Retention Time Locking between methods

Hi everyone,

Following Agilent instructions, I did the Retention Time Locking using the MassHunter GC/MS Acquisiton Software for one of our methods. In case I want to have the retention time locked in another method, should I do again all the process (doing again the five runs, etc.) or there is an easy way to import my RTL from the first method to the second one?



  • You should typically do a full lock on all new methods, or build new method from RTL locked method.

  • Thanks for the answer. Just one more thing, how does the Relock work? Once you have the RTL locked in your method but your RT have moved, do you need to do the five runs again?

  • Make run one, Open MSD Chemstation Data Analysis, load the data file, then under Tools...RT Lock Setup.

  • To relock a method
    You may need to relock the method if:
     The column has been changed or trimmed
     The method is installed on a new instrument
     A detector of different outlet pressure is used
     System performance is validated
     Troubleshooting chromatographic problems
    1. From Instrument Control, run a sample containing the lock compound using the locked method.
    2. Check the retention time of the locked compound. If the compound is eluting at the correct retention
    time, no further action is required. If the compound is NOT eluting at the correct retention time, go to
    step 3.
    3. From Data Analysis, select RTLock Setup.
    4. Select RTLock / Relock Method.
    5. The Relock Method menu item will prompt you to select a data file and peak, perform a cross-correlation
    of the spectrum (MS only; below 0.8 is not allowed), and calculate a suggested pressure based on the
    retention time of the peak in the selected file, the pressure it was collected with, and the curve stored in
    the method. After selecting a peak for locking from the list box, an input box lets you confirm or change
    the retention time in the relock data file.
    6. You will be prompted to update the method with the new pressure.
    Whenever a locked method is loaded into Instrument Control, the title bar will indicate that the method is
    locked, and which compound was used for the lock. The pressure (online instruments only) will be set to
    the locked pressure. If you save a locked method with a new name from Instrument Control, you will be
    asked if the locked status is to be preserved with the new method.
    Note When a locked method is run, the pressure is restored to the locked pressure value EVEN if you have
    made changes using the GC keypad or from Instrument Control.

  • Thanks a lot for the explanation! I'll try it as soon as I can :)

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