Kinetics of isobaric ion/molecule reactions determined by the flowing afterglow‐triple quadrupole technique

An experimental method is described for determining the kinetics of gas‐phase ion/molecule reactions involving reactant and product ions with the same nominal or exact masses (i.e., isobaric ion/molecule reactions) using a flowing afterglow‐triple qvadrupole instrument. The method involves formation of specific monitor ions in the triple quadrupole analyzer by collision‐induced dissociation, exothermic ion/molecule reactions or energy‐resolved ion/molecule reactions for use in determining the kinetics of reaction of one component of an isobaric ion mixture in the flow tube. The measured depletion of these types of monitor ions is shown to provide a reliable means of determining the rate coefficient for the overall reaction taking place when a neutral reagent is added to the flow reactor.