Hi Tim,


I haven't made this experience yet with CO but on my old Delta S source I
had to keep the source heaters on all the time to prevent peak tailing of
CO2 because the source ceramics "soaked" up CO2.

I didn't see this effect for N2 and what with N2 and CO being similar in
mass and size, I wonder if your "problem" is caused by source ceramics. That
doesn't mean to say heat annealing the ceramics after cleaning them can be
ignored.

Given that you say the CO peaks are also slow to rise, I am wondering if the
GC column might be the source of your problem. When's the last time you
baked out the column; for how long and at what temperature?


Cheers,

Wolfram


> -----Original Message-----
> From: Stable Isotope Geochemistry
> [mailto:[log in to unmask]] On Behalf Of tcp121
> Sent: 27 June 2005 17:17
> To: [log in to unmask]
> Subject: Ion Source Cleaning
>
>
> Greetings...
>
> When cleaning the ceramics of the ion source for our Delta
> Plus XL I used a bead blaster to get rid of the ion burn
> rather than a diamond file. The end result is the same. But
> the next step in the procedure (found in the manual) is to
> anneal the ceramics. Does anyone know the reason for
> annealing? I wonder if it closes off pore spaces in the
> ceramics that are exposed when abrasively cleaned. The
> reason I think this is that I did not follow this step, and
> now my CO peaks on the Delta are now slow to rise and slow to
> fall, as if some CO is getting trapped in the system somewhere.
>
> Any thoughts? Is annealing necessary?
>
> Thanks...
>
> Tim Prokopiuk
>
> -----------------------------------------------
> Tim Prokopiuk
> B. Sc. Geology/Technician
> Saskatchewan Isotope Laboratory
> Room 241
> Department of Geological Sciences
> University of Saskatchewan
> 114 Science Place
> Saskatoon, Saskatchewan, Canada
> S7N 5E2
> Phone: (306) 966-5712
> Fax: (306) 966-8593
> Email: [log in to unmask]
>