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Ai J, Zhao W, Yu Q, Qian X, Zhou J, Huo X, Tang F. SR-Unet: A Super-Resolution Algorithm for Ion Trap Mass Spectrometers Based on the Deep Neural Network. Anal Chem 2023; 95:17407-17415. [PMID: 37963290 DOI: 10.1021/acs.analchem.3c04172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
The mass spectrometer is an important tool for modern chemical analysis and detection. Especially, the emergence of miniature mass spectrometers has provided new tools for field analysis and detection. The resolution of a mass spectrometer reflects the ability of the instrument to discriminate between adjacent mass-to-charge ratio ions, and the higher the resolution, the better the discrimination of complex mixtures. Quadrupole ion traps are generally considered as a low-resolution mass spectrometry method, but they have gained wide attention and development in recent years because of their suitability for miniaturization and high qualitative capability. For an ion trap mass spectrometer, the mass sensitivity and resolution can be mutually constrained and need to be balanced by setting an appropriate scanning speed. In this study, a super-resolution U-net algorithm (SR-Unet) is proposed for ion trap mass spectrometry, which can estimate the possible ions from the overlapping ion peaks of low-resolution spectra and improve the equivalent resolution while ensuring sufficient sensitivity and analysis speed of the instrument. By determining the mass spectra of a linear ion trap mass spectrometer (LTQ XL) in Turbo and Normal scan modes, the same unit mass resolution as that at a scan speed of 16,667 Da/s was successfully obtained at 125,000 Da/s. Also, the experiments demonstrated that the algorithm is capable of the mass-to-charge ratio and instrument migration. SR-Unet can be migrated and applied to a miniature mass spectrometer for cruise detection of volatile organic compounds (VOCs), and the identification of VOC species in Photochemical Assessment Monitoring Stations (PAMS) was improved from 31 to 50 species with the same monitoring and analysis speed requirement. Further, super-unit mass resolution peptide detection was achieved on a miniature mass spectrometer with the help of the SR-Unet algorithm, which reduced the full width at half-maxima (FWHM) of bradykinin divalent ions (m/z 531) from 0.35 to 0.15 Da at a scan speed of 375 Da/s and improved the equivalent resolution to 3540. The proposed method provides a new idea to enhance the field mixture detection capability of miniature ion trap mass spectrometers.
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Affiliation(s)
- Jiawen Ai
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Weize Zhao
- Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Quan Yu
- 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
| | - Jianhua Zhou
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-Sen University, Shenzhen 518107, China
- Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Xinming Huo
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-Sen University, Shenzhen 518107, China
- Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Fei Tang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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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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Shi W, Huo X, Ding X, Zhu P, Wan Y, Lu X, Feng R, Yu Q, Wang X. Rapid screening of illegally added drugs in functional food using a miniature ion trap mass spectrometer. Food Chem 2022; 386:132808. [PMID: 35364493 DOI: 10.1016/j.foodchem.2022.132808] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 11/04/2022]
Abstract
With the expansion of the functional food market, the qualification assessment of these products has become a major challenge, and efficient analytical tools are urgently needed. Here, a miniature mass spectrometer (MS) with self-aspiration capillary electrospray ionization (SACESI) source and ion trap analyzer was developed for rapid screening of various illegally added drugs in functional foods. No chromatographic separation was required, but a simplified two-step pretreatment method was developed to reduce the operational procedures and time consumption of the entire analysis. SACESI source uses capillary action to drive solution injection, which utilizes a simple structure and convenient operation to constitute a kind of disposable MS detection solution. To achieve accurate and automatic identification, an intelligent recognition algorithm with steps of spectrum preprocessing, characteristic peak matching, and support vector machine learning was constructed. The relative accuracy of rapid screening of 31 suspicious drugs in various samples is up to 99.78%. It achieves 100% correct identification for the 55 batches of actual samples captured by on-site inspection, which demonstrates the feasibility of the proposed analytical system and strategy in food safety applications.
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Affiliation(s)
- Wenyan Shi
- Division of Advanced Manufacturing, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Xinming Huo
- School of Biomedical Engineering, Sun Yat-sen University, Shenzhen 518107, China.
