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Huo X, Gan L, Ding X, Yu Q, Zhou B, Zhou J, Qian X. A simple numerical simulation model can elucidate the key factors for designing a miniaturized ion trap mass spectrometer. Anal Chim Acta 2024; 1318:342943. [PMID: 39067922 DOI: 10.1016/j.aca.2024.342943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/30/2024]
Abstract
BACKGROUND Miniature ion trap mass spectrometer enables mass-to-charge ratio analysis of ions via quadrupole field in a low vacuum environment. It plays an important role in on-site detection due to its portability and specificity. In order to gain a deeper understanding of the analysis mechanism of miniature ion trap mass spectrometers, a quadrupole MS ion trajectory numerical simulation model (QITNS) is established in this paper for ions trajectory calculation under the action of quadrupole field, exciting field and neutral gas molecule collision. Compared with the existing methods, the model in this paper is simpler and more direct, which effectively explored the effects of dipole excitation and quadrupole excitation on ion manipulation under high background pressure. RESULTS The simulation results demonstrate that high RF amplitude, low auxiliary AC amplitude and quadrupole excitation can effectively improve the isolation resolution. Besides, it clarified the difference between the analysis mechanism of ion trap mass spectrometers under high background pressure (above 13.332 Pa) and absolute vacuum conditions. The relevant results are consistent with the conclusions of previous experiments and other theories, proving the applicability and accuracy of the proposed calculation model and solution method. SIGNIFICANCE This research bears the guiding significance for further understanding the mechanism of quadrupole mass spectrometry as well as designing and developing miniature mass spectrometers.
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Affiliation(s)
- Xinming Huo
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, People's Republic of China; Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China
| | - Lin Gan
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, People's Republic of China; Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China
| | - Xinyue Ding
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, People's Republic of China
| | - Quan Yu
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, People's Republic of China
| | - Bin Zhou
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, People's Republic of China; Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China
| | - Jianhua Zhou
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, People's Republic of China; Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China
| | - Xiang Qian
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, People's Republic of China.
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2
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Smith BL, Hankinson T, Maher S. Portable Instrumentation for Ambient Ionization and Miniature Mass Spectrometers. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2024; 17:69-102. [PMID: 38640067 DOI: 10.1146/annurev-anchem-061522-040824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
We critically evaluate the current status of portable mass spectrometry (pMS), particularly where this aligns with ambient ionization. Assessing the field of pMS can be quite subjective, especially in relation to the portable aspects of design, deployment, and operation. In this review, we discuss what it means to be portable and introduce a set of criteria by which pMS and ambient ionization sources can be assessed. Moreover, we consider the recent literature in terms of the most popular and significant advances in portable instrumentation for ambient ionization and miniature mass spectrometers. Finally, emerging trends and exciting future prospects are discussed and some recommendations are offered.
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Affiliation(s)
- Barry L Smith
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, United Kingdom;
| | - Thomas Hankinson
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, United Kingdom;
| | - Simon Maher
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, United Kingdom;
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3
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Cheng Y, Liu Y, Wu Z, Shen C, Li S, Wang H, Chen C. Concept and simulation of a novel dual-layer linear ion trap mass analyzer for micro-electromechanical systems mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2024; 30:150-160. [PMID: 38706254 DOI: 10.1177/14690667241251792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
This paper proposed a dual-layer linear ion trap mass analyzer (dLIT) based on micro-electromechanical systems (MEMS) technology and stacked-layer structure for the development of MEMS mass spectrometry. Its basic performance and potential capabilities were explored by ion trajectory simulations. The theoretical formulas were modified by implementing multipole expansion. The simulation results were confirmed to be highly consistent with theoretical calculations in multiple aspects, including stability diagram, secular frequencies, and mass linearity, with only a deviation of 1-2%. In the boundary ejection mode, close to 100% ejection was achieved in a single dimension by applying extra quadrupole DC voltage. Preliminary simulation results showed that dLIT can achieve a peak width of ∼2 mass units (full width at half maximum, FWHM) for m/z 60 ions even at pressures as high as 50 Pa. Furthermore, the application of AC frequency scanning mode in dLIT was also evaluated, and preliminary simulation results yield a peak width of 0.3-0.4 mass units (FWHM). The dLIT offered several advantages, including high-precision fabrication at the sub-millimeter scale, excellent high-pressure performance, and a clear physical model. It preliminarily proved to be an ideal mass analyzer for MEMS mass spectrometry.
