no fragmentation in iontrap

[aldij]

hi,
i am working on the analysis of oxazepam and oxazepam-glucuronide with lc-msms on an iontrap.
when i bring oxazepam in it gives a nice m+1 in ms and i can fragment this to m+1-H2O.
when i bring oxazepam-glucuronide in it gives a nice m+1 but when i try to fragment it i see no fragments. even with the lowest energy (0%) a see no signal, even the M+1 is gone.
i have seen this before even with compounds i read about that other labs can do MSMS on with an triple-quad.
my questions are
has anybody seen this?
is this an iontrap-thing?
is there anyway i can tweak settings to give a MS/MS-spectrum?

i ame working on an LCQ-classic.

thanks i.a. for your input.

[MG]

If the instrument will let you, try an isolation-only experiment (no fragmentation cycle). If you still don't see it, then it is being lost in the isolation step. Either way (either with isolation-only or with frag amplitude set to zero) try to increase your isolation window and see if it comes back. I remember one or two compounds that needed a wider isolation window than default, otherwise they would be lost in the isolation step. I couldn't explain the behavior, though.

[aldij]

whow! that did the trick! it works.
but i can not come up whit a good expalanation.
anybody has any idea why this works?