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Mon, 2 Jun 2008 09:46:51 +1000 |
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Dear List Members
As I understand it, the Isodat software does not include m/z30 in its
calculation of del15N/14N and thus this step has to be done off-line. Using
the the peak areas from Isodat and the equation del =
[(Rsample/Rstandard)-1]*1000, I get a value of 63 per mil for air. I feel
I'm making a simple mistake somewhere, but can't think where. Can someone
please point me in the right direction?
Also, I've just started measuring CO2 on a Trace GC Ultra with a 25m
Poraplot Q column. The samples are headspace gas from sediment core
incubations. The GC method I'm using is isothermal (35C). There are two
peaks, the first of which is all m/z46 and tends to be non-Gaussian, the CO2
peak elutes second at about 150s. Would the first peak be NO2? Why would the
peak shape be so poor?
Thanks in advance for the help!
Melissa..
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Melissa D. Bautista
IRMS Research Technician
Centre for Coastal Biogeochemistry
Southern Cross University
P.O. Box 157 Military Road
Lismore NSW 2480 Australia
phone: +61 266 269 565
mobile: +61 431 928 278
email: [log in to unmask]
************************************
audaces fortuna iuvat
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