A ship-lock-type reactor for ion-molecule reactions of mass-selected ions under high-pressure conditions

A ship-lock-type reactor has been developed to study ion-molecule reactions of mass-selected ions under high-pressure conditions. Neutral gas molecules can be confined in the reactor by controlling two electromagnet valves to close both the inlet and the outlet of the reactor. Gas-phase ions can be trapped in an ion funnel trap installed in the reactor and interacted with a high-pressure (up to 1000 Pa) reactant gas for a period of time (up to 1 s). The reactions of mass-selected V₂O₆ ^- with CH₄ and n-C₄H₁₀ and mass-selected Au⁺ with n-C₇H₁₆ were investigated to evaluate the performance of the reactor. The hydrogen atom abstraction product V₂O₆H^- was observed for the reaction of V₂O₆ ^- with CH₄, the rate constant was measured to be (1.9 ± 0.4) × 10^-16 cm³ molecule^-1 s^-1, and the kinetic isotope effect value was determined to be 5.4 ± 1.1. Furthermore, the detection limit of n-C₇H₁₆ with 1-min measurements was determined to be (19 ± 2) pptv, which is significantly lower than those in previous studies. These results indicate that the current apparatus is a prospective for the study of slow ion-molecule reactions and the detection of trace amounts of gas species, such as volatile organic compounds.