KINETICS OF ISOBARIC ION-MOLECULE REACTIONS DETERMINED BY THE FLOWINGAFTERGLOW-TRIPLE QUADRUPOLE TECHNIQUE

An experimental method is described for determining the kinetics of ga s-phase ion/molecule reactions involving reactant and product ions wit h the same nominal or exact masses (i.e., isobaric ion/molecule reacti ons) using a flowing afterglow-triple quadrupole instrument. The metho d involves formation of specific monitor ions in the triple quadrupole analyzer by collision-induced dissociation, exothermic ion/molecule r eactions or energy-resolved ion/molecule reactions for use in determin ing the kinetics of reaction of one component of an isobaric ion mixtu re in the flow tube. The measured depletion of these types of monitor ions is shown to provide a reliable means of determining the rate coef ficient for the overall reaction taking place when a neutral reagent i s added to the flow reactor.