Influence of gas modifiers on the TIMS analysis of familiar explosives

Abstract

In the present work, we studied the influence of the bath composition (e.g., organic modifiers) on the mobility resolving power, resolution, and lifetime of familiar explosives during trapped ion mobility spectrometry (TIMS). Experimental results showed the dependence of the mobility with the organic modifiers (mass and size) for the case of TIMS-MS. Different from trends observed in drift tube like IMS devices, no correlation between the mobility resolving power and resolution in TIMS was observed with the bath gas composition (e.g., air, air + methanol, air +2-propanol, and air + acetone). Time decay plots showed that common explosives with adduct complexes signal decrease over time as a function of the trapping time, without any significant improvement with the addition of the organic modifiers. Theoretical calculation of potential clustering and dissociation pathways supported the time decay findings since no major energetic differences between the pathways were observed as a function of the organic modifiers. Our findings suggest that beside the size of the collision partner, there are specific intermolecular dynamics that drive the trapping behavior of familiar explosives.