Table.

Operational modes of triple quadrupole mass spectrometers.

Name	First Quadrupole	Third Quadrupole	Applications
Product scan	Fixed	Scanned	Structural studies, identification of unknowns, confirmation by spectral matching with standard
Precursor scan	Scanned	Fixed	Detection of structurally related analytes that produce a common fragment ion
Neutral loss (or gain) scan	Scanned	Scanned with fixed offset relative to first quadrupole	Detection of structurally related analytes that eliminate (or gain) a common neutral molecule on collision
Multiple reaction monitoring	Fixed	Fixed	High sensitivity detection of a panel of targeted analytes