Pub Date : 2014-08-01DOI: 10.5702/massspectrometry.S0039
T. Nishioka, T. Kasama, T. Kinumi, H. Makabe, Fumio Matsuda, Daisuke Miura, M. Miyashita, Takemichi Nakamura, Kenichi Tanaka, Atsushi Yamamoto
CASMI (Critical Assessment of Small Molecule Identification) is a contest in which participants identify the molecular formula and chemical structure of challenging molecules using blind mass spectra as the challenge data. Seven research teams participated in CASMI2013. The winner of CASMI2013 was the team of Andrew Newsome and Dejan Nikolic, the University of Illinois at Chicago, IL, USA. The team identified 15 among 16 challenge molecules by manually interpreting the challenge data and by searching in-house and public mass spectral databases, and chemical substance and literature databases. MAGMa was selected as the best automated tool of CASMI2013. In some challenges, most of the automated tools successfully identified the challenge molecules, independent of the compound class and magnitude of the molecular mass. In these challenge data, all of the isotope peaks and the product ions essential for the identification were observed within the expected mass accuracy. In the other challenges, most of the automated tools failed, or identified solution candidates together with many false-positive candidates. We then analyzed these challenge data based on the quality of the mass spectra, the dissociation mechanisms, and the compound class and elemental composition of the challenge molecules.
CASMI (Critical Assessment of Small Molecule Identification)是一项竞赛，参赛者使用盲质谱作为挑战数据来识别挑战分子的分子式和化学结构。7个研究团队参与了CASMI2013。CASMI2013的冠军是美国伊利诺斯州芝加哥大学的Andrew Newsome和Dejan Nikolic团队。该团队通过人工解释挑战数据、搜索内部和公共质谱数据库、化学物质和文献数据库，确定了16个挑战分子中的15个。MAGMa被选为CASMI2013的最佳自动化工具。在一些挑战中，大多数自动化工具成功地识别了挑战分子，而不依赖于化合物类别和分子质量的大小。在这些挑战数据中，所有同位素峰和鉴定所需的产物离子都在预期的质量精度范围内观察到。在其他挑战中，大多数自动化工具都失败了，或者识别了解决方案候选以及许多假阳性候选。然后，我们根据质谱的质量、解离机制、挑战分子的化合物类别和元素组成来分析这些挑战数据。
{"title":"Winners of CASMI2013: Automated Tools and Challenge Data.","authors":"T. Nishioka, T. Kasama, T. Kinumi, H. Makabe, Fumio Matsuda, Daisuke Miura, M. Miyashita, Takemichi Nakamura, Kenichi Tanaka, Atsushi Yamamoto","doi":"10.5702/massspectrometry.S0039","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0039","url":null,"abstract":"CASMI (Critical Assessment of Small Molecule Identification) is a contest in which participants identify the molecular formula and chemical structure of challenging molecules using blind mass spectra as the challenge data. Seven research teams participated in CASMI2013. The winner of CASMI2013 was the team of Andrew Newsome and Dejan Nikolic, the University of Illinois at Chicago, IL, USA. The team identified 15 among 16 challenge molecules by manually interpreting the challenge data and by searching in-house and public mass spectral databases, and chemical substance and literature databases. MAGMa was selected as the best automated tool of CASMI2013. In some challenges, most of the automated tools successfully identified the challenge molecules, independent of the compound class and magnitude of the molecular mass. In these challenge data, all of the isotope peaks and the product ions essential for the identification were observed within the expected mass accuracy. In the other challenges, most of the automated tools failed, or identified solution candidates together with many false-positive candidates. We then analyzed these challenge data based on the quality of the mass spectra, the dissociation mechanisms, and the compound class and elemental composition of the challenge molecules.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"43 1","pages":"S0039"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80777287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-08-01DOI: 10.5702/massspectrometry.S0036
Emma L. Schymanski, Michael Gerlich, Christoph Ruttkies, S. Neumann
The second Critical Assessment of Small Molecule Identification (CASMI) contest took place in 2013. A joint team from the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and Leibniz Institute of Plant Biochemistry (IPB) participated in CASMI 2013 with an automatic workflow-style entry. MOLGEN-MS/MS was used for Category 1, molecular formula calculation, restricted by the information given for each challenge. MetFrag and MetFusion were used for Category 2, structure identification, retrieving candidates from the compound databases KEGG, PubChem and ChemSpider and joining these lists pre-submission. The results from Category 1 were used to guide whether formula or exact mass searches were performed for Category 2. The Category 2 results were impressive considering the database size and automated regime used, although these could not compete with the manual approach of the contest winner. The Category 1 results were affected by large m/z and ppm values in the challenge data, where strategies beyond pure enumeration from other participants were more successful. However, the combination used for the CASMI 2013 entries was extremely useful for developing decision-making criteria for automatic, high throughput general unknown (non-target) identification and for future contests.
