).  At first we 
thought it was a problem with CF2 (e.g., either 
it was plugged or not cooling properly) but the 
problem still persisted after changing to a new 
coldfinger.  If we simply inject CO2 into the 
vial (bypassing the calcite-phosphoric acid 
reaction) we are able to get CO2 from the vial to 
CF2 and trap it correctly.  However, this works 
only if we are using a lot of CO2 gas.  If we use 
only a small amount (as if we reacted 100 ug 
calcite) it does not work.  I have confirmed that 
CO2 gas is being produced (i.e., no problem with 
the addition of acid to the vial).  So 
essentially, it appears that CF2 does not have 
the ability to "pull" the CO2 from the reaction 
vial or the CO2 gas is being trapped / lost 
somewhere along the way.  I have considered the 
possibility that the water trap is too cold (and 
that the thermocouple is reading incorrectly) and 
will check this today.

Here are a few more details.  I've checked the 
system for leaks with Argon and everything looks 
OK.  The needle and stainless steel tubing 
leading from the needle to the inlet system are 
not plugged with acid (...those of you with the 
multicarb know this is a common problem).  We 
have confirmed that the heated rack is at about 
90°C.  We are using a new batch of acid, but it 
worked fine for a few runs so I don't think this 
is the problem.  We also have the re-designed 
multicarb needle, but again we used this for a 
few runs without problem.

Any suggestions would be greatly appreciated.

Jennifer


-- 
Post-doctoral Researcher
Centre GEOTOP, Universite du Quebec a Montreal
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