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Affiliation(s)
- Yupeng Cheng
- University of Science and Technology of China, Hefei, China
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Youjiang Liu
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Zhangxu Wu
- University of Science and Technology of China, Hefei, China
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Chen Shen
- University of Science and Technology of China, Hefei, China
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Shan Li
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Han Wang
- University of Science and Technology of China, Hefei, China
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Chilai Chen
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
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4
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A comparison between mobile and stationary gas chromatography-mass spectrometry devices for analysis of complex volatile profiles. Anal Bioanal Chem 2023; 415:137-155. [PMID: 36396731 PMCID: PMC9672629 DOI: 10.1007/s00216-022-04391-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 08/25/2022] [Accepted: 10/18/2022] [Indexed: 11/18/2022]
Abstract
On-site analysis of volatile organic compounds (VOCs) with miniaturized gas chromatography-mass spectrometry (GC-MS) systems is a very rapidly developing field of application. While, on the one hand, major technological advances are improving the availability of these systems on the market, on the other hand, systematic studies to assess the performance of such instruments are still lacking. To fill this gap, we compared three portable GC-MS devices to a state-of-the-art benchtop (stationary) system for analysis of a standard mixture of 18 VOCs. We systematically compared analytical parameters such as the sensitivity and similarity of the signal response pattern and the quality of the obtained mass spectra. We found that the investigated mobile instruments (i) showed different response profiles with a generally lower number of identified analytes. Also, (ii) mass spectral reproducibility (% relative standard deviation (RSD) of the relative abundance of selective fragments) was generally worse in the mobile devices (mean RSD for all targeted fragments ~9.7% vs. ~3.5% in the stationary system). Furthermore, mobile devices (iii) showed a poorer mass spectral similarity to commercial reference library spectra (>20% deviation of fragment ion relative intensity vs. ~10% in the stationary GC-MS), suggesting a less reliable identification of analytes by library search. Indeed, (iv) the performance was better with higher-mass and/or more abundant fragments, which should be considered to improve the results of library searches for substance identification. Finally, (v) the estimation of the signal-to-noise ratio (S/N) in mobile instruments as a measure of sensitivity revealed a significantly lower performance compared to the benchtop lab equipment (with a ratio among medians of ~8 times lower). Overall, our study reveals not only a poor signal-to-noise ratio and poor reproducibility of the data obtained from mobile instruments, but also unfavorable results with respect to a reliable identification of substances when they are applied for complex mixtures of volatiles.
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5
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Wang J, Pursell ME, DeVor A, Awoyemi O, Valentine SJ, Li P. Portable mass spectrometry system: instrumentation, applications, and path to 'omics analysis. Proteomics 2022; 22:e2200112. [PMID: 36349734 PMCID: PMC10278091 DOI: 10.1002/pmic.202200112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/11/2022]
Abstract
Mass spectrometry (MS) is an information rich analytical technique and plays a key role in various 'omics studies. Standard mass spectrometers are bulky and operate at high vacuum, which hinder their adoption by the broader community and utility in field applications. Developing portable mass spectrometers can significantly expand the application scope and user groups of MS analysis. This review discusses the basics and recent advancements in the development of key components of portable mass spectrometers including ionization source, mass analyzer, detector, and vacuum system. Further, major areas where portable mass spectrometers are applied are also discussed. Finally, a perspective on the further development of portable mass spectrometers including the potential benefits for 'omics analysis is provided.
