Re: EA troubles: NA1500

A couple of (long-shot) suggestions:

1. have you independently checked the temperature of your furnace? and

2. what reactor packing are you using?  Are you using the WO3 & Cu packing, or the Cu-only packing?  A long time ago I used to use the WO3 & Cu packing, but it would sometimes give me SO2 chromatography problems that drove me to distraction (IPA-distraction, not lolly-distraction, in my case).  Since switching to the Cu-only configuration, and adding V2O5 to each sample, I've generally had good SO2 chromatography.

Good luck!


Simon Poulson
Research Professor
Dept. of Geological Sciences & Engineering MS-172
University of Nevada - Reno
1664 N. Virginia St.
Reno, NV 89557-0138. USA
(775) 784-1104
Fax: (775) 784-1833
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Questions for NA1500 users.
I am still battling my EA which is smearing my sulfur peak over 200 seconds instead of the usual 50.  I have tried all the usual things to no avail.
BUT I have now determined that I have a compressed air leak where the line feeds into the EA. The culprit is the little double block of aluminium which the compressed air and oxygen and He lines immediately feed into once entering the EA.  The manual labels the blocks as a 'safety line' which consists of a single effect microcylinder and two, 2 way single effect microvalves.   The manual does not mention them at all in the spares list. The air is coming out of the little hole at the top of the block and also where both the blocks join together, which leads me to ask.
1.      Is it normal for the aluminium blocks of the safety line to leak compressed air at all times?
2.      Is this likely to cause enough of a problem to prevent the bimatic valve operating properly? Given that the compressed air gauge at the front of the EA reads as it should and is Teed in before the safety line.
3.      I have measured the oxygen flow at the oxygen vent at the front of the EA and it is ALWAYS 25ml/min, even when doing an oxygen injection.  Should the flow from the oxygen vent slow down or stop when the bimatic valve is actuated?
4.      Could my poor peak be a result of the oxygen regulator not working properly?  I notice that the pressure gauge gives a dramatic jump when the bimatic valve is closed although this may have always happened. J
There is also a small leak in the micro-solenoid valve that powers the sample carousel but this does not appear to cause any problems.
If anyone has any insights they would be greatly appreciatedŠ.  Because of this I have become a highly valued customer at the lolly shop and I don't think that that is good for my sugar levels  J
Kim Baublys
Stable Isotope Geochemistry Laboratory, Earth Sciences
The University of Queensland, 4072
Ph   +61 7 3365 1131
Fax +61 7 3365 1277