{"title":"Solving CASMI 2013 with MetFrag, MetFusion and MOLGEN-MS/MS.","authors":"Emma L. Schymanski, Michael Gerlich, Christoph Ruttkies, S. Neumann","doi":"10.5702/massspectrometry.S0036","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0036","url":null,"abstract":"The second Critical Assessment of Small Molecule Identification (CASMI) contest took place in 2013. A joint team from the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and Leibniz Institute of Plant Biochemistry (IPB) participated in CASMI 2013 with an automatic workflow-style entry. MOLGEN-MS/MS was used for Category 1, molecular formula calculation, restricted by the information given for each challenge. MetFrag and MetFusion were used for Category 2, structure identification, retrieving candidates from the compound databases KEGG, PubChem and ChemSpider and joining these lists pre-submission. The results from Category 1 were used to guide whether formula or exact mass searches were performed for Category 2. The Category 2 results were impressive considering the database size and automated regime used, although these could not compete with the manual approach of the contest winner. The Category 1 results were affected by large m/z and ppm values in the challenge data, where strategies beyond pure enumeration from other participants were more successful. However, the combination used for the CASMI 2013 entries was extremely useful for developing decision-making criteria for automatic, high throughput general unknown (non-target) identification and for future contests.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"PP 1","pages":"S0036"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84551448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0031
Xianglei Kong, Zhaiyi Huo, W. Zhai
Chiral recognition of d- and l-amino acids is achieved by a method combining electrospray ionization (ESI) and in-source collision-induced dissociation (CID) mass spectrometry (MS). Trimeric cluster ions [Cu(II)(A)(ref)2-H](+) are formed by ESI of mixtures of d- or l-analyte amino acid (A), chiral reference (ref) and CuSO4. By increasing the applied voltage in the ESI source region, the trimeric ions become unstable and dissociate progressively. Thus chiral differentiation of the analyte can be achieved by comparing the dependence of their relative intensities to a reference ion on applied voltages. The method does not need MS/MS technique, thus can be readily performed on single-stage MS instruments by turning the voltage of sampling cone.
{"title":"Chiral Differentiation of Amino Acids by In-Source Collision-Induced Dissociation Mass Spectrometry.","authors":"Xianglei Kong, Zhaiyi Huo, W. Zhai","doi":"10.5702/massspectrometry.S0031","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0031","url":null,"abstract":"Chiral recognition of d- and l-amino acids is achieved by a method combining electrospray ionization (ESI) and in-source collision-induced dissociation (CID) mass spectrometry (MS). Trimeric cluster ions [Cu(II)(A)(ref)2-H](+) are formed by ESI of mixtures of d- or l-analyte amino acid (A), chiral reference (ref) and CuSO4. By increasing the applied voltage in the ESI source region, the trimeric ions become unstable and dissociate progressively. Thus chiral differentiation of the analyte can be achieved by comparing the dependence of their relative intensities to a reference ion on applied voltages. The method does not need MS/MS technique, thus can be readily performed on single-stage MS instruments by turning the voltage of sampling cone.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"250 1","pages":"S0031"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76791988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0028
Pui-kin So, Bin Hu, Z. Yao
Development of electrospray ionization on solid substrates (solid-substrate ESI) avoids the clogging problem encountered in conventional capillary-based ESI, allows more convenient sampling and permits new applications. So far, solid-substrate ESI with various materials, e.g., metals, paper, wood, fibers and biological tissue, has been developed, and applications ranging from analysis of pure compounds to complex mixtures as well as in vivo study were demonstrated. Particularly, the capability of solid-substrate ESI in direct analysis of complex samples, e.g., biological fluids and foods, has significantly facilitated mass spectrometric analysis in real-life applications and led to increasingly important roles of these techniques nowadays. In this review, various solid-substrate ESI techniques and their applications are summarized and the prospects in this field are discussed.
