SharedProteomics

Hi,
I recently got a problem with my Q exective MS, the MS1 signal suddenly droped from 10E9 to 10E7, although background signal also droped, and the spectra looks normal too. The MS2 looked good too with 10E7 signal. I searched the data, and still gives me lots of proteins IDs. I switched from nanospray to regular HESI sourse, and the signal is still low. Does anyone here have a clue about this problem?
thank you!

SunSun

Do you normally clean your ion transfer tube? If it is dirty and starting to clog, you will experience a drop of signal. Otherwise it could be dirty front optics even if your endurance test is giving good results.

Easier thing to test would be replacing the used tube for a new one and see what happens.

Hi,

I would also check the and clean the S-lens behind the transfer tube.