Radio-frequency mass selective excitation and resonant ejection of ions in a three-dimensional quadrupole ion trap

Publisher Website
Google Scholar
Abstract
The three−dimensional quadrupole ion store (QUISTOR) has been employed as a reactor for the study of ion/molecule reactions using external mass analysis, and as an ion trap for the study of stored ion dynamics using either external mass or in situ resonant absorption. Excitation of the axial frequency component of ion motion is accomplished by application of small (∠1 V) RF potentials to an end−cap of the QUISTOR. The frequencies at which ion resonance is observed differ from those predicted by theory and are dependent upon trapped ion density. Thus, the frequency shift may be related to both the space charge within the QUISTOR and perturbation of the stability diagram. the simultaneous application of in situ resonance absorption and external mass analysis has been utilized in three separate studies. (1) In ionized argon, Ar+ has been ejected by resonance absorption and the rate constant for the subsequent partial charge reaction of Ar2+ with argon has been determined to be 4.8±1.6×10−12 cm3 molecule−1s−1. (2) In ionized 2−propanol at ∠0.1 Pa and 4 ms after the ionizing pulse, we have found the ambient space charge experienced simultaneously by nine ion species to be sensibly constant. (3) The coupling of precursor to product ions in ion/molecule reactions of the 2−propanol system has been investigated: this particular application closely resembles the double resonance technique in ion cyclotron resonance mass spectrometry.

This publication has 0 references indexed in Scilit: