And need I say, after effecting the repair, you can re-process the affected results with a defined integration window for N2 that excludes the ref gas injections?



From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Rodrigo Maia
Sent: Friday, 6 May 2011 3:52 a.m.
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Type Mismatch Error


Hi Bob,


Yes, that usually means a damaged / old VG-GVF003 ferrule (that’s where the valve plunger seats).

You’ll probably have to replace the ferrule and the capillary attached to it.

Refer to the Isoprime’s Reference Injector Manual. It is pretty straightforward.







Rodrigo Nascimento Maia


Laboratory Technical Supervisor

SIIAF - Stable Isotopes and Instrumental Analysis Facility

Fundação da Faculdade de Ciências de Lisboa

Universidade de Lisboa


T: +351 21 7500619 (direct) ; internal: 22119




SIIAF – Stable Isotopes and Instrumental Analysis Facility

Faculdade de Ciências de Lisboa – Departamento de Biologia Vegetal

Edifício C2 – Sala 2.1.16

Campo Grande

1749 016 Lisboa




De: Stable Isotope Geochemistry [mailto:[log in to unmask]] Em nome de Robert Michener
Enviada: quinta-feira, 5 de Maio de 2011 16:38
Para: [log in to unmask]
Assunto: [ISOGEOCHEM] Type Mismatch Error


Hi all,


This is aimed at all the IsoPrime users who’ve experienced the dreaded type mismatch error.  I’ve been running dual gas CN runs and the other night things started to go haywire.  Carbon values are dead on, but nitrogen results started to experience type mismatch errors (7 in a run of 100).  When I looked at the chromatograms, the ref gas peak is either not there or is very jagged;  as a consequence, MassLynx thinks the ref gas peak is actually a sample peak. 


I’ve done a bunch of nitrogen stability runs and the chromatograms are not pretty (I can email a copy to anyone interested off list).  Carbon stability runs are nice, flat and smooth.  Based on my search of the archives, it looks like the nitrogen ref gas valve is sticking.  Has anyone taken one of them apart?  Air pressure is fine, and since carbon is stable, I don’t think it’s a dirty source.


Any advice would be greatly appreciated!







Robert Michener

IRMS Laboratory Manager

Boston University Stable Isotope Laboratory

Department of Biology

5 Cummington St.

Boston, MA  02215


Voice: 617-353-6980

Fax: 617-353-6340

Email: [log in to unmask]


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