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Ultivo Autotune Out of Tolerance

Carol_Ultivo

Hi, we have an LC/MS Ultivo G6465B and recently we saw huge signal intensity drop in dMRM mode (NEGATIVE). After this, we obtain Autotune “Out of Tolerance” for several times.
We performed the following processes:
Nebulizer (capillary) cleaning with high flows (5 ml/min) and sonication using various solvents, ion source cleaning, including ion transfer capillary, cleaning and verification of the calibrant delivery system, replacement of the calibrant solution with a new one, replacement of the ion transfer capillary with a new one. None of these processes has resulted in a signal increase in dMRM.
After all of this, it is decided to analyze again the sample in dMRM mode (NEGATIVE) but changing the resolution of the first and second quadrupoles in dMRM method (We always work with a resolution of 'Unit' in both quadrupoles). Different combinations are tested. In summary:
It is observed that changing the resolution from ‘Unit' to ‘Wide' in both quadrupoles increases the signal intensity.
It is observed that further increasing the signal intensity occurs when changing the resolution from Wide' to Widest' in both quadrupoles (good signal values).
The signal stays high (good values)when we set the first quadrupole to 'Widest' and the second one to 'Unit' resolution.
The signal drops significantly when the first quadrupole is set to 'Unit' resolution and the second one to 'Widest’.
I would appreciate any suggestions to be able to PASS Autotune again. Thanks!

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    Hi Carol,

    There is always a trade-off between Scan speed, mass resolution and sensitivity in any quadrupole mass filter. So if you decrease the resolution and keep scan speeds the same you will naturally get an increase in sensitivity. Based on the trouble-shooting you have done already to solve the low tune abundance issue I would suggest raising a service request with Agilent to do some remote t-shooting or if required to come and have a look at the system in detail, as I suspect you may have front end contamination that is causing a reduction in ion transmission to your detector.

    How is the tune sensitivity in positive mode? Is only Negative mode affected, or are you also seeing failing tunes in positive mode as well?

    Looking at the MS1 full scan and MS2 full scan results in positive mode to see what other ions besides tune ions are present would be a good start for any remote diagnostics. If you log a service request with Agilent Assist they can assist in this regard. Negative mode can hide contamination as the contaminants are not ionized in comparison to positive mode. This is why we normally revert back to positive mode for any tune abundance troubleshooting as it is more diagnostic.

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  • 0

    Hi Carol,

    There is always a trade-off between Scan speed, mass resolution and sensitivity in any quadrupole mass filter. So if you decrease the resolution and keep scan speeds the same you will naturally get an increase in sensitivity. Based on the trouble-shooting you have done already to solve the low tune abundance issue I would suggest raising a service request with Agilent to do some remote t-shooting or if required to come and have a look at the system in detail, as I suspect you may have front end contamination that is causing a reduction in ion transmission to your detector.

    How is the tune sensitivity in positive mode? Is only Negative mode affected, or are you also seeing failing tunes in positive mode as well?

    Looking at the MS1 full scan and MS2 full scan results in positive mode to see what other ions besides tune ions are present would be a good start for any remote diagnostics. If you log a service request with Agilent Assist they can assist in this regard. Negative mode can hide contamination as the contaminants are not ionized in comparison to positive mode. This is why we normally revert back to positive mode for any tune abundance troubleshooting as it is more diagnostic.

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