title: Ion collision crosssection measurements in quadrupole ion traps using a time-frequency analysis method.
abstract: In this study, a method for measuring ion collision crosssections (CCSs) was proposed through time-frequency analysis of ion trajectories in quadrupole ion traps. A linear ion trap with added high-order electric fields was designed and simulated. With the presence of high-order electric fields and ion-neutral collisions, ion secular motion frequency within the quadrupole ion trap will be a function of ion motion amplitude, thus a function of time and ion CCS. A direct relationship was then established between ion CCS and ion motion frequency with respect to time, which could be obtained through time-frequency analysis of ion trajectories (or ion motion induced image currents). To confirm the proposed theory, realistic ion trajectory simulations were performed, where the CCSs of bradykinin, angiotensin I and II, and ubiquitin ions were calculated from simulated ion trajectories. As an example, differentiation of isomeric ubiquitin ions was also demonstrated in the simulations.
authors.affiliation: School of Life Sciences, Beijing Institute of Technology, Beijing 100081, China. weixu@bit.edu.cn.
authors.forename: Muyi
authors.initials: M
authors.lastname: He
authors.forename: Dan
authors.initials: D
authors.lastname: Guo
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: Xingchuang
authors.initials: X
authors.lastname: Xiong
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
mesh_terms: D000803:Angiotensin I / Q000737:chemistry*; D000804:Angiotensin II / Q000737:chemistry*; D001920:Bradykinin / Q000737:chemistry*; D003198:Computer Simulation; D005583:Fourier Analysis; D013058:Mass Spectrometry / Q000379:methods; D008962:Models, Theoretical; D025801:Ubiquitin / Q000737:chemistry*
chemical_list: D025801:Ubiquitin; D000804:Angiotensin II; D000803:Angiotensin I; D001920:Bradykinin