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Zhan C, Ju Z, Xie B, Chen J, Ma Q, Li M. Signal processing for miniature mass spectrometer based on LSTM-EEMD feature digging. Talanta 2024; 281:126904. [PMID: 39326111 DOI: 10.1016/j.talanta.2024.126904] [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: 06/07/2024] [Revised: 09/09/2024] [Accepted: 09/16/2024] [Indexed: 09/28/2024]
Abstract
Miniature mass spectrometers exhibit immense application potential in on-site detection due to their small size and low cost. However, their detection accuracy is severely affected by factors such as sample pre-processing and environmental conditions. In this study, we propose a data processing method based on long short-term memory-ensemble empirical mode decomposition (LSTM-EEMD) to improve the quality of on-site detection data from miniature mass spectrometers. The EEMD method can clearly decompose the different physical feature components in the small-scale spectrometer signals, while the LSTM method can adaptively learn the internal feature relationships of the signals. Thus, by combining the two, the parameters for the EEMD signal reconstruction can be optimized in an adaptive manner, obtaining the optimized coefficients. Compared to the previous EEMD feature enhancement approach, the LSTM-EEMD method not only significantly improves the coefficient of determination (R2) and relative standard deviation (RSD) of the data, enhancing the linear range, but also achieves fully adaptive processing throughout the workflow, greatly boosting the efficiency. By leveraging a miniature mass spectrometer, data for N-acetyl-l-aspartic acid (NAA), 2-Hydroxyglutarate (2-HG), and γ-Aminobutyric acid (GABA) in actual blood samples have been obtained. The experimental results demonstrate that the LSTM-EEMD method can markedly enhance the accuracy and usability of the biological sample data in practical testing, providing new perspectives and possibilities for research and applications in the relevant domain.
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Affiliation(s)
- Chenrui Zhan
- School of Electrical and Control Engineering, North China University of Technology, Beijing, 100144, China
| | - Zisheng Ju
- Chinese Academy of Inspection and Quarantine, Beijing, 100176, China; State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Binrui Xie
- School of Electrical and Control Engineering, North China University of Technology, Beijing, 100144, China
| | - Jiwen Chen
- School of Electrical and Control Engineering, North China University of Technology, Beijing, 100144, China
| | - Qiang Ma
- Chinese Academy of Inspection and Quarantine, Beijing, 100176, China.
| | - Ming Li
- School of Electrical and Control Engineering, North China University of Technology, Beijing, 100144, China.
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Zhai Y, Fu X, Xu W. Miniature mass spectrometers and their potential for clinical point-of-care analysis. MASS SPECTROMETRY REVIEWS 2024; 43:1172-1191. [PMID: 37610153 DOI: 10.1002/mas.21867] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 08/04/2023] [Accepted: 08/11/2023] [Indexed: 08/24/2023]
Abstract
Mass spectrometry (MS) has become a powerful technique for clinical applications with high sensitivity and specificity. Different from conventional MS diagnosis in laboratory, point-of-care (POC) analyses in clinics require mass spectrometers and analytical procedures to be friendly for novice users and applicable for on-site clinical diagnosis. The recent decades have seen the progress in the development of miniature mass spectrometers, providing a promising solution for clinical POC applications. In this review, we report recent advances of miniature mass spectrometers and their exploration in clinical applications, mainly including the rapid analysis of illegal drugs, on-site monitoring of therapeutic drugs, and detection of biomarkers. With improved analytical performance, miniature mass spectrometers are also expected to apply to more and more clinical applications. Some promising POC analyses that can be performed by miniature mass spectrometers in the future are discussed. Lastly, we also provide our perspectives on the challenges in technical development of miniature mass spectrometers for clinical POC analysis.