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Affiliation(s)
- Jing Wang
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Madison E. Pursell
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Amanda DeVor
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Olanrewaju Awoyemi
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Stephen J. Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Peng Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
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6
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Zhou X, Zhang W, Ouyang Z. Recent advances in on-site mass spectrometry analysis for clinical applications. Trends Analyt Chem 2022; 149:116548. [PMID: 35125564 PMCID: PMC8802081 DOI: 10.1016/j.trac.2022.116548] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In recent years, mass spectrometry (MS) is increasingly attracting interests for clinical applications, which also calls for technical innovations to make a transfer of MS from conventional analytical laboratories to clinics. The system design and analysis procedure should be friendly for novice users and appliable for on-site clinical diagnosis. In addition, the analysis result should be auto-interpreted and reported in formats much simpler than mass spectra. This motivates new ideas for developments in all the aspects of MS. In this review, we report recent advances of direct sampling ionization and miniature MS system, which have been developed targeting clinical and even point-of-care analysis. We also discuss the trend of the development and provide perspective on the technical challenges raised by diseases such as coronavirus SARS-CoV-2.
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Affiliation(s)
- Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Wenpeng Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
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7
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8
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Xu Q, Hong J, Liu S, Zhai Y, Xu W. Development of a miniature protein mass spectrometer capable of analyzing native proteins. Talanta 2021; 233:122580. [PMID: 34215072 DOI: 10.1016/j.talanta.2021.122580] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 12/19/2022]
Abstract
Current miniature mass spectrometers were usually designed for the detection of small and medium size molecules, including volatile (semi-volatile) compounds, drugs and lipids. In this study, a miniature protein mass spectrometer was developed in this work, which could serve as a biosensor for the rapid identification of proteins as well as their conformations. A linear ion trap with a field radius of 2.5 mm was designed to extend mass range of the instrument to over 6500 Th. Mass resolution and sensitivity of the instrument were also optimized for protein ions by increasing the buffer gas pressure and using a high-gain Faraday detector. It is then demonstrated that the mass spectra of native proteins, such as IgG1, could be acquired by coupling the instrument with a soft electrospray ionization source. As a proof-of-concept demonstration, results suggest that the current instrument could be used to identify target proteins and probe/distinguish their conformations in solutions.
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Affiliation(s)
- Qian Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Jie Hong
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Siyu Liu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Yanbing Zhai
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Wei Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
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9
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Abstract
The ion trap is a unique type of device that is used for quantum studies in physics and mass analysis in chemistry. The space charge effect, which is due to trapping of an excessive number of ions, has long been recognized to be harmful for ion manipulation or mass spectrometry analysis. Here, we show an interesting phenomenon in which the energy exchange through collective interaction between the ion species could be effectively used for ion manipulation and high-quality mass measurement. This observation not only reveals a fundamentally interesting process in ion trap operation but also suggests a new alternative means for mass analysis.
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Affiliation(s)
- Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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10
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Abstract
Performing mass spectrometry in a low-vacuum environment can markedly reduce the cost, size, and power consumption of instrumentation by reducing the workload of the pumping system. Under a low-vacuum environment, ions in a quadrupole mass filter do not have sufficient kinetic energy in the axial direction to reach the detector for mass analysis. To resolve this problem and develop a mass spectrometer suitable for a low-vacuum environment, a mass analysis method is proposed where a drift gas is used to supply energy to the ions. A simulation model was constructed in COMSOL Multiphysics, and a simple experimental device was built to validate the proposed method. The simulation results showed that this method effectively solves these problems, and the obtained spectral peak was superior to that without drift gas flow regarding spectral peak intensity and width. The experimental results showed that the proposed method separated ions with different mass-to-charge ratios at a pressure of 20 Pa. This work provides a theoretical foundation for the development of low-vacuum mass spectrometry, which will promote portability, provide a lower threshold of use, and expand the fields of application for mass spectrometers.
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11
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Meng X, Tang C, Zhang C, Li D, Xu W, Zhai Y. A "Brick" Mass Spectrometer with Photoionization for Direct Analysis of Trace Volatile Compounds. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:961-968. [PMID: 32233377 DOI: 10.1021/jasms.0c00019] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
With high portability and favorable performance, miniature mass spectrometers have become one of the most attractive tools for on-site analysis of trace volatile compounds. Based on the "Brick" mass spectrometer (BMS) developed previously, a hand-held BMS integrated with a photoionization source (PI-BMS) was developed in this study for volatile compound analysis. With compact dimensions of 30 cm × 18.5 cm × 27.6 cm (length × width × height), the PI-BMS was equipped with a 10.6 eV UV lamp and capable of generating molecular ions. The capabilities of qualitative and quantitative analyses for different volatile samples were demonstrated and characterized. Under optimized conditions, high detection sensitivity in open air was obtained for the PI-BMS with a limit of detection (LOD) of ∼10 ppbv. As demonstrations of mixture analysis, four different fresh fruits were directly analyzed using PI-BMS, observing characteristic mass spectra for each type of fruit.
