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Xu F, Wang W, Jin L, Qian B, Ding CF. Measurement of the effective electric field radius on digital ion trap spectrometer. Analyst 2021; 146:3810-3817. [PMID: 33977965 DOI: 10.1039/d1an00468a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effective electric field radius is a fundamental parameter of ion traps, and it has a significant influence on ion-trapping capability, signal intensity, mass range and some other properties of the ion trap. For a quadrupole ion trap built with ideal hyperbolic electrodes, its effective electric field radius can be obtained by its geometrical size, while it is very difficult to obtain the effective electric field radius for a non-hyperbolic ion trap. In this study, the effective electric field radius of a linear ion trap and some ceramic rectilinear ion traps (cRITs) were investigated via the digital ion trap technology. The dipole frequency of supplementary AC for excitation was locked at a certain value of the main RF trapping wave, and the characteristic q values for excitation could be determined accordingly. The q values could be further used to calculate the effective electric field radius through theoretical calculations. A linear equation had been fitted between the q values for excitation and the square of period T2 through experiments subsequently. The relative deviation between the measured electric field radius and the simulative electric field radius is less than 2%. The simulation results and experimental validation show that the approach has predictive power for modeling and measuring the effective field radius of non-hyperbolic ion traps. It is certainly significant for further understanding the performances of non-hyperbolic quadrupole systems.
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Affiliation(s)
- Fuxing Xu
- Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis of Zhejiang Province, Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Weimin Wang
- Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis of Zhejiang Province, Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Liuyu Jin
- Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis of Zhejiang Province, Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Bingjun Qian
- Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis of Zhejiang Province, Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Chuan-Fan Ding
- Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis of Zhejiang Province, Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
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Tesler LF, Cismesia AP, Bell MR, Bailey LS, Polfer NC. Operation and Performance of a Mass-Selective Cryogenic Linear Ion Trap. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2115-2124. [PMID: 30062479 PMCID: PMC6301008 DOI: 10.1007/s13361-018-2026-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/26/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
We report on the performance of a cryogenic 2D linear ion trap (cryoLIT) that is shown to be mass-selective in the temperature range of 17-295 K. As the cryoLIT is cooled, the ejection voltages during the mass instability scan decrease, which results in an effective mass shift to lower m/z relative to room temperature. This is attributed to a decrease in trap radius caused by thermal contraction. Additionally, the cryoLIT generates reproducible mass spectra from day-to-day, and is capable of performing stored waveform inverse Fourier transform (SWIFT) mass isolation of fragile N2-tagged ions for the purpose of background-free infrared dissociation spectroscopy. Graphical Abstract ᅟ.
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Affiliation(s)
- Larry F Tesler
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
| | - Adam P Cismesia
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
| | - Matthew R Bell
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
| | - Laura S Bailey
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
| | - Nicolas C Polfer
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA.
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Rajagopal V, Stokes C, Ferzoco A. A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:260-269. [PMID: 28822082 DOI: 10.1007/s13361-017-1763-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 107 detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes. Graphical Abstract ᅟ.
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Affiliation(s)
| | - Chris Stokes
- The Rowland Institute at Harvard University, Cambridge, MA, 02142, USA
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Cismesia AP, Tesler LF, Bell MR, Bailey LS, Polfer NC. Infrared ion spectroscopy inside a mass-selective cryogenic 2D linear ion trap. JOURNAL OF MASS SPECTROMETRY : JMS 2017; 52:720-727. [PMID: 28750482 PMCID: PMC5690808 DOI: 10.1002/jms.3975] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate operation of the first cryogenic 2D linear ion trap (LIT) with mass-selective capabilities. This trap presents a number of advantages for infrared ion "action" spectroscopy studies, particularly those employing the "tagging/messenger" spectroscopy approach. The high trapping efficiencies, trapping capacities, and low detection limits make 2D LITs a highly suitable choice for low-concentration analytes from scarce biological samples. In our trap, ions can be cooled down to cryogenic temperatures to achieve higher-resolution infrared spectra, and individual ions can be mass selected prior to irradiation for a background-free photodissociation scheme. Conveniently, multiple tagged analyte ions can be mass isolated and efficiently irradiated in the same experiment, allowing their infrared spectra to be recorded in parallel. This multiplexed approach is critical in terms of increasing the duty cycle of infrared ion spectroscopy, which is currently a key weakness of the technique. The compact design of this instrument, coupled with powerful mass selection capabilities, set the stage for making cryogenic infrared ion spectroscopy viable as a bioanalytical tool in small molecule identification.
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Affiliation(s)
| | | | | | | | - Nicolas C. Polfer
- Correspondence to Nicolas C. Polfer, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32611-7200, USA.
