Triggered MRM LC/MS/MS Method Development — Practical Considerations for MRM Optimization using Agilent MassHunter Optimizer Software

This technical overview provides practical considerations for routine optimization of compounds using MassHunter Optimizer, drawing from our experience of developing a large pesticide multiresidue tMRM LC/MS/MS method.

Optimization of multiple reaction monitoring (MRM) conditions is an essential part of any liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method development.

A typical MRM or dynamic MRM (dMRM) method employs two MS/MS transitions per analyte: one for quantification, and the second one as a qualifier for identification purposes. In a triggered MRM (tMRM) method using Agilent 6400 Series triple quadrupole LC/MS systems, up to 10 MS/MS transitions can be acquired for each analyte, and combined into a product ion spectrum (at optimum collision energies for each product ion), which is used for library matching, and provides increased identification confidence. Using the tMRM function, some of the transitions (primary transitions) are acquired during the entire analyte acquisition window. The acquisition of the additional transitions is triggered (and performed for a defined number of scans) when one of the primary transitions exceeds the set abundance threshold.