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Affiliation(s)
- Xiangzhi Meng
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Caowei Tang
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Changxin Zhang
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Dayu Li
- School of Computer Science and Engineering, Northeastern University, Shenyang, 110819, China
| | - Wei Xu
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yanbing Zhai
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
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12
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Huo X, Zhu X, Tang F, Zhang J, Zhang X, Yu Q, Wang X. Discontinuous Subatmospheric Pressure Interface Reduces the Gas Flow Effects on Miniature CAPI Mass Spectrometer. Anal Chem 2020; 92:3707-3715. [PMID: 31961668 DOI: 10.1021/acs.analchem.9b04824] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the range of miniature mass spectrometers, the miniature ion trap mass spectrometer with continuous atmospheric pressure interface (CAPI) shows good performance potential and advantages due to its excellent sensitivity and analysis speed. However, in previous cases, placing the ion trap directly near the skimmer aperture means it will suffer high gas shock, which may affect performance. In this study, an improved miniature CAPI ion trap mass spectrometer was developed by gas flow optimization. According to the experimental results, excessive gas flow affects stability and resolution. The impact of the gas flow can be effectively reduced by reducing the inner diameter of the skimmer and adding an additional lens element to move the ion trap away from the skimmer aperture. However, this method will affect the sensitivity of the instrument to some extent, so a discontinuous subatmospheric pressure interface (DSPI) was developed to reduce the gas flow effects and improve the comprehensive performance. When using the DSPI system with a 0.4 mm skimmer and entrance lens, the resolution for roxithromycin was up to 2800 at a scanning speed of 1015 Th/s, which was 3.4-fold higher that without DSPI. The dynamic range of concentration reached 4 orders of magnitude and the detection limit for repaglinide was as low as 1 ng/mL. This study offers a new approach to develop better miniature ion trap mass spectrometers and to extend their practical application.
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Affiliation(s)
- Xinming Huo
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.,Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.,Division of Life Science & Health, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Xuanyu Zhu
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.,Shenzhen CHIN Instrument Co., Ltd., Shenzhen 518052, China
| | - Fei Tang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Jian Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Xiaohua Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Quan Yu
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Xiaohao Wang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.,Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
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13
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Tang Y, Xu Q, Li D, Xu W. A mini mass spectrometer with a low noise Faraday detector. Analyst 2020; 145:3892-3898. [DOI: 10.1039/d0an00420k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A low noise Faraday detector and a data processing method were developed for a miniature ion trap mass spectrometer.
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Affiliation(s)
- Yang Tang
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Qian Xu
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Dayu Li
- School of Computer Science and Engineering
- Northeastern University
- Shenyang 110819
- China
| | - Wei Xu
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081
- China
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14
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Li M, Liu X, Zhou X, Ouyang Z. Ion-Neutral Collision Effects on Ion Trapping and Pseudopotential Depth in Ion Trap Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2750-2755. [PMID: 31659717 DOI: 10.1007/s13361-019-02344-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/07/2019] [Accepted: 09/25/2019] [Indexed: 06/10/2023]
Abstract
Ion trapping using radio-frequency (RF) devices has been widely used in mass spectrometry (MS). The pseudopotential well (PW) model enables the use of a pseudopotential depth, D, to evaluate the ion trapping capability of the RF devices in the pure electric field. It remains unclear how gas pressures regulate the ion trapping and D. Here, we calculated the D of a linear ion trap (LIT) from 1 mTorr to 2 Torr, a pressure range critical for the operation of the RF devices, through ion cloud simulations. Compared with the case of pure electric field, ion-neutral collision effects at pressures of 1 to 100 mTorr were beneficial for the ion trapping and revealed an optimal trapping depth, D, at around 10 mTorr. We explained the mechanism and validated the observation via ion trapping experiments performed in a home-made dual LIT mass spectrometer. We also showed that near the stability boundary, the RF heating became comparable with the D, which led to the decrement of ion trapping capability characterized by the available D.
