QQQ6410B sensitivity

[remaou]

Hi, I'm using an Agilent QQQ ESI-6410B and the sensitivity is decreasing more and more, even after source-capillary-skimmer cleaning. From last year and for all the compounds the responses have been divided by 4 ! and more again from the installation...
I've seen a video showing how to clean the High Energy Dynode. Has someone already done that ? Is it a "normal" maintenance and do you think it could improve again the sensitivity ? Or do you have other ideas to solve my problem ?
Thanks for your answer.

[Pepter]

Hi iam also user of ESI-6410.
How about your tune reports (the same change "x4" in ion abundance from first tune/checktune and the last one ?).
Did you inspect your nebulizer needle tip ?