I have a 6890 GC-ECD with a dual column set up.  I am getting a peak coming up on only one of my columns when i run a blank, and this peak is very close to the retention time of my one analyte.  I did the no injection blank, and the peak still shows on just the one column so it is coming from the instrument and not an outside source.  Can anyone suggest what i should do to try to fix my problem?

  • Hello  ,

    I’m sorry for the delayed reply to your message.  Do you still need assistance with this? If you do, please take into consideration the notes below. However, if the issue was resolved, could you please share what the resolution was? 

    Did you only run one instrument (non-injection) blank? If you did, I would try doing subsequent instrument blanks (let's say 5 blanks) and see if the peak decreases or not.

    If the channels are identical (same inlet type, same column, same injection method), you can also swap the columns and see if the problem follows the column or the inlet/detector).

    Other ways of getting rid of contaminations include performing inlet maintenance (changing consumables in the flow path), changing the syringe if using an ALS injector, performing maintenance on the Headspace injector (changing consumables in the flow path), if applicable. Trimming the column is always a good idea, on both inlet and detector ends.

    Lastly, you can also try baking out the inlet, column and the detector to remove possible contaminants.

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