Hi Paul,
Thanks for the reply. Can you shoot me
your vendors off list for your 0.5mm ID tubes and zero dead volume fitting? I
absolutely hate how many tubes I break every time I need to change the reactor
and would be forever grateful if there is a way to avoid this. I would even go
so far as to say you would deserve some kind of international humanitarian
award for this information!
Regarding the peak broadening issue, this
is also something I’ve considered, but I guess I’ve always assumed that
the transition from a small diameter capillary to the large diameter ceramic
tube would trump the turbulence introduced by the wire in terms of
chromatography (but I could be absolutely wrong, just my assumption).
Thanks again for the thoughtful comments.
Mike
From:
Sent: Wednesday, March 26, 2008
5:12 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] DIY
Oxidation Reactor -- Better Chromatography with Smaller Tubes?
Mike,
You need not reduce your tubing OD. With a proper zero volume fitting, it can
be any size you desire without affecting the chromatography. We have built our
ovens around a 1/8" OD ceramic tube (0.5mm ID) and no longer worry about
breaking tubes as we tighten fittings.
Also, I've often wondered though if the peak broadening due to ovens isn't more
due to the wire in the tube than the ID of the tube. Does the wire cause
broadening by disrupting laminar flow?
Paul Eby
At 01:47 PM 26/03/2008, you wrote:
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
M/S 239-4
Bldg. N239, Room 327
(650) 604-6110