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Affiliation(s)
- Ming Li
- NCS Testing Technology CO., Ltd, Beijing, 100081, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Xinwei Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.
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15
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Hou C, Xu Q, Zhang F, Jiang T, Xu W. Toward high pressure miniature protein mass spectrometer: Theory and initial results. JOURNAL OF MASS SPECTROMETRY : JMS 2019; 54:957-965. [PMID: 31697856 DOI: 10.1002/jms.4466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
Current miniature mass spectrometers mainly focus on the analyses of organic and small biological molecules. In this study, we explored the possibility of developing high resolution miniature ion trap mass spectrometers for whole protein analysis. Theoretical derivation, GPU assisted ion trajectory simulation, and initial experiments on home-developed "brick" mass spectrometer were carried out. Results show that ion-neutral collisions have smaller damping effect on large protein ions, and a higher buffer gas pressure should be applied during ion trap operations for protein ions. As a result, higher pressure ion trap operation not only benefits instrument miniaturization, but also improves mass resolution of protein ions. Dynamic mass scan rate and generation of low charge state protein ions are also found to be helpful in terms of improving mass resolutions. Theory and conclusions found in this work are also applicable in the development of benchtop mass spectrometers.
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Affiliation(s)
- Chenyue Hou
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Qian Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Fei Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Ting Jiang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Wei Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
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16
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A systems approach to clinical oncology uses deep phenotyping to deliver personalized care. Nat Rev Clin Oncol 2019; 17:183-194. [DOI: 10.1038/s41571-019-0273-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2019] [Indexed: 02/06/2023]
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17
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Xu Z, Jiang T, Xu Q, Zhai Y, Li D, Xu W. Pseudo-Multiple Reaction Monitoring (Pseudo-MRM) Mode on the “Brick” Mass Spectrometer, Using the Grid-SWIFT Waveform. Anal Chem 2019; 91:13838-13846. [DOI: 10.1021/acs.analchem.9b03315] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Zuqiang Xu
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Ting Jiang
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Qian Xu
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yanbing Zhai
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Dayu Li
- School of Computer Science and Engineering, Northeastern University, Shenyang, 110819, China
| | - Wei Xu
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
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18
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Mayer M, Baeumner AJ. A Megatrend Challenging Analytical Chemistry: Biosensor and Chemosensor Concepts Ready for the Internet of Things. Chem Rev 2019; 119:7996-8027. [DOI: 10.1021/acs.chemrev.8b00719] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Michael Mayer
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
| | - Antje J. Baeumner
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
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Decker TK, Zheng Y, Ruben AJ, Wang X, Lammert SA, Austin DE, Hawkins AR. A Microscale Planar Linear Ion Trap Mass Spectrometer. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:482-488. [PMID: 30542974 DOI: 10.1007/s13361-018-2104-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
The planar linear ion trap (PLIT) is a version of the two-dimensional linear quadrupole ion trap constructed using two facing dielectric substrates on which electrodes are lithographically patterned. In this article, we present a PLIT that was successfully miniaturized from a radius of 2.5 mm to a microscale radius of 800 μm (a scaling factor of 3.125). The mathematics concerning scaling an ion trap mass spectrometer are demonstrated-including the tradeoff between RF power and pseudopotential well depth. The time average power for the microscale PLIT is, at best, ~ 1/100 that of the PLIT but at a cost of potential well depth of ~ 1/10 the original. Experimental data using toluene/deuterated toluene and isobutylbenze to verify trap performance demonstrated resolutions around 1.5 Da at a pressure of 5.4 × 10-3 Torr. The microscale PLIT was shown to retain resolutions between 2.3 and 2.7 Da at pressures up to 42 × 10-3 Torr while consuming a factor of 3.38 less time average power than the unscaled PLIT. Graphical Abstract.
