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GC-FID split peak issue
Discussions about GC and other "gas phase" separation techniques.
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This is my first time using a GC-FID and i am trying to understand the difference between a good and bad peak. I ran an unknown sample on a DB-5 column at a program ramp condition set at 50c for 1 min, followed by 20c/min to 200c and hold for 2 minutes. I obtained peaks that were split and had retention times that were not similar to the ones I obtained for my reference samples (the unknown consists of any or a mixture of the 10 reference samples). How can I troubleshoot this problem?
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Hi
Welcome to the forum
By giving more detailed information of your sample, reference, conditions and example chromatograms
The more you tell us the more we can help
Welcome to the forum
How can I troubleshoot this problem?
By giving more detailed information of your sample, reference, conditions and example chromatograms
The more you tell us the more we can help
Regards
Ralph
Ralph
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- Location: Sz-n
Split peaks ? Did you inject your samples manually ?
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Are they truly slit, or two unresolved compounds? The only to find out with 2 dimension chromatography is to inject single component standards to check the RT's.
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My sample is an unknown that may consist of any of 10 references (ranging from polar to non-polar). I have already run the references separately and have obtained retention times for them in a nonpolar column at an isothermal temp of 60c. Those peaks were not split. It was a manual injection. The retention times were well resolved for all the references even when I ran them all on the same column but with a temperature programmed ramp and the peaks were not split either. But, when I ran my unknown on the same column (both isothermal and temp ramp), i got split peaks. How would i know if it is an injection technique problem versus something else? ( I did repeat the injection the same day and had the same problem).
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