Can I see signal from a precursor fragmentation in Skyline from a SIM/MS2 experiment (Orbitrap Elite)?

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Can I see signal from a precursor fragmentation in Skyline from a SIM/MS2 experiment (Orbitrap Elite)? barryh  2016-06-23 12:03
 
Hello there,

Not sure if this is possible, but I was wondering if for an absolute quantitation experiment I could see my fragment ions in addition to the precursor (from SIM). My method contains a SIM event for the peptide of interest and then a fragmentation event using the exact parent mass that Skyline generates, I have imported this data but I can only see the peak for the precursor ion.

Thank you very much,

Hilda HB!
 
 
Brendan MacLean responded:  2016-06-23 13:50
Hi Hilda,
Can you send screenshots of what you are seeing as well as your Transition Settings - Full-Scan tab?

That should help us understand. Thanks.

--Brendan
 
Brian Pratt responded:  2016-06-23 14:12
Hilda,

I think this is related to your request of yesterday, I'll let Brendan know we have the data.

- Brian
 
barryh responded:  2016-06-23 15:02
Brian,

Yes, however, I ran a different method using the mass generated by Skyline and I can see the precursor without having to open up the m/z tolerance but I still do not see the fragments. Here are the the screenshots of my settings and my Orbitrap method.

Thank you very much,

Hilda HB!
 
barryh responded:  2016-06-23 15:03
Other two screenshots
 
Brendan MacLean responded:  2016-06-23 15:13
Hi Hilda,
Unfortunately, you have omitted the most informative screenshot, perhaps to avoid giving away your target peptides.

In the direct email you sent, however, it was clear that the problem is in your targets. You have not targeted anything other than the monoisotopic precursor peak, which makes your Full-Scan settings for MS1 with Peaks Count = 10 a bit strange. You could have more easily used a count of 1 to achieve what you show in your targets.

This means that your transitions must be manually edited already, and automatically calculated from your Transition Settings, or you would be targeting other isotopes of your precursors (e.g. M+1, M+2, M+3, etc.) You now need to manually edit them further to add fragment ion transitions.

I would suggest that you fully review the Targeted MS/MS (PRM) tutorial, as it covers all of this pretty thoroughly:

https://skyline.gs.washington.edu/labkey/wiki/home/software/Skyline/page.view?name=tutorial_prm

Hope this helps. Good luck with your experiment. Thanks for sending the screenshots.

--Brendan
 
barryh responded:  2016-06-24 13:17
Ok, I picked all children, re-imported data, selected product ions on the view option and I can finally see all my fragments. Not sure why it didn't work yesterday. Thank you very much for all the help. I greatly appreciate it.

Hilda HB!
 
Brendan MacLean responded:  2016-06-24 13:20
Hi Hilda,
Great news! Thanks for the update. Good luck with your research.

--Brendan