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Affiliation(s)
| | | | | | - Xiao Wang
- Brigham Young University, Provo, UT, USA
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20
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21
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Gilliland WM, Ramsey JM. Development of a Microchip CE-HPMS Platform for Cell Growth Monitoring. Anal Chem 2018; 90:13000-13006. [DOI: 10.1021/acs.analchem.8b03708] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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22
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Liu J, Tang W, Meng X, Zhan L, Xu W, Nie Z, Wang Z. Improving the Performance of the Mini 2000 Mass Spectrometer with a Triboelectric Nanogenerator Electrospray Ionization Source. ACS OMEGA 2018; 3:12229-12234. [PMID: 31459297 PMCID: PMC6645661 DOI: 10.1021/acsomega.8b01777] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/13/2018] [Indexed: 06/10/2023]
Abstract
Balancing the contradiction between portability and analytical performances of a miniaturized mass spectrometer is vital to extend its on-site applications. In this study, triboelectric nanogenerator (TENG)-driven ion sources were coupled with our home-built Mini 2000 system and applied to the analyses of different samples. Compared with the conventional direct current (DC) nanoelectrospray ionization (nanoESI) source, the ion intensity of the TENG-nanoESI miniature mass spectrometer was improved by ∼3 times. Moreover, maybe due to the different pathways of ion formation in comparison with DC electrospray, TENG electrospray is shown to reduce the salt suppression effect during ionization. With these figures of merit, the direct detection of reserpine in saliva was demonstrated using the TENG-Mini 2000 system.
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Affiliation(s)
- Jianli Liu
- School
of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Wei Tang
- Beijing
Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China
| | - Xiangzhi Meng
- School
of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Lingpeng Zhan
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory for Analytical
Chemistry for Living Biosystems, Institute
of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
| | - Wei Xu
- School
of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Zongxiu Nie
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory for Analytical
Chemistry for Living Biosystems, Institute
of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
| | - Zhonglin Wang
- Beijing
Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332-0245, United States
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23
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Zhou X, Liu X, Cao W, Wang X, Li M, Qiao H, Ouyang Z. Study of In-Trap Ion Clouds by Ion Trajectory Simulations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:223-229. [PMID: 29043486 DOI: 10.1007/s13361-017-1814-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 08/29/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
Gaussian distribution has been utilized to describe the global number density distribution of ion cloud in the Paul trap, which is known as the thermal equilibrium theory and widely used in theoretical modeling of ion clouds in the ion traps. Using ion trajectory simulations, however, the ion clouds can now also be treated as a dynamic ion flow field and the location-dependent features could now be characterized. This study was carried out to better understand the in-trap ion cloud properties, such as the local particle velocity and temperature. The local ion number densities were found to be heterogeneously distributed in terms of mean and distribution width; the velocity and temperature of the ion flow varied with pressure depending on the flow type of the neutral molecules; and the "quasi-static" equilibrium status can only be achieved after a certain number of collisions, for which the time period is pressure-dependent. This work provides new insights of the ion clouds that are globally stable but subjected to local rf heating and collisional cooling. Graphical Abstract ᅟ.
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Affiliation(s)
- Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Xinwei Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Wenbo Cao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Xiao Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Ming Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Haoxue Qiao
- Department of Physics, Wuhan University, Wuhan, 430072, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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24
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Gilliland WM, Mellors JS, Ramsey JM. Coupling Microchip Electrospray Ionization Devices with High Pressure Mass Spectrometry. Anal Chem 2017; 89:13320-13325. [DOI: 10.1021/acs.analchem.7b03484] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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25
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Lu X, Yu Q, Zhang Q, Ni K, Qian X, Tang F, Wang X. Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1702-1708. [PMID: 28432655 DOI: 10.1007/s13361-017-1683-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 04/06/2017] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples. Graphical Abstract ᅟ.
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Affiliation(s)
- Xinqiong Lu
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing, 100084, China
| | - Quan Yu
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China.
| | - Qian Zhang
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Kai Ni
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Xiang Qian
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Fei Tang
- State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing, 100084, China
| | - Xiaohao Wang
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China.
- State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing, 100084, China.