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Affiliation(s)
- Yanbing Zhai
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
| | - Xinyan Fu
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
| | - Wei Xu
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
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Li A, Sun J, Yan H, Li D, Xu W. SAM-SFM: High-Efficiency and High-Resolution Tandem Mass Spectrometry Enabled by Sinusoidal Amplitude Modulation of Multiple Sinusoidal Frequency-Modulated Waveforms. Anal Chem 2024; 96:2183-2190. [PMID: 38247304 DOI: 10.1021/acs.analchem.3c05156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
In miniature ion trap mass spectrometry, achieving a balance between isolation resolution and efficiency is a formidable challenge. The presence of absorption curves causes target ions to inadvertently absorb energy from AC signal components near their resonant frequencies. To mitigate this issue, SAM-SFM waveforms introduce a parameter known as the decreasing factor. Unlike SWIFT waveforms, SAM-SFM's spectral profile intentionally departs from a rectangular window, adopting an arch-shaped excitation window to minimize the impact on target ions and improve ion isolation efficiency. SAM-SFM waveforms have the advantage of low computational complexity, enabling real-time computation using an embedded FPGA technology. Regardless of any parameter changes, the FPGA can consistently guarantee waveform output within 1 μs. This not only enhances throughput but also eliminates the need for a PC in miniature mass spectrometry devices. The performance of SAM-SFM has been validated on an improved "Brick" miniature ion trap mass spectrometer. Comparative experiments with SWIFT waveforms confirm the lossless unit-mass isolation capabilities of SAM-SFM. This waveform has the capability to simultaneously isolate multiple target ions, even allowing for the lossless isolation of ions with lower abundance within isotopic clusters, albeit at the cost of requiring extended isolation durations.
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Affiliation(s)
- Ang Li
- School of Computer Science and Engineering, Northeastern University, Shenyang 110819, China
| | - Jian Sun
- The Institute for Advanced Studies, Wuhan University, Wuhan, Hubei 430072, China
| | - Haoqiang Yan
- School of Computer Science and Engineering, Northeastern University, Shenyang 110819, 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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Sun S, Hou M, Lai C, Yang Q, Gao J, Lu X, Wang X, Yu Q. Capillary self-aspirating electrospray ionization (CSESI) for convenient and versatile mass spectrometry analysis. Talanta 2024; 266:125008. [PMID: 37531883 DOI: 10.1016/j.talanta.2023.125008] [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: 05/20/2023] [Revised: 07/22/2023] [Accepted: 07/28/2023] [Indexed: 08/04/2023]
Abstract
Electrospray ionization (ESI) is one of the most widely used ionization techniques, and its simplification can benefit many interested users. In this study, sample introduction by capillary action was studied and used to develop a simple ESI source called capillary self-aspirating electrospray ionization (CSESI). A conventional CSESI source requires only a common capillary of appropriate diameter in addition to the support of high voltage (HV). No pumps and sample loading is needed because the solution can spontaneously climb across the capillary by capillary action. With the proper modification of the glass capillary, the operation of CSESI can be further simplified and efficient. Specifically, cold plasma processing of the capillary creates a more hydrophilic surface that can facilitate sample introduction. Moreover, sputtering a thin platinum layer on the capillary tip makes the application of HV more convenient, and it also eliminates the influence of air bubbles in the capillary to ensure a sustained and stable electrospray. Overall, CSESI exhibits multiple desirable features such as simple structure, self-aspiration ability, low sample consumption, and inherent physical filtration capability. Apart from the routine ESI-MS analysis, it has also been applied in real-time monitoring of the oxidative dimerization of 8-methyl-1,2,3,4-tetrahydroquinoline, as well as direct analysis of muddy soil solutions without pretreatment.
