multiple reaction monitoring
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multiple reaction monitoringA multistage/mass spectrometry (MS/MS) experiment that uses two sequential stages of independent mass analysis. In the product ion MS/MS scan, a precursor ion is selected by mass with the first mass analyser, and the fragment ions formed by collision-induced dissociation are measured with a scan of the second mass analyser and recorded in a mass spectrum.
In an analogy to selected ion monitoring, if both mass analysers in an MS/MS instrument are set on a specific mass, the signal represents the precursor-to-product ion transition for a specific ion pair and is termed reaction monitoring. If several different precursor–product ion pairs are monitored, as is the norm, the analysis is termed multiple reaction monitoring.