Take a look at the archives about this problem and use of quartz inserts or inconel metal inserts.  As recent as a few months ago.  Jason 

Jason Curtis, Ph.D.
Stable Isotope Mass Spec Lab manager
Senior Associate-In Geochemistry
Department of Geological Sciences
University of Florida
Gainesville, FL 32611

On Apr 12, 2017, at 9:36 AM, wissel2b <[log in to unmask]> wrote:

Hello Sofia,
GFF and GFC filters melt at 1000 C. We analyze POM on filters at 820 C instead without any problems. I'll send you a paper later today.
Cheers, Bjoern

On Apr 12, 2017, at 5:08 AM, Sofia Goncalves <[log in to unmask]> wrote:

Dear Isogeochem members,

We are analysing some difficult samples of POMs for d15N and d13C on our EA 2000 IRMS Delta V Advantage. These samples are colleted and analyzed on filters and have a high C/N.

Some of these samples gives peaks with strange shape and integration. The separation is not good either.

The analytical conditions are as follows:
- carrier flow 90ml/min
- oxygen flow: 200ml/min
- reference flow: 200ml/min
- ox. reactor: 1020 Celsius
- red. reactor: 650 C
- oven: 45 C

Could anyone help me improve this type of analysis?

Thank you very much.

Best regards,