Hello,

I am using IAEA-NO3 (+4.7 permil KNO3)as a standard for an EA-DeltaPlus. If
I use this the N peak gets quite broad (80 seconds) compared to a plant
sample (55 seconds) and it is tailing much more. If I use IAEA-N1 (+0.4
permil (NH4)2SO4) I also get a nice peak of 55 seconds. Earlier on I also
had a nice peak for IAEA-NO3, and now it suddenly has changed, also the
delta value is changed by ± 0.8 permil. I checked all the reactors and
traps and this seems OK.

As there is no CO2 peak for KNO3 I can't check on this. I added a little
carbon to the IAEA-NO3 and then the peak looks a lot better. So the cause
may be a too slow burning of the KNO3. Does anyone have experience with this?
Als suggestions are welcome.


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Richard van Logtestijn
Vrije Universiteit
Faculty Biology
Department of Systems Ecology
De Boelelaan 1087
1081 HV Amsterdam
the Netherlands
tel +31 20 4447247
fax +31 20 4447123
e-mail : [log in to unmask]
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