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26
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Jiang T, Zhang H, Tang Y, Zhai Y, Xu W, Xu H, Zhao X, Li D, Xu W. A “Brick Mass Spectrometer” Driven by a Sinusoidal Frequency Scanning Technique. Anal Chem 2017; 89:5578-5584. [DOI: 10.1021/acs.analchem.7b00719] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ting Jiang
- State
Key Laboratory of Explosion Science and Technology, School of Life
Science, Beijing Institute of Technology, Beijing 100081, China
| | - Hongjia Zhang
- School
of Computer Science and Engineering, Northeastern University, Shenyang, 110819, China
| | - Yang Tang
- State
Key Laboratory of Explosion Science and Technology, School of Life
Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yanbing Zhai
- State
Key Laboratory of Explosion Science and Technology, School of Life
Science, Beijing Institute of Technology, Beijing 100081, China
| | - Wei Xu
- State
Key Laboratory of Explosion Science and Technology, School of Life
Science, Beijing Institute of Technology, Beijing 100081, China
| | - Hualei Xu
- State
Key Laboratory of Explosion Science and Technology, School of Life
Science, Beijing Institute of Technology, Beijing 100081, China
| | - Xinying Zhao
- Beijing Center Physical and Chemical Analysis, Beijing, 100089, China
| | - Dayu Li
- School
of Computer Science and Engineering, Northeastern University, Shenyang, 110819, China
| | - Wei Xu
- State
Key Laboratory of Explosion Science and Technology, School of Life
Science, Beijing Institute of Technology, Beijing 100081, China
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27
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Cox JR, Alsenani M, Miller SE, Roush JA, Shi R, Ow H, Chang S, Kmetz AA, Eichmann SL, Poitzsch ME. Pyrolyzable Nanoparticle Tracers for Environmental Interrogation and Monitoring. ACS APPLIED MATERIALS & INTERFACES 2017; 9:13111-13120. [PMID: 28291944 DOI: 10.1021/acsami.6b16050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Environmental tracing applications require materials that can be detected in complex fluids composed of multiple phases and contaminants. Moreover, large libraries of tracers are necessary in order to mitigate memory effects and to deploy multiple tracers simultaneously in complex oil fields. Herein, we disclose a novel approach based on the thermal decomposition of polymeric nanoparticles comprised of styrenic and methacrylic monomers. Polymeric nanoparticles derived from these monomers cleanly decompose into their constituent monomers at elevated temperatures, thereby maximizing atom economy wherein the entire nanoparticle mass contributes to the generation of detectable units. A total of ten unique single monomer particles and three dual-monomer particles were synthesized using semicontinuous monomer starved addition polymerization. The pyrolysis gas chromatography-flame ionization detection/mass spectrometry (GC-FID/MS) behavior of these particles was studied using high-pressure mass spectrometry. The programmable nature of our methodology permits simultaneous removal of contaminants and subsequent identification and quantification in a single analytical step.
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Affiliation(s)
- Jason R Cox
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Mohammed Alsenani
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Scott E Miller
- 908 Devices Inc. , 27 Drydock Avenue, Boston, Massachusetts 02210, United States
| | - James A Roush
- 908 Devices Inc. , 27 Drydock Avenue, Boston, Massachusetts 02210, United States
| | - Rena Shi
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Hooisweng Ow
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Sehoon Chang
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Anthony A Kmetz
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Shannon L Eichmann
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
| | - Martin E Poitzsch
- Aramco Research Center-Boston, Aramco Services Company , 400 Technology Square, Cambridge, Massachusetts 02139, United States
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28
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Blakeman KH, Cavanaugh CA, Gilliland WM, Ramsey JM. High pressure mass spectrometry of volatile organic compounds with ambient air buffer gas. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:27-32. [PMID: 27747956 DOI: 10.1002/rcm.7766] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE There are many chemical measurement scenarios that would benefit from hand portable mass spectrometry tools including forensics, environmental monitoring, and safety and security. High pressure mass spectrometry (HPMS) facilitates miniaturization by significantly reducing vacuum system requirements. Previous work demonstrated HPMS using helium buffer gas, but HPMS conducted using ambient air would further reduce the size and weight of a portable instrument while also reducing logistical demands by eliminating the need for a helium supply. METHODS Mass spectrometry was performed at pressures exceeding 1 Torr with ambient air as the buffer gas. A glow discharge electron ionization source and a miniature cylindrical ion trap mass analyzer with a radius of 0.5 mm were used. Mass analysis was possible at these pressures with increased radiofrequency (RF) drive frequencies (10 MHz) compared with commercial ion traps (~1 MHz). A differentially pumped chamber was used so that mass spectrometry could be performed at high pressures and detection performed at low pressures with an electron multiplier. RESULTS HPMS with air buffer gas was demonstrated using a suite of volatile organic compounds (VOCs). The glow discharge ionization source was optimized for operation using air. Mass spectral peak widths increased a factor of 8 compared with helium, as expected, but useful chemical information was still acquired. A mixture of VOCs was detected with ambient air as the buffer gas, showing that valuable mass information can be gained using HPMS without the requirement of an onboard buffer gas source. CONCLUSIONS HPMS significantly reduces the pumping requirements required for miniature mass spectrometers and the use of ambient air buffer gas further reduces size, weight, and logistics requirements. Mass analysis at high pressures of ambient air is another important step for the development of hand portable mass spectrometers. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Kenion H Blakeman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Craig A Cavanaugh
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - William M Gilliland
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - J Michael Ramsey
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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29
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30
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Snyder DT, Cooks RG. Successive Resonances for Ion Ejection at Arbitrary Frequencies in an Ion Trap. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1922-1928. [PMID: 27600577 DOI: 10.1007/s13361-016-1473-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/29/2016] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
The use of successive resonances for ion ejection is demonstrated here as a method of scanning quadrupole ion traps with improvement in both resolution and sensitivity compared with single frequency resonance ejection. The conventional single frequency resonance ejection waveform is replaced with a dual-frequency waveform. The two included frequencies are spaced very closely and their relative amplitudes are adjusted so that the first frequency that ions encounter excites them to higher amplitudes where space charge effects are less prominent, thereby giving faster and more efficient ejection when the ions come into resonance with the second frequency. The method is applicable at any arbitrary frequency, unlike double and triple resonance methods. However, like double and triple resonance ejection, ejection using successive resonances requires the rf and AC waveforms to be phase-locked in order to retain mass accuracy and mass precision. The improved performance is seen in mass spectra acquired by rf amplitude scans (resonance ejection) as well as by secular frequency scans. Graphical Abstract ᅟ.
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Affiliation(s)
- Dalton T Snyder
- Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA
| | - R Graham Cooks
- Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA.
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31
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Snyder DT, Pulliam CJ, Cooks RG. Linear mass scans in quadrupole ion traps using the inverse Mathieu q scan. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:2369-2378. [PMID: 27496220 DOI: 10.1002/rcm.7710] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/01/2016] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Secular frequency scanning is a method of mass selectively scanning ions out of a quadrupole ion trap by linearly ramping the frequency of the resonance ejection signal through ion secular frequencies at constant rf amplitude and frequency. The method is electronically much simpler than resonance ejection but it requires a complex nonlinear calibration procedure to correlate mass-to-charge with time. METHODS A method of secular frequency scanning in quadrupole ion traps is described in which mass-to-charge is linear with time. This method, termed an "inverse Mathieu q scan", contrasts with linear frequency sweeping which requires a complex nonlinear mass calibration procedure. In the current method, mass scans are forced to be linear with time by scanning the frequency of the supplementary ac so that there is an inverse relationship between the ejected ion's Mathieu q parameter and time. RESULTS In all cases, excellent mass spectral linearity is observed. The rf amplitude is shown to control both the scan range and the scan rate, whereas the ac amplitude and scan rate influence the mass resolution. The scan rate depends linearly on the rf amplitude, a unique feature of this scan. Although changes in either rf or ac amplitude affect the positions of peaks in time, they do not change the mass calibration procedure since this only requires a simple linear fit of m/z vs time. Space charge effects are shown to give rise to significant changes in resolution as well as to mass shifts. CONCLUSIONS A method of secular frequency scanning which provides a linear mass scale has been demonstrated. The inverse Mathieu q scan offers a significant increase in mass range and power savings while maintaining access to linearity, paving the way for a mass spectrometer based completely on ac waveforms for ion isolation, ion activation, and ion ejection. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Dalton T Snyder
- Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA
| | - Christopher J Pulliam
- Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA
| | - R Graham Cooks
- Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA.
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