Dear Scientists,
I am new to MS and I am working in PE SCIEX API 3000 LC/MS/MS system.

I have read about the "metastable ion" in some of the text book. Is the metastable ion produce in LCMS?

could anyone give an explanation of metastable ion in LC/MS/MS. What is the role of it in structure prediction. How can confirm the formation of metastable ion in LC/MS/MS. Any literature of reference is available for this in structural characterisation.


Thanks in advance

Dear anonymous,

metastable ion refers to ions that undergo fragmentation before or after the collision cell. In your case (with a MS/MS) system), the degradation occurs probably in the first quadrupole or in the time of flight detector(assuming you use a QTOF system). The major problem with metastable ion is that they produce very large mass peak in a spectrum so they are quite difficult to analyze.

To confirm the presence of a metastable ion I usually look for a very large peak (very hard to miss). As to how you can characterize these ions, the simplest solution is to use a completely different system and hope that different results are obtained.

Hope it helps.

Anonymous January 6: When you say that a large peak is observed, do you mean that the peak is unusually wide, or unusually intense? Thanks for the helpful info.