By scanning the amplitude of the electric field and recording the ions at the detector, one obtains a mass spectrum. Quadrupole MS is capable of resolving mass accuracy of 0.1 to 1 dalton and thus excels in quantitative measurements. Most experiments are performed on triple quadrupole instruments, consisting of three sections: two mass separating quadrupole sections separated by a central quadrupole sections separated by a central quadrupole (or a higher multipole) section, which contains the ions during fragmentation.

Quadrupole MS can sometimes be combined with TOF, so that the dissociated ions enter the TOF analyzer for getting the mass spectrum. For instance in a quadrupole TOF instrument, the first quadrupole (qo) focuses the ions, second quadrupole (q1) separates the ions and the third quadrupole (q2) dissociates the ions to enter the TOF analyser, where the ions are pulse accelerated into the reflector and then to the detector. Qauadrupole TOF analyser may sometimes be used with MALDI ion source as done in MALDI-quadrupole TOF (MALDI-q TOF).