Prospects for the use of security air flow to prevent ion-molecule reactions in the ionization and drift zone in classical IMS

The effective transfer of sample problem is relevant in modern analytical equipment. The paper considered a problem in detection trace concentrations of explosives by Ion Mobility Spectrometry (IMS). The investigation deals with sample adsorption on the walls of transport tubes, the ion drift chamber and the chamber of the ion source in ion mobility spectrometer. The sample losses on inlet channel surface and diffusion through penetrable gas channels are comparable with the quantity of sample itself at the sensitivity level of 10-14 g / cm3. The trinitrotoluene (TNT) sorption in different channel materials depending on their sorption properties is analyzed. A new approach preventing sorption of the substance on the chamber walls by security airflow is presented. The study includes gas flow simulation and experiments of protective gas flow setup.