Analysis acetic acid and formic acid GC-MS

Hi,

I am trying to create a GC-MS method for the headspace analysis of solid material. I will sample the headspace of this solid material with a SPME CAR/PDMS fiber. Some of the components in the headspace are acetic acid and formic acid, but I run into some problems while creating the method for this two components.  We only want to qualify the components, quantifying the components is not necessary. We are using a HP-5 column (30m) and we prefer to analyze using this column. Here are some details from the method I use:

Injection: splitless with SPME with a injection temperature of 220 C
Oven program: 30 C with a hold time of 2 minutes; then a ramp of 20 C/min to 220 C with a hold time of 10 minutes

Many thanks!

  • Then you to do method optimization as a try to get optimum result, like flow change, oven temp change, split ration change etc etc...

  • I'm still struggling as well with headspace SPME injection. I have a lot to learn and so little time...

    To understand even further, do you have an automatic injector? Do you sample automatically? I'm saying that because I use a PAL autosampler with a little oven for HS-SPME extraction and injection.

    So, from what I could understand, you might be overloading your column. Try to reduce the extraction time with the SPME and/or the extraction temperature. You can try to reduce the injection time as well (regenerate fiber after that). Reducing the ramp can help the separation of compounds. Eventually, because I have been told it can be done but I'm not convinced, you could use a split injection with a splitless liner (not the opposite) to reduce even further the amount of material injected.

    Finally, during data analysis, you can:

    • extract typical ions for formic and acetic acids from the chromatogram and visually assess if you have those compounds,
    • or try to use AMDIS (I have the feeling it can very useful but I lack time to understand it properly).

    Good luck

  • Excuse me for my late response. I took a few days off.

    Haha me too! I still have a lot to learn and too little budget and time to gain enough information....

    No, we don't have an automatic injector. We do our injections manually. Thanks for the tips! I didn't know AMDIS. I will use the tips in the method development. Good luck with your research and method development :) 

  • Hi I moved your question from the Gas Chromatography group to the GC/MS group for better visibility.  I see there was a lot of discussion here, were you able to come up with a solution to your problem?

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