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Xu F, Konenkov NV, Ding H, Wang Y, Ding CF. Linear ion trap mass selectivity with impulse power supply and sinusoidal dipolar excitation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:2664-2670. [PMID: 27528382 DOI: 10.1002/rcm.7721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE An ion trap mass analyzer can be operated by either a sinusoidal waveform power supply or an impulse waveform power supply. The optimal conditions for the performance of ion trap which is driven by an impulse waveform power supply with sinusoidal dipolar voltage were investigated theoretically, and further verified by experiments. METHODS The analytical relationship between β and q values is derived theoretically for optimal performance, and the dependencies β(q) for different trapezoidal waveforms are studied. To explain the dependence of resolution with working point q, the derivative dβ/dq is also derived analytically for the case of a rectangular waveform power supply. The theoretical results are further verified by experiments. RESULTS The results from both theoretical calculations and experiments are in very good agreement. The behaviour resolution with q is controlled by the dispersion dβ/dq that was also confirmed by experiments, when the resolution increases with q. CONCLUSIONS The optimal conditions of β, qex values and required excitation time n are when S(q) is close to 1 for an ion trap driven by trapezoidal waveform voltage with sinusoidal dipolar voltage. It shown that with increasing impulse parameter τ the dispersion dβ/dq decreases and the mass resolution also decreases as result. In the case of applying a rectangular waveform shape voltage, the mass selectivity is the same as for the sinusoidal wave shape. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Fuxing Xu
- Department of Electronic Engineering, Fudan University, Shanghai, 200433, China
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry and Laser Chemistry Institute, Fudan University, 220 Handan Road, Shanghai, China
| | - Nikolai V Konenkov
- Physical and Mathematical Department, Ryazan State University, Ryazan, Svoboda 46, 390000, Russian Federation
| | - Hangyu Ding
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry and Laser Chemistry Institute, Fudan University, 220 Handan Road, Shanghai, China
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai, 200433, China
| | - Chuan-Fan Ding
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry and Laser Chemistry Institute, Fudan University, 220 Handan Road, Shanghai, China
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Affiliation(s)
- Qinghao Wu
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Ailin Li
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Yuan Tian
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Richard N. Zare
- Department
of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Daniel E. Austin
- Department
of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
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Affiliation(s)
- Dalton T. Snyder
- Department of Chemistry and Center for Analytical Instrumentation
Development, Purdue University, W. Lafayette, IN 47907
| | - Christopher J. Pulliam
- Department of Chemistry and Center for Analytical Instrumentation
Development, Purdue University, W. Lafayette, IN 47907
| | - Zheng Ouyang
- Weldon School of Biomedical Engineering, Purdue University, W.
Lafayette, IN 47907
| | - R. Graham Cooks
- Department of Chemistry and Center for Analytical Instrumentation
Development, Purdue University, W. Lafayette, IN 47907
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Dang Q, Xu F, Xie X, Xu C, Dai X, Fang X, Ding L, Ding CF. Enhancement of Ion Activation and Collision-Induced Dissociation by Simultaneous Dipolar Excitation of Ions in x- and y-Directions in a Linear Ion Trap. Anal Chem 2015; 87:5561-7. [PMID: 25919746 DOI: 10.1021/acs.analchem.5b00118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Collision-induced dissociation (CID) in linear ion traps is usually performed by applying a dipolar alternating current (AC) signal to one pair of electrodes, which results in ion excitation mainly in one direction. In this paper, we report simulation and experimental studies of the ion excitation in two coordinate directions by applying identical dipolar AC signals to two pairs of electrodes simultaneously. Theoretical analysis and simulation results demonstrate that the ion kinetic energy is higher than that using the conventional CID method. Experimental results show that more activation energy (as determined by the intensity ratio of the a4/b4 fragments from the CID of protonated leucine enkephalin) can be deposited into parent ions in this method. The dissociation rate constant in this method was about 3.8 times higher than that in the conventional method under the same experimental condition, at the Mathieu parameter qu (where u = x, y) value of 0.25. The ion fragmentation efficiency is also significantly improved. Compared with the conventional method, the smaller qu value can be used in this method to obtain the same internal energy deposited into ions. Consequently, the "low mass cut-off" is redeemed and more fragment ions can be detected. This excitation method can be implemented easily without changing any experimental parameters.
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Affiliation(s)
- Qiankun Dang
- †Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China
| | - Fuxing Xu
- †Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China
| | - Xiaodong Xie
- †Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China
| | - Chongsheng Xu
- †Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China
| | - Xinhua Dai
- ‡National Institute of Metrology, Beijing 100013, China
| | - Xiang Fang
- ‡National Institute of Metrology, Beijing 100013, China
| | - Li Ding
- †Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China
| | - Chuan-Fan Ding
- †Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China
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