{"title":"Electrospray Ionization on Solid Substrates.","authors":"Pui-kin So, Bin Hu, Z. Yao","doi":"10.5702/massspectrometry.S0028","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0028","url":null,"abstract":"Development of electrospray ionization on solid substrates (solid-substrate ESI) avoids the clogging problem encountered in conventional capillary-based ESI, allows more convenient sampling and permits new applications. So far, solid-substrate ESI with various materials, e.g., metals, paper, wood, fibers and biological tissue, has been developed, and applications ranging from analysis of pure compounds to complex mixtures as well as in vivo study were demonstrated. Particularly, the capability of solid-substrate ESI in direct analysis of complex samples, e.g., biological fluids and foods, has significantly facilitated mass spectrometric analysis in real-life applications and led to increasingly important roles of these techniques nowadays. In this review, various solid-substrate ESI techniques and their applications are summarized and the prospects in this field are discussed.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"127 2 1","pages":"S0028"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77878199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.K0006
Yu-Ju Chen, J. Shiea
The first Asia and Oceania Mass Spectrometry Conference (AOMSC) organized by the Mass Spectrometry Society for Japan (MSSJ) was held in Tsukuba, Japan in 2010. The 2nd and 3rd AOMSC were held in Busan, Korea in 2011 and Kyoto, Japan in 2012; with the conferences organized by the Korean Society for Mass Spectrometry (KSMS) and MSSJ, respectively. The continuous effort on the 4th AOMSC, was hosted and organized by Taiwan Society for Mass Spectrometry (TSMS) in July 10–12, 2013, at the Taipei International Convention Center (TICC), Taiwan. More than 800 participants attended the conference, where they contributed 88 oral and 196 poster presentations and discussed current advances in mass spectrometry regarding fundamentals; instrumentation; methodology; interfacing to chromatographs; and a broad range of applications in emerging fields such as the environmental sciences, energy, food safety, forensics, nanomaterials, molecular imaging, clinic diagnoses, pharmaceuticals, biomedicine, quantitative proteomics, post-translational modifications, metabolomics, glycoproteomics, bioinformatics, and inorganic mass spectrometry.
{"title":"Recent Development of Mass Spectrometric Technologies in Asia and Oceania.","authors":"Yu-Ju Chen, J. Shiea","doi":"10.5702/massspectrometry.K0006","DOIUrl":"https://doi.org/10.5702/massspectrometry.K0006","url":null,"abstract":"The first Asia and Oceania Mass Spectrometry Conference (AOMSC) organized by the Mass Spectrometry Society for Japan (MSSJ) was held in Tsukuba, Japan in 2010. The 2nd and 3rd AOMSC were held in Busan, Korea in 2011 and Kyoto, Japan in 2012; with the conferences organized by the Korean Society for Mass Spectrometry (KSMS) and MSSJ, respectively. The continuous effort on the 4th AOMSC, was hosted and organized by Taiwan Society for Mass Spectrometry (TSMS) in July 10–12, 2013, at the Taipei International Convention Center (TICC), Taiwan. More than 800 participants attended the conference, where they contributed 88 oral and 196 poster presentations and discussed current advances in mass spectrometry regarding fundamentals; instrumentation; methodology; interfacing to chromatographs; and a broad range of applications in emerging fields such as the environmental sciences, energy, food safety, forensics, nanomaterials, molecular imaging, clinic diagnoses, pharmaceuticals, biomedicine, quantitative proteomics, post-translational modifications, metabolomics, glycoproteomics, bioinformatics, and inorganic mass spectrometry.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"161 1","pages":"K0006"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86184008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0025
S. Taira, H. Taguchi, Reiko Fukuda, Kohei Uematsu, Y. Ichiyanagi, Yukie Tanaka, Yutaka Fujii, H. Katano
A specific property of silver oxide-based nanoparticles permits the ionization of an analyte, giving rise to various applications of a smart analytical methodology. The nanoparticles (d=6.7 nm) contained an Ag2O core. The detection of several model componds (a nucleobase and two hair growth promoters) via the use of silver oxide nanoparticles is described. Adducts were produced between the target molecules and the two silver stable isotopes (Ag(107) and Ag(109)), resulting in the formation of specific signals as well as a protonated signal. Thus, it was possible to easily determine whether the given signals were correlated with the target molecule or not.
