5973 Autotune

We have been observing split peaks in our 5973 autotunes. The splitting is not consistent as it moves among the main masses (69, 219 and 502). We have cleaned and replaced just about everything to no avail. Has anyone observed the same phenomenon? How was it resolved? Thanks.



  • Hi Bill,


    Has this only just started occurring? Or has it been occurring for a long time or a gradual thing?


    So from my understanding you have cleaned the source/replaced the source, is the DC polarity correct? (on side of MS chamber door (see below). Also what is the flow rate of gas into the MS? do you have the vacuum parameters?

  • The observed splitting appeared suddenly; there were no shoulders that evolved into these splits.  The source has been cleaned, the helium flow rate is 0.8 mL/min and the polarity is set correctly.  Vacuum gauge reads 2.5x10-5 torr


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  • You can try loading an older tune. Sometimes the tunes can get out of touch. So on tune and vacuum control then Restore Previous tune. The look for one from a few months ago.Tune again with the old tune and hopefully it may resolve your issue.

  • Attempts at reverting to previous tunes has not helped.


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  • Can you try switching from filament 2 to filament 1?

    Another avenue to try is that the MS chamber may have a slight residue inside. If you have any lint free cloths (not kimwipes as these are not completely lint free) and use them to just wipe the MS chamber bottom. Make sure not to touch any part with bare skin.

  • We have performed all of the troubleshooting and have had Agilent service in as well.  They say nothing tis wrong.



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  • Hi,

    It is nothing wrong with the instrument. The little split peak doesnt effect your analysis. When the instrument is converting the profile spectra to centroid, the split is ignored. Only if you have very severe split peak (down at 70-60% of the height of the peak) will be the sign of a real problem on your quadrupole or electronic.

    The small splitting on the peak of the ion is due to the value of the repeller (at a high value or his maximum). That indicate a dirty repeller or the ceramics of the repeller polluted by your matrix over the time.

    clean the repeller and change the ceramics will lower the repeller value and the splitting will disappear.

    But in your case the ions seems to be ok. it is not, by far, a dramatic splitting that will affect your analysis.

    I hope that this answer will help.

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