Hi Mike,

Making the combustion reactors is not too difficult.  For our 0.5mm ID
ceramic tube reactors, we usually twist 0.1mm wires together (1 Cu, Ni,
Pt, each) and then pack it in.

There is also another option to make your own, lower dead volume
combustion reactors.  You can slide the metal wires of interest into a
deactived fused silica capillary (i.e. 0.53mm ID, or 0.32mm ID, etc), and
secure the metal filled region in your hot zone.  This way you do not need
fittings near the ends of the reactor.

In this case, depending on the i.d. of the tubing you are packing, the use
of a 0.1mm wire is used over a 0.05mm wire because kinking increases with
the smaller diameter wire during packing, thus making it more difficult to
pack.

I won't go into the details, information on different setups have been
published:

References
1.	Goodman, K. J., Hardware Modifications to an Isotope Ratio Mass
Spectrometer Continuous-Flow Interface Yielding Improved Signal,
Resolution, and Maintenance. Anal Chem 1998, 70, 833-837.

2.	Sacks, G. L.; Zhang, Y.; Brenna, J. T., Fast Gas Chromatography
Combustion Isotope Ratio Mass Spectrometry. Anal Chem 2007, 79, 6348-6358.

One thing to keep in mind is, the capillary form is generally more fragile
than the ceramic tube variety, but generally promotes better
chromatography.

Good luck,
-Herb
Cornell University


> Has anyone had experience with building their own oxidation reactors
> with smaller ID tubing to improve their chromatography during the
> combustion process?  I know how much of a pain it is to change these
> reactors, and while a smaller ID/OD tubing will probably increase the
> chances of breakages during replacement (not to mention potentially
> decrease the life span of the reactor), for certain types of analyses
> the performance gain may make up for it.
>
>
>
> Also, is there a reason most users go with the 0.1 mm wires instead of
> something a little thinner (say 0.05mm) to increase the packing
> efficiency (and thereby reduce dead volume) and also surface area?
>
>
>
> I have to admit that this is the first time I've ever had to purchase
> reactors from Thermo (I inherited a stock from the previous technician)
> and I actually laughed at the customer service rep who gave me the price
> over the phone...
>
>
>
> Thanks in advance,
>
> Mike
>
>
>
>
>
> ************************************************************************
> ****************************************************************
>
> Michael D. Kubo
>
> NASA Ames Research Center
>
> M/S 239-4
>
> Bldg. N239, Room 327
>
> Moffett Field, CA 94035
>
>
>
> (650) 604-6110
>
>
>
>