Influence of ion-molecular reactions on a resolving power of ion mobility spectrometer with Bradbury-Nielsen gate

In order to reveal factors that could significantly affect the resolving power of the ion mobility spectrometer with Bradbury-Nielsen gate, the influence of ion-molecular reactions on the shape of ion peaks and their position is considered. Simulations of the formation of ion pulses by the Bradbury-Nielsen gate and their drift were performed taking into account the ion formation and dissociation reactions. It was shown that transmission properties of the gate being selective, the ions newly formed in the course of the reactions and having lower values of the ion mobility give a significantly wider pulse of small amplitude at the gate exit. Depending on the reaction rates the peaks of the interacting ions coincide at the high rates and at the much slower rates there is an intermediate signal that appear between the ion peaks to be separated. In the case of the water clusters formation and dissociation reactions, the ion peak consist of the several ion components and, depending on the water concentration, its position is shifted toward the position of the cluster of the prevailed size.