Quick Tune vs Autotune

When I run a Quick Tune, the abundances for mass 69, 219, 502 are half compare to Autotune. What is the reason? Do I need to run a calibration after every Quick Tune because the Quick Tune will save the tune parameters to atune file. 

  • From MassHunter Acquisition Help:

    QuickTune provides a fine tuning to ensure acceptable response and resolution and accurate mass assignment. Only the mass axis, peak widths, and EM voltage are adjusted; the lenses are unaffected.

    It does not adjust the relative abundances of the three tuning masses. As long as these relative abundances are at acceptable values (in other words, the instrument is already nearly tuned), QuickTune is the preferred method of daily tuning.

    If your acquisition method is set to run the EMV in GAIN mode, the gain curve should be nearly the same as it was and the system will adjust for any differences in the EMV.  You could also run QuickTune and then manually change the tune file EMV to the value it was before the QuickTune and save it.  Or, you could manually run the mass axis and peak width portions of the autotune and save the tune file.

    The tune on most clean operating MSDs is amazingly stable. Every full tune can adjust every parameter so the tune values may look different but that's because the algorithm always adjusts them.  It could be that all you need to do is to do File, Generate Report.  This turns on the PFTBA and give a report using the loaded tune file parameters but gets new data - new tune ion peaks and the spectrum.  You must manually look at it to know if it's acceptable before using it.

    Also, the amount of time the PFTBA valve is on will change the abundances.  It starts higher and tapers off over time before stabilizing as the vacuum equalizes between the chamber and the PFTBA vial through the very small restrictor inside the PFTBA valve.  After the valve turns off, that pressure will re-equilibrate over time and the process starts again. 

    The lab temperature also affects the PFTBA abundance. This is a headspace analysis of the PFTBA vial, so changes in temperature change the headspace concentration.

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