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Affiliation(s)
- Shuang Sun
- Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Mulang Hou
- Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Chaoyang Lai
- Shenzhen Chin Instrument Co., Ltd., Shenzhen, 518055, China
| | - Qin Yang
- Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Jing Gao
- Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Xinqiong Lu
- Shenzhen Chin Instrument Co., Ltd., Shenzhen, 518055, China
| | - Xiaohao Wang
- Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Quan Yu
- Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
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Zhang H, Jia H, Hong J, Zhang M, Jiang T, Xu W. Development of a High-Field "Brick" Mass Spectrometer with Extended Mass Range and Capable of Characterizing Native Proteins. Anal Chem 2023; 95:13503-13508. [PMID: 37650728 DOI: 10.1021/acs.analchem.3c01769] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
One of the main challenges of analyzing intact proteins on an ion trap mass spectrometer is the mass range limitation, especially for miniature mass spectrometers. In this study, a high-field frequency scanning ion trap miniature mass spectrometer, namely the high-field "Brick" mass spectrometer, was developed to analyze intact proteins. A high-voltage broadband radio frequency (rf) amplifier was designed with a maximum output of 900 Vp-p over a frequency range of 130-700 kHz. Compared to the 600 Vp-p rf amplifier equipped in the conventional "Brick" mass spectrometer, the mass range of the instrument could be extended from 2000 to over 8000 Th. Sensitivity and mass resolution for native protein analyses were also evaluated and compared. Various proteins as well as their mixtures were analyzed on the high-field "Brick" mass spectrometer. The noncovalent interaction between protein-ligand complexes, lysozyme with triN-acetylchitotriose, was also analyzed. In addition, a hybrid ion scan mode was explored to further expand the mass range of the instrument at both low- and high-mass ends. In the hybrid ion scan mode, both rf frequency and amplitude were tuned, and a mass range from 100 to 12,000 Th was realized. As a result, both small drugs and proteins could be analyzed in a single mass scan. As proof-of-concept demonstrations, a mixture of atenolol and bovine serum albuminand oligomers of transferrin were analyzed.
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Affiliation(s)
- Hongjia Zhang
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Heyuan Jia
- Kunshan Nier Precision Instrumentation Inc., Kunshan, Suzhou 215316, China
| | - Jie Hong
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Mei Zhang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Ting Jiang
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Wei Xu
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
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Patil AA, Liu ZX, Chiu YP, Lại TKL, Chou SW, Cheng CY, Su WM, Liao HT, Agcaoili JBA, Peng WP. Development of a linear ion trap mass spectrometer capable of analyzing megadalton MALDI ions. Talanta 2023; 259:124555. [PMID: 37088041 DOI: 10.1016/j.talanta.2023.124555] [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: 01/05/2023] [Revised: 04/02/2023] [Accepted: 04/11/2023] [Indexed: 04/25/2023]
Abstract
Detecting megadalton matrix-assisted laser desorption/ionization (MALDI) ions in an ion trap mass spectrometer is a technical challenge. In this study, megadalton protein and polymer ions were successfully measured by MALDI linear ion trap mass spectrometer (LIT-MS) for the first time. The LIT-MS is comprised of a Thermo linear ion trap mass analyzer and a highly sensitive charge-sensing particle detector (CSPD). A newly designed radio frequency (rf) scan mode with dipolar resonance ejection techniques is proposed to extend the mass range of LIT-MS up to one million Thomson (Th). We analyze high mass ions with mass-to charge (m/z) ratios ranging from 100 kTh to 1 MTh, including thyroglobulin, alpha-2-macroglobulin, immunoglobulins (e.g., IgG and IgM), and polymer (∼ 940 kTh) ions. Besides, it is also very challenging for ion trap mass spectrometry to detect megadalton ions at low concentrations. By adopting high affinity carboxylated/oxidized detonation nanodiamonds (oxDNDs) to enrich IgM molecules and form antibody-nanodiamond conjugates, we have successfully reached ∼ 5 nM (5 μg/mL) concentration which is better than that by the other techniques.
