Quantifier and Qualifier Transitions
Definition
The most intense MRM transition is the quantifier and is used for the concentration calculation. The second (and sometimes third) transition is the qualifier and confirms identity. The ratio of quantifier to qualifier intensity in the sample must match the same ratio in a reference standard within plus or minus 20 to 30 percent.
Related terms
- Accurate Mass and Mass Defect
- On a Q-TOF or Orbitrap, the measured m/z is reported to four decimal places at parts-per-million accuracy. The deviation from the nominal...
- CID and HCD
- Collision-induced dissociation. The precursor is accelerated and collides with a neutral gas (nitrogen, argon, helium) in the collision cell. Internal energy converts...
- Deuterated Internal Standard
- An isotopologue of the analyte where two to five hydrogens are replaced by deuterium. Same chromatographic and ionisation behaviour, slightly higher mass....
- MRM (Multiple Reaction Monitoring)
- A targeted MS/MS scan mode on a triple quadrupole that monitors specific precursor-to-product ion transitions, with two transitions per analyte (quantifier and...
- Tandem MS (MS/MS)
- Two stages of mass selection in series with a fragmentation step in between. The first stage selects a precursor ion, a collision...
Explained in
- Tandem Mass Spectrometry (MS/MS) and Spectral InterpretationThe most intense MRM transition is the quantifier and is used for the concentration calculation. The second (and sometimes third) transition is the qualifier a...