A Kinetic Analysis of Collision Experiments in Triple Quadrupole Instruments. Validation of the Kinetic Method

Abstract

A kinetic analysis of collisionally induced decompositions in a triple quadrupole mass spectrometer is described. The analysis is used to calculate reaction probabilities for the decomposition of proton-bound dimers of amines. A modified form of the simple QET expression is used for the rate constants. With this expression for the rate constant, model calculations show that the reaction probabilities for competing fragmentation reactions depend only slightly on where during passage of the collision region the parent ion is activated, and hardly at all on the velocity of the activated ion through the collision region. This simplifies the calculations of relative ion abundances. The analysis is subsequently used to calculate the relative fragment ion abundances from decomposition of proton-bound amine dimers and this leads to a validation of the kinetic method.