Good Day Rich,

I trust you have a EA/Delta V Plus set up. If not read no further but might be useful for others. We had very similar issues in 2015 with our dual measurements CO2 ref values thinking it was due to jump calibrations or magnet calibrations errors or…. We ended up doing individual N and C only measurements.
The solution was to have the Delta’s electro magnet removed, cleaned and plates inserted to shield it from the Aluminum housing. Apparently it accumulates sticky static particles. This definitely did the trick after long troubleshooting days.

Hope this helps


From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Dabundo, Richard C
Sent: Wednesday, January 25, 2017 5:41 PM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Elemental Analyzer CO2 reference peaks


I'm having an issue with CO2 reference peak deviation during an Elemental Analyzer N and C run. Two CO2 reference peaks are produced following the C sample peak. Originally, the first peak was consistently ~1.1‰ lighter than the second peak. After creating a new N2 to CO2 jump calibration, the first reference peak became consistently heavier than the second by about 0.6‰. We have sufficient distance between the sample and reference peaks, and the same issue results even if no samples are loaded. CO2 on-offs are fine, with a standard deviation of about 0.04‰. Does anyone know what may be causing our disparity?


Rich Dabundo