title: Linear ion trap with added octopole field component: the property and method.
abstract: It is well known that superimposition of some positive octopole field will benefit the performance of ion trap mass analyzer. In the radial-ejection linear ion trap (LIT), adding some octopole field component to the main quadrupole field is usually accomplished by stretching the ejection rod pair. In this study, the effect of octopole potential and some other higher order potential on the performance of LIT mass analyzer is investigated. A simple and effective method, which is to add some octopole component by building a LIT with a pair of rectangular electrodes and a pair of semi-circular electrodes, is reported. Its properties were studied by numerical simulations and experiments. The results showed that a certain amount of positive octopole component could be produced by simply adjusting the position and width of the rectangular electrodes. A resolution of over 1200 at m/z 609 (~1600 Da/s) was observed in this type of LIT. They also performed tandem mass spectrometry well. The device with optimum geometry for ion ejection from rectangular electrodes provided comparable performance to that for ion ejection from semi-circular electrodes. This type of LIT design is easy for fabrication and assembly.
authors.affiliation: Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai, 200433, China.
authors.forename: Qiankun
authors.initials: Q
authors.lastname: Dang
authors.affiliation: Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai, 200433, China.
authors.forename: Fuxing
authors.initials: F
authors.lastname: Xu
authors.affiliation: Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210046, China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Huang
authors.affiliation: National Institute of Metrology, Beijing, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
authors.affiliation: Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai, 200433, China.
authors.forename: Rizhi
authors.initials: R
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai, 200433, China.
authors.forename: Chuan-Fan
authors.initials: CF
authors.lastname: Ding
mesh_terms: D003198:Computer Simulation; D004566:Electrodes; D004867:Equipment Design; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*; D012110:Reserpine
chemical_list: D012110:Reserpine
keywords: linear ion trap; octopole; radial ejection; rectangular electrode; semi-circular electrode