| | - Xinyue Ding
- Division of Advanced Manufacturing, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Peiyuan Zhu
- Shenzhen Han Industrial Technologies Co.Ltd., Shenzhen 518055, China
| | - Yutong Wan
- Shenzhen Chin Instrument Co., Ltd., Shenzhen 518055, China
| | - Xinqiong Lu
- Shenzhen Chin Instrument Co., Ltd., Shenzhen 518055, China
| | - Rui Feng
- Research Institute for Frontier Science, Beihang University, Beijing 100191, China
| | - Quan Yu
- Division of Advanced Manufacturing, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Xiaohao Wang
- Division of Advanced Manufacturing, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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Lee S, Chintalapudi K, Badu-Tawiah AK. Clinical Chemistry for Developing Countries: Mass Spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2021; 14:437-465. [PMID: 33979544 PMCID: PMC8932337 DOI: 10.1146/annurev-anchem-091520-085936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Early disease diagnosis is necessary to enable timely interventions. Implementation of this vital task in the developing world is challenging owing to limited resources. Diagnostic approaches developed for resource-limited settings have often involved colorimetric tests (based on immunoassays) due to their low cost. Unfortunately, the performance/sensitivity of such simplistic tests are often limited and significantly hinder opportunities for early disease detection. A new criterion for selecting diagnostic tests in low- and middle-income countries is proposed here that is based on performance-to-cost ratio. For example, modern mass spectrometry (MS) now involves analysis of the native sample in the open laboratory environment, enabling applications in many fields, including clinical research, forensic science, environmental analysis, and agriculture. In this critical review, we summarize recent developments in chemistry that enable MS to be applied effectively in developing countries. In particular, we argue that closed automated analytical systems may not offer the analytical flexibility needed in resource-limited settings. Alternative strategies proposed here have potential to be widely accepted in low- and middle-income countries through the utilization of the open-source ambient MS platform that enables microsampling techniques such as dried blood spot to be coupled with miniature mass spectrometers in a centralized analytical platform. Consequently, costs associated with sample handling and maintenance can be reduced by >50% of the total ownership cost, permitting analytical measurements to be operated at high performance-to-cost ratios in the developing world.
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Affiliation(s)
- Suji Lee
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA;
| | - Kavyasree Chintalapudi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA;
| | - Abraham K Badu-Tawiah
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA;
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Yu Z, Li Y. Marine volatile organic compounds and their impacts on marine aerosol-A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 768:145054. [PMID: 33736323 DOI: 10.1016/j.scitotenv.2021.145054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/04/2021] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Volatile organic compounds (VOCs) play a vital role in the global carbon budget and in the regional formation of ozone in the troposphere, and are emitted from both natural and anthropogenic activities. They can also serve as a source of secondary organic aerosol (SOA). Field and model studies showed evidences of a strong marine biogenic influence on marine aerosols. Although knowledge of terrestrial VOC emissions and SOA formation mechanisms has been advanced considerably over the last decades, processes constraining marine VOC emissions and marine SOA formation remain poorly understood. Seawater contains an extremely complex, diverse, and largely unidentified mixture of VOCs. Despite the fact that the ocean covers 70% of the Earth's surface, the role of the ocean in the global budget of VOCs is still unclear. The distribution and emission of sea surface VOCs exhibit considerable spatial-temporal variation, with higher concentrations often, but not always, correlated with biological activities. VOCs in surface seawater have been measured in various geographic regions, however, knowledge of the distribution of marine VOCs and the role of the oceans in the global atmospheric chemistry is still insufficient due to the paucity of measurements. This study reviews marine VOCs in terms of current analytical methods, global marine VOCs measurements, their effects on SOA, and future needs for understanding the role of marine VOCs in the chemistry of the atmosphere.
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Affiliation(s)
- Zhujun Yu
- Department of Ocean Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd, Nanshan District, Shenzhen, Guangdong 518055, China
| | - Ying Li
- Department of Ocean Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd, Nanshan District, Shenzhen, Guangdong 518055, China; Center for Oceanic and Atmospheric Science at SUSTech (COAST), Southern University of Science and Technology, Shenzhen, China.
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Shi W, Huo X, Tian Y, Lu X, Yang L, Zhou Q, Wang X, Yu Q. Development of membrane inlet photoionization ion trap mass spectrometer for trace VOCs analysis. Talanta 2021; 230:122352. [PMID: 33934800 DOI: 10.1016/j.talanta.2021.122352] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/10/2021] [Accepted: 03/17/2021] [Indexed: 12/01/2022]
Abstract
With the development of instrumental miniaturization, the portable mass spectrometer is becoming a new tool for on-site rapid analysis of environmental samples. Membrane inlet (MI) and photoionization (PI) are two commonly used sampling and ionization techniques, respectively, as they both exhibit detection selectivity for volatile organic compounds (VOCs). In this paper, a membrane inlet photoionization ion trap mass spectrometer was developed for the direct analysis of VOCs in gaseous samples. With the new structure and timing design, various operation modes were proposed and tested. In particular, the use of pulse carrier gas can integrate the appropriate pressure conditions required by each module, thus improving the efficiency of analyte transport, ionization, and mass analysis. The detection limit of sub-ppb was obtained, and the response time can be greatly reduced by increasing the sample flow rate. Furthermore, the capability of selective enrichment for organic analytes was also realized by using a special accumulation mode with a modified sequence, which is easy to operate because no additional devices are needed.
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Affiliation(s)
- Wenyan Shi
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China; State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Xinming Huo
- Division of Life Science & Health, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Yuan Tian
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China
| | - Xinqiong Lu
- Shenzhen Chin Instrument Co., Ltd., Shenzhen, 518055, China.
| | - Lili Yang
- Measurement Technology and Instrumentation Key Lab of Hebei Province, Yanshan University, Qinhuangdao, Hebei, 066004, China
| | - Qian Zhou
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China
| | - Xiaohao Wang
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China; State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Quan Yu
- Division of Advanced Manufacturing, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China.
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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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