Title | | » | Small molecules: need negative ion capability |
Assigned To | | » | bspratt |
Type | | » | Defect |
Area | | » | Skyline |
Priority | | » | 3 |
Milestone | | » | 3.1 |
One thing that caught my eye is the current setting of everything to positive charge (ESI+). I tried to set a precursor to charge of -1 in the import/transition list table, thinking it would be all too simple if that was the ‘trigger’ for an ESI- method. I can’t remember if we have talked about this before or not, but the main thing Skyline would need to do is to simply annotate an ion as negatively charged, adjust the M-H calculation accordingly, and set the mass spectrometer mode to ESI- in the method file for those particular analytes. Waters and many other TQ instruments allow ESI+ and ESI- ions in the same method, thus performing ‘polarity switching’ as part of the SRM method.
We are building methods right now for fatty acids (Omega 3 and Omega 6) and downstream metabolites, so that is why ESI- just happens to be high on my list right now.
Cheers
Will
J. Will Thompson, Ph.D.