{"title":"Silver Oxide Based Nanoparticle Assisted Laser Desorption/Ionization Mass Spectrometry for the Detection of Low Molecular Weight Compounds.","authors":"S. Taira, H. Taguchi, Reiko Fukuda, Kohei Uematsu, Y. Ichiyanagi, Yukie Tanaka, Yutaka Fujii, H. Katano","doi":"10.5702/massspectrometry.S0025","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0025","url":null,"abstract":"A specific property of silver oxide-based nanoparticles permits the ionization of an analyte, giving rise to various applications of a smart analytical methodology. The nanoparticles (d=6.7 nm) contained an Ag2O core. The detection of several model componds (a nucleobase and two hair growth promoters) via the use of silver oxide nanoparticles is described. Adducts were produced between the target molecules and the two silver stable isotopes (Ag(107) and Ag(109)), resulting in the formation of specific signals as well as a protonated signal. Thus, it was possible to easily determine whether the given signals were correlated with the target molecule or not.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"7 1","pages":"S0025"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87462026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0030
E. W. Y. Ng, H. S. Lam, P. Ng, T. Poon
Parallel Fragmentation Monitoring (PFM), which is an analogue of selected reaction monitoring (SRM), is a recently developed method for quantification of small molecules by MALDI-TOF/TOF mass spectrometry (MS). It is well known that isobaric interference substances can be occasionally present in complex biological samples, and affect the accuracy of measurement by SRM. Unfortunately, by design it is not possible to assess whether isobaric interference happens in a SRM analysis. In contrast, the unique design of PFM should allow quick inspection for isobaric interference and subsequent correction. In this study, using arginine as an example, interference effect of isobaric structural analogs on the quantification of citrulline by PFM was evaluated. Our results showed that the presence of arginine affected the measured concentrations of citrulline standard solutions in a concentration dependent manner. Such interference could be observed readily in the MS/MS spectra, and contributed by [arginine+H-NH3](+) fragment ion. Because of having highly similar mass, (13)C-isotope of [arginine+H-NH3](+) fragment ion overlapped with monoisotope of [citrulline+H-NH3](+) fragment ion, which was used as the report ion for quantification. However, such interference could be mathematically eliminated or minimized through estimation of the signal intensity of the (13)C-isotopic peak of [arginine+H-NH3](+) from the intensity of the corresponding monoisotopic peak according to isotope distribution of elements. Furthermore, the presence of interfering fragment ions could be avoided by optimizing MALDI ionization condition. In conclusion, isobaric interference can happen in PFM, but can be easily identified in the mass spectra and eliminated (minimized) with simple methods.
