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Octane on GC-IRMS with DB5 Column?

Posted: Fri Apr 13, 2018 1:01 pm
by allie06
I am trying to analyze octane by GCIRMS but instead of one octane peak I am getting several small peaks. I have tried adjusting the inlet temperature ranging from 250 to 150 and my current temperature program is 40C increased to 100C at 4C/min. Does anyone have any successful octane methods?

Re: Octane on GC-IRMS with DB5 Column?

Posted: Fri Apr 13, 2018 2:39 pm
by rb6banjo
Just pure octane? Octane in something else? Seems odd. Octane (pure solvent) should be like a model system.

Can you inject any other pure solvent and see a single peak? What are your scan parameters in the MS part of your method? Make sure you're at least scanning up from 50. I mostly do volatiles by SPME in a high-ethanol matrix (MW = 46 g/mole) so I generally go 50-350 when I'm operating in scanning mode. You can go wider or more narrow depending on your application.