5977 Noisy 502 m/z peak and a pw50 of 0.28 after Etune

After running an Etune on our instrument we noticed noisy and asymmetric peak for 502 m/z. Additionally, the corresponding PW50 is 0.28. However, the Atune report looks fine. I understand Etune uses more components of the source but I don't understand why the tunes look vastly different. I have attached both Etune, and Atune reports. Any input would be appreciated.



  • At 310° C ion source temperature, the 502 will always be lower than typical.  Also - please reduce the quad temperature down to 150° or maybe as high as 165° C... High quad temperature reduces the lifetime of the quad and only very few applications need it.   310°C in a vacuum is equivalent to 700°C and 190° C is equivalent to 500°C at atmospheric pressure.

    The 502 is low from the temperature and possibly cleanliness, too, and so when Etune tries to use the ion body and extractor lenses to work its magic, it struggles, either with low throughput of 502 or increased 69. The fact that the EM is up 373 volts is also an indication of this struggle.

    If Atune looks typical and Etune doesn't, replace the extractor lens insulator and the transferline tipseal ceramic first.  They are part of the ionization chamber and get contaminated with sample. They cannot be effectively cleaned.  The adhered organic layer conducts and then the ion body and extractor lens are not working properly, leading to strange tuning.  That insulator, the repeller side repeller insulator, and the transferline tipseal ceramic must be replaced quite frequently due to their location.  The 10.00V Ion Body and 4.98V Repeller voltages are both max, which may indicate this as the problem.

    Next is to make sure that the brown extractor lens wire is not pinched or crimped between the source/analyzer and the transferline when the system is closed for pumpdown.  That brown wire needs to be replaced when crimped and once in a very long while if handled properly.

    The last thing to check is that the transferline tip seal is installed properly on the transferline. If the tipseal base is not seated correctly, it can touch the edge of the repeller heater/sensor block which shorts the ion body voltage to ground. That would mean that the ion body's electromagnetic field is not functioning properly and Etune won't work right.

    The high vacuum gauge is broken and should be replaced.

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