Dear Jonelle,


Mike is right problem come from oxygen trapped by copper. To increase analysis quantities it is necessary to increase copper reaction surface area!

You can do that by increasing the weight of electrolytic copper but the best is to use copper wires that is electrolytic copper oxidize by oxygen and reduce by hydrogen. Chromium oxide plus silver cobaltous oxide is the best oxidation mean you can get in your furnace. Note Silver is here to trap halogen. But with this packing it is necessary to use separate tube in your chn normally built with 2 tubes furnace . Like this you can put a big quantity of copper wire (stick) which normally allow you to run around 800-1000 samples.

Most of French laboratories involved in Isotope ratio measurement adventure around 25 years ago used this configuration.

Due to hazardous of this reagent CHNOS manufacturers decided to change them to return to copper oxide. Just keep in mind that copper oxide.

Note that tungstate trioxide was developed for get Sulfur with CHN.

If the oxidation of you sample are ok you can continue to use it in oxidizing tube and file the reduction one with reduce copper wire.

I was involved in and continue to be in production, development and sales of this reagent and capsules for CHNOS.

Where are you located?


Best Regards


Laurent Bertal



Courtage Analyses Services

14, Rue des Mouettes    F-76130 Mont Saint Aignan     FRANCE

Tel: +33 2 35 07 60 00        Port. : + 33 6 09 67 45 69      Fax. : +33 235 706 439

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De : Stable Isotope Geochemistry [mailto:[log in to unmask]] De la part de Mike Elefante, Elf Analytical Services
Envoyé : lundi 9 janvier 2017 23:11
À : [log in to unmask]
Objet : Re: Reactor column used for bulk C/N analysis using the Flash HT plus EA




 200 samples out of a single tube reactor is not too bad. There are many ways to pack them, if you are running the same material all the
time you need to optimize the packing for that type of sample. If you are running many different types of samples it is harder to optimize. If you use chromium oxide and silvered cobaltous you can recycle these chemicals and save lots of cash and hazardous waste. I would use these two chemicals. Usually when a tube fails it is the copper or to much ash buildup. You can increase the life of the copper by injecting less oxygen. Any oxygen not used for your combustion reaction is using up your copper. Give me a call and I will help you optimize your setup.

Mike Elefante, President

Elf Analytical Services, Inc



-----Original Message-----
From: Jonelle Herman - NOAA Affiliate <
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Sent: Mon, Jan 9, 2017 3:41 pm
Subject: [ISOGEOCHEM] Reactor column used for bulk C/N analysis using the Flash HT plus EA

I was wondering if anyone has had success using a reactor built with chromic oxide, silvered cobaltous, and copper wires, when running bulk C/N analysis on the Flash HT plus EA?  We are currently using the pre-packed reactors with tungstic oxide and electrolytic copper wires. With that reactor we are only able to get about 200 samples through before having to change it out.  We were hoping that if we switched to using the reactor pre-packed with chromic, silvered cobaltous, and copper wires we might get more samples through before having to replace it.


Any advice with this would be appreciated!







Jonelle B Herman

Scientist V, 

(Lynker Technologies Contractor)

Environmental and Fisheries Science Division,

Northwest Fisheries Science Center, 

National Marine Fisheries Service,

National Oceanic and Atmospheric Administration, 

2725 Montlake Blvd. E., Seattle, WA, 98112, USA.


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