{"title":"Study of Isobaric Interference in Quantification of Citrulline by Parallel Fragmentation Monitoring.","authors":"E. W. Y. Ng, H. S. Lam, P. Ng, T. Poon","doi":"10.5702/massspectrometry.S0030","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0030","url":null,"abstract":"Parallel Fragmentation Monitoring (PFM), which is an analogue of selected reaction monitoring (SRM), is a recently developed method for quantification of small molecules by MALDI-TOF/TOF mass spectrometry (MS). It is well known that isobaric interference substances can be occasionally present in complex biological samples, and affect the accuracy of measurement by SRM. Unfortunately, by design it is not possible to assess whether isobaric interference happens in a SRM analysis. In contrast, the unique design of PFM should allow quick inspection for isobaric interference and subsequent correction. In this study, using arginine as an example, interference effect of isobaric structural analogs on the quantification of citrulline by PFM was evaluated. Our results showed that the presence of arginine affected the measured concentrations of citrulline standard solutions in a concentration dependent manner. Such interference could be observed readily in the MS/MS spectra, and contributed by [arginine+H-NH3](+) fragment ion. Because of having highly similar mass, (13)C-isotope of [arginine+H-NH3](+) fragment ion overlapped with monoisotope of [citrulline+H-NH3](+) fragment ion, which was used as the report ion for quantification. However, such interference could be mathematically eliminated or minimized through estimation of the signal intensity of the (13)C-isotopic peak of [arginine+H-NH3](+) from the intensity of the corresponding monoisotopic peak according to isotope distribution of elements. Furthermore, the presence of interfering fragment ions could be avoided by optimizing MALDI ionization condition. In conclusion, isobaric interference can happen in PFM, but can be easily identified in the mass spectra and eliminated (minimized) with simple methods.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"224 1","pages":"S0030"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79070666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0029
S. Shimma, Y. Sugiura
Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) can be used to visualize the distribution of biomolecules (proteins, peptides, metabolites) and drugs on tissue surfaces. In MALDI-IMS, sample preparation is crucial for successful results. A variety of conditions, such as tissue sampling methods, tissue thickness and matrix application procedure can have an impact on the results. In this review, we summarize each sample preparation step in an orderly sequence with practical examples. In addition, we discuss the importance of the organic solvent used in the matrix solution. The composition of the organic solvent used in the matrix solution is critical for achieving a high sensitivity in this procedure.
{"title":"Effective Sample Preparations in Imaging Mass Spectrometry.","authors":"S. Shimma, Y. Sugiura","doi":"10.5702/massspectrometry.S0029","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0029","url":null,"abstract":"Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) can be used to visualize the distribution of biomolecules (proteins, peptides, metabolites) and drugs on tissue surfaces. In MALDI-IMS, sample preparation is crucial for successful results. A variety of conditions, such as tissue sampling methods, tissue thickness and matrix application procedure can have an impact on the results. In this review, we summarize each sample preparation step in an orderly sequence with practical examples. In addition, we discuss the importance of the organic solvent used in the matrix solution. The composition of the organic solvent used in the matrix solution is critical for achieving a high sensitivity in this procedure.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"103 1","pages":"S0029"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88964062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0032
K. Gillig, Chung-Hsuan Chen
Ion mobility spectrometry (IMS) as a stand-alone technique has become increasingly important for applications in security, defense, and environmental monitoring, and also in biological applications such as molecular structure and -omic analysis when combined with mass spectrometry. Yet, the majority of these devices are drift cell based and limited by low duty cycles because of ion gating. Differential Mobility Analyzers (DMAs) are attractive alternatives due to their continuous ion transmission and success in analyzing aerosol particles in real time environmental tests. But, the resolution of a DMA is low due to difficulties in achieving laminar gas flow, low sample gas flow to sheath gas flow ratio, and high velocity sheath gas using small pumps, if portability is a concern. To overcome these challenges, we will introduce a new ion mobility spectrometer that increases the amount of work done on the ions during separation by introducing an electric field opposing the gas flow direction while simultaneously preserving laminar gas flow. The development of the Periodic Focusing Differential Mobility Analyzer (PFDMA) can lead to a portable device that exhibits both high resolution and sensitivity, to meet the needs of today's expanding applications.