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Affiliation(s)
- Avinash A Patil
- Department of Physics, National Dong Hwa University, Shoufeng, Hualien, 97401, Taiwan
| | - Zhe-Xuan Liu
- Department of Physics, National Dong Hwa University, Shoufeng, Hualien, 97401, Taiwan
| | - Yi-Pang Chiu
- Department of Physics, National Dong Hwa University, Shoufeng, Hualien, 97401, Taiwan
| | - Thị Khánh Ly Lại
- Department of Physics, National Dong Hwa University, Shoufeng, Hualien, 97401, Taiwan
| | - Szu-Wei Chou
- AcroMass Technologies Inc., Hukou, Hsinchu, 30352, Taiwan
| | - Chun-Yen Cheng
- AcroMass Technologies Inc., Hukou, Hsinchu, 30352, Taiwan
| | - Wen-Min Su
- Department of Life Science, National Dong Hwa University, Hualien, 97401, Taiwan
| | - Hong-Ting Liao
- Department of Life Science, National Dong Hwa University, Hualien, 97401, Taiwan
| | | | - Wen-Ping Peng
- Department of Physics, National Dong Hwa University, Shoufeng, Hualien, 97401, Taiwan.
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Development and application of a miniature mass spectrometer with continuous sub-atmospheric pressure interface and integrated ionization source. Talanta 2023; 253:123994. [PMID: 36228556 DOI: 10.1016/j.talanta.2022.123994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/25/2022] [Accepted: 10/03/2022] [Indexed: 11/23/2022]
Abstract
For the miniature mass spectrometer (MS) with a continuous atmospheric pressure interface (CAPI), the gas in the multi-stage chambers directly affects the performance of the instrument. In this study, a sealed ionization chamber is designed to couple with a conventional mini CAPI-MS. In this configuration, the gas environment in the first ionization chamber can be flexibly changed to regulate the gas conditions throughout the entire instrument. By studying the effect of gas pressure on the performance of the instrument, we found that the instrument shows some unique advantages when the first ionization chamber is under sub-atmospheric pressure (SAP) conditions, such as reducing the load of the vacuum pump by 40%, achieving pump-free injection for gas and liquid samples, and improving the resolution by a factor of 2 without loss of detection sensitivity. Therefore, we propose a new integrated interface called continuous sub-atmospheric pressure interface (CSAPI) for building a miniature ion trap mass spectrometer. The CSAPI specially integrates sample introduction, gas/ions interface, and ionizations, including electrospray ionization (ESI) and secondary electrospray ionization (SESI), making this system more convenient for non-professional handlers to rapidly identify or monitor target analytes in gaseous- and solution-phase samples. We also use this system to study gas composition to further improve performance, being able to achieve a 5-fold sensitivity and 2-fold resolution improvement. At last, some custom applications of the current CSAPI-MS platform are explored and demonstrated, including real-time monitoring of chemical reactions in solution and long-distance sampling and analysis of dried Chinese herbs. In conclusion, this study provides a new approach to constructing a complete, versatile and practical miniature MS instrument.
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Liu R, Xia S, Li H. Native top-down mass spectrometry for higher-order structural characterization of proteins and complexes. MASS SPECTROMETRY REVIEWS 2022:e21793. [PMID: 35757976 DOI: 10.1002/mas.21793] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Progress in structural biology research has led to a high demand for powerful and yet complementary analytical tools for structural characterization of proteins and protein complexes. This demand has significantly increased interest in native mass spectrometry (nMS), particularly native top-down mass spectrometry (nTDMS) in the past decade. This review highlights recent advances in nTDMS for structural research of biological assemblies, with a particular focus on the extra multi-layers of information enabled by TDMS. We include a short introduction of sample preparation and ionization to nMS, tandem fragmentation techniques as well as mass analyzers and software/analysis pipelines used for nTDMS. We highlight unique structural information offered by nTDMS and examples of its broad range of applications in proteins, protein-ligand interactions (metal, cofactor/drug, DNA/RNA, and protein), therapeutic antibodies and antigen-antibody complexes, membrane proteins, macromolecular machineries (ribosome, nucleosome, proteosome, and viruses), to endogenous protein complexes. The challenges, potential, along with perspectives of nTDMS methods for the analysis of proteins and protein assemblies in recombinant and biological samples are discussed.
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Affiliation(s)
- Ruijie Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shujun Xia
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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