Hi Paul,

our IRMS (20-20 Europa Scientific) has a reduction tube with an oven
temperature of 600 °C. For regeneration of the copper we just cool down the
oven to 400 °C, disconnect the tube on both sides and flush the tube with
5%H2 / 95%N2  (flow rate ca.1000 ml/min) after about 15 min the copper is
visibly reduced (the copper is orange again and only the lowest part is
still black). This cooper tube will last about 240 sample. It is possible to
regenerate the tube about 20-30 times. After regeneration we reconnect the
tube and heat the oven to 600 °C. Usually it takes about 2 hours helium flow
(flushing flow rate), till our system is clean.We run a test sample to
controll the HT and the 2/1 ratio. If the 2/1 ratio is too high, we flush
longer. Mass 30 background is higher after regeneration, but it gets to a
normal level after a while.
For our N-analyser (Makro-N Elementar) we have a regeneration furnace called
"cuRE" . It regenerates ca.1,4 kg copper in 10 hours, has a flow meter (flow
rate 3,5 l/min), an intern heater and a gas stop (timer). We regenerate the
cooper for the N-analyser only two times.(Our N-analyser needs a much better
cooper quality than our IRMS, if we regenerate the cooper more than two
times it will be used up after a few samples).

Best regard,
Claudia Schuetz

Chair of Plant Nutrition
Department für Pflanzenwissenschaften
Wissenschaftszentrum Weihenstephan
Technische Universität München
Am Hochanger 2
85350 Freising

----- Original Message -----
From: "Leo Mayr" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 20, 2006 3:59 PM
Subject: Re: [ISOGEOCHEM] copper regeneration


> Hi Paul
>
> As one of the scientist working in the lab of the IAEA in Seibersdorf I
> just want to add a few points to Nik's e-mail:
>
> Since a few years we do not use pure H2 anymore. We now use 10%H2 in N2
> (I now sleep much better). The german name of this mixture is Formiergas
> (I don't know the english name but it is normally used for welding
> purpose). We just take the hot tube (650C) out of the EA, place it on
> self-made holder and connect it to the cylinder. The whole regeneration
> takes not more than 10min. A Cu filling can be regenerated up to 20
> times but the capacity of the tube drops down to about 70-80 samples at
> the end of the lifetime. To prevent sintering we mix the Cu with about
> 20% quartz chips.
>
> Regards
>
> Leo Mayr
> FAO/IAEA Agriculture and Biotechnology Laboratory
> Soil Science Unit
> A-2444 Seibersdorf, Austria
> Tel. (+43 1) 2600 28305
> Fax (+43 1) 2600 728305
> [log in to unmask]
>
>
>
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
> Behalf Of Nik Binder
> Sent: Thursday, 19 January 2006 00:06
> To: [log in to unmask]
> Subject: Re: copper regeneration
>
> Hi Paul:
>
> Many years ago I had a chance to spend a week working with scientists at
> the IAEA lab in Seiberdorf, Austria (just outside of Vienna).  At that
> time they had an ANA-Sira connected to a Carlo Erba EA (I believe an
> NA1500) with a splitter valve.  They were measuring m/e 30 to monitor
> it's increase to indicate when the copper was no longer converting all
> of the N2 compounds to
> N2 gas.  At a certain level they would remove the reduction tube (while
> it was still hot) and then they would connect it to a H2 gas cylinder.
> They would regenerate the reduced copper for several hours and then
> re-introduce the reduction tube back into the EA.  This generation EA
> had the tapered combustion/reduction tube.  My understanding was that
> this regeneration was not as effective as replacing the copper with
> fresh reduced copper and I have not come across anyone else that has
> tried to regenerate their own copper.  Although the method of
> manufacturing reduced copper would be similar ie. a batch of copper is
> heated as H2 gas is flushed over the copper.  Is suspect that overnight
> regeneration would be more beneficial.  I don't remember the H2 being
> used was anything than pure H2 and of course there was the danger of
> explosion.
>
> I think for the price of reduced copper, it may not be worth while for
> everyone to set up a system of regenerating their copper.  Trying to do
> this with the reduction tube in place would add additional hazards
> especially if the reduction tube cracked during the process.
>
> Regards
> Nik
>
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
> Behalf Of Paul Brooks
> Sent: January 18, 2006 4:39 PM
> To: [log in to unmask]
> Subject: Re: copper regeneration
>
> Elemental Analyzer users:
>
> I have just been given a tank of 5% H2 in N2 that in principle should be
> able to regenerate oxidized copper in an elemental analyzer.
>
> I used to do this with pure H2 and a bypass valve system to isolate the
> H2 from coming into contact with the air.  Eventually I gave it up as
> too dangerous, and buying finer copper solved the problem.  However, as
> I recall several EA users did this with a 5% H2 in N2 mix as in
> principle this mixture should not be flammable in air.
>
> Does anyone have any words of wisdom on this?  It would seem easy enough
> to simply disconnect the top of the copper column and let it vent to
> atmosphere, then connect the 5% H2 mixture to the bottom of the tube.
> Any idea how long it will take to regenerate?  Also, I recall from
> previous discussions that there might be a problem with N isotope
> precision immediately after regeneration.
>
> Any words of wisdom will be greatly appreciated, including warnings not
> to try it!
>
> Thanks in advance, Paul Brooks.
>
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