10 fold peak hight in negative ion mode

[milo83]

Hi

I ran a autotune today. Usually I only tune for positive ions. But this time I inlcluded negative ions. I noticed that the intensities of the negative peaks was 10-fold the positive ones. I used the Agilent ESI low concentration tuning mix for tuning with default settings. The instrument I use is Agilent 6420 QQQ.

Is this normal?

[Pepter]

Hello,
Our 6460 and 6410 behaves similarly. Depends on m/z it give up to 10-fold or even more higher signal than in positive mode.
Maybe check some older tune reports for negative or even the first one (service verification during installation).