{"title":"Increasing the Performance of Portable Ion Mobility Analyzers: Development of the Periodic Focusing Differential Mobility Analyzer (PFDMA).","authors":"K. Gillig, Chung-Hsuan Chen","doi":"10.5702/massspectrometry.S0032","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0032","url":null,"abstract":"Ion mobility spectrometry (IMS) as a stand-alone technique has become increasingly important for applications in security, defense, and environmental monitoring, and also in biological applications such as molecular structure and -omic analysis when combined with mass spectrometry. Yet, the majority of these devices are drift cell based and limited by low duty cycles because of ion gating. Differential Mobility Analyzers (DMAs) are attractive alternatives due to their continuous ion transmission and success in analyzing aerosol particles in real time environmental tests. But, the resolution of a DMA is low due to difficulties in achieving laminar gas flow, low sample gas flow to sheath gas flow ratio, and high velocity sheath gas using small pumps, if portability is a concern. To overcome these challenges, we will introduce a new ion mobility spectrometer that increases the amount of work done on the ions during separation by introducing an electric field opposing the gas flow direction while simultaneously preserving laminar gas flow. The development of the Periodic Focusing Differential Mobility Analyzer (PFDMA) can lead to a portable device that exhibits both high resolution and sensitivity, to meet the needs of today's expanding applications.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"7 1","pages":"S0032"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83901503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.5702/massspectrometry.S0024
L. Chen, Md Matiur Rahman, K. Hiraoka
Pressurizing the ionization source to gas pressure greater than atmospheric pressure is a new tactic aimed at further improving the performance of atmospheric pressure ionization (API) sources. In principle, all API sources, such as ESI, APCI and AP-MALDI, can be operated at pressure higher than 1 atm if suitable vacuum interface is available. The gas pressure in the ion source can have different role for different ionization. For example, in the case of ESI, stable electrospray could be sustained for high surface tension liquid (e.g., pure water) under super-atmospheric pressure, owing to the absence of electric discharge. Even for nanoESI, which is known to work well with aqueous solution, its stability and sensitivity were found to be enhanced, particularly in the negative mode when the ion source was pressurized. For the gas phase ionization like APCI, measurement of gaseous compound also showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. The enhancement was due to the increased collision frequency among reactant ion and analyte that promoted the ion/molecule reaction and a higher intake rate of gas to the mass spectrometer. Because the design of vacuum interface for API instrument is based on the upstream pressure of 1 atm, some coupling aspects need to be considered when connecting the high pressure ion source to the mass spectrometer. Several coupling strategies are discussed in this paper.
{"title":"Super-Atmospheric Pressure Ion Sources: Application and Coupling to API Mass Spectrometer.","authors":"L. Chen, Md Matiur Rahman, K. Hiraoka","doi":"10.5702/massspectrometry.S0024","DOIUrl":"https://doi.org/10.5702/massspectrometry.S0024","url":null,"abstract":"Pressurizing the ionization source to gas pressure greater than atmospheric pressure is a new tactic aimed at further improving the performance of atmospheric pressure ionization (API) sources. In principle, all API sources, such as ESI, APCI and AP-MALDI, can be operated at pressure higher than 1 atm if suitable vacuum interface is available. The gas pressure in the ion source can have different role for different ionization. For example, in the case of ESI, stable electrospray could be sustained for high surface tension liquid (e.g., pure water) under super-atmospheric pressure, owing to the absence of electric discharge. Even for nanoESI, which is known to work well with aqueous solution, its stability and sensitivity were found to be enhanced, particularly in the negative mode when the ion source was pressurized. For the gas phase ionization like APCI, measurement of gaseous compound also showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. The enhancement was due to the increased collision frequency among reactant ion and analyte that promoted the ion/molecule reaction and a higher intake rate of gas to the mass spectrometer. Because the design of vacuum interface for API instrument is based on the upstream pressure of 1 atm, some coupling aspects need to be considered when connecting the high pressure ion source to the mass spectrometer. Several coupling strategies are discussed in this paper.","PeriodicalId":18243,"journal":{"name":"Mass spectrometry","volume":"16 1","pages":"S0024"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73784713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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