Pub Date : 2025-07-18DOI: 10.1016/j.ijms.2025.117494
L. Torrisi , A. Torrisi , M. Cutroneo
Graphene oxide (GO) foils were irradiated in high vacuum using an ns pulsed laser operating at 1064 nm and different fluences. Laser irradiation generates plasma and promotes the emission of carbon atoms and molecules, functional groups of oxygen, and absorbed gases, generating a surface GO reduction. The emitted particles have been monitored through a high-sensitivity mass quadrupole spectrometer operating between 1 amu and 300 amu.
The produced laser irradiation was investigated using low fluences, as well as the generated plasma.
The pristine and laser-irradiated GO were analyzed using different analysis techniques: Optical spectroscopy, time-of-flight measurements and mass spectrometry. The results obtained in previous experiments using other types of analyses were also cited.
Results demonstrated that under laser-irradiation graphene oxide loses different functional groups of oxygen becoming richer in sp2 hybridized carbon content, enhancing its carbon content, and becoming more electrically conductive.
{"title":"Mass spectrometry of laser reduced graphene oxide in vacuum","authors":"L. Torrisi , A. Torrisi , M. Cutroneo","doi":"10.1016/j.ijms.2025.117494","DOIUrl":"10.1016/j.ijms.2025.117494","url":null,"abstract":"<div><div>Graphene oxide (GO) foils were irradiated in high vacuum using an <em>ns</em> pulsed laser operating at 1064 nm and different fluences. Laser irradiation generates plasma and promotes the emission of carbon atoms and molecules, functional groups of oxygen, and absorbed gases, generating a surface GO reduction. The emitted particles have been monitored through a high-sensitivity mass quadrupole spectrometer operating between 1 amu and 300 amu.</div><div>The produced laser irradiation was investigated using low fluences, as well as the generated plasma.</div><div>The pristine and laser-irradiated GO were analyzed using different analysis