Chromatography

MRM

MRM stands for Multiple Reaction Monitoring. In MRM, a specific ion (precursor ion) is selected in Q1 (first stage MS) from among various ions ionized by the ionization probe, the ion is destructed (collision-induced dissociation) in the collision cell (Q2, collision chamber), and a specific ion is detected from among the destructed ions (product ions) in Q3 (second stage MS). Multiple channels can be set in one measurement. In the LCMS-8030, a maximum of 512 events x 32 channels can be set per analysis.
* MRM is also called SRM (Selected Reaction Monitoring).

In analyses with a significant amount of potential interferences, such as analysis of pesticides in foods, LCMS is sometimes inadequate because high background levels are observed. In LCMSMS, analysis can be performed with no Interference from background ions because of the selectivity resulting from two stages of mass isolation.

In LCMSMS (MRM), the ion intensity of the analyte peak is lower as compared to LCMS (SIM). However, LCMSMS provides higher sensitivity analysis than LCMS because the signal to noise ratio (S/N) is improved due to significantly lower noise levels.