Please help: Weird peak of separation of 5 amphetamine drugs

[fuh123]

I'm using a previous established LC-MS/MS method for detection of 5 amphetamine drugs. AB Sciex QTrap 5500 with Shimazdu LC.
Mobile Phase A 0.1% Fomic Acid in H2O Mobile Phase B ACN.

I got weird peak as shown in the pic. The 1st peak (red one) is amphetamine, which was really broad. I was wondering if something wrong with the column? I don't think MS part wrong. So might be the LC part problem. Do I need to flush the column more often?

https://drive.google.com/file/d/0B7AR3a ... sp=sharing



New to LC-MS world. Please make your comments. Thanks!

[tom jupille]

My first guess would be a gross overload. Easy to check:dilute 1/10 and reinject.

[carlo.annaratone]

I would say overload as well

[fuh123]

Thanks for the reply!

Updates: It was not an overloading issue. Turned out the column related. By switching to a new column, peaks were perfect. And ACN was not a good mobile phase. MeOH is better for amphetamine type compounds. Just FYI.

[tom jupille]

Thanks for the update!