Hi Jonelle,

We've been able to run ~500 samples  (more for plant-only analyses) using chromium (III) oxide and copper wires with a liner insert to assist in removing ash (personally, the ash-removal tool from Thermo doesn't remove that much ash). I've found that the ash build-up is more problematic than chromic vs tungstic oxide. The type of sample significantly affects your #analyses as well. Plant samples are easy to run, whereas sediments will burn out your reactor much faster.  



Bethany Theiling, Ph.D.
Assistant Professor, Geochemistry
Department of Geosciences
University of Tulsa
800 Tucker Drive
Tulsa, OK 74104

From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of Jonelle Herman - NOAA Affiliate <[log in to unmask]>
Sent: Monday, January 9, 2017 2:40 PM
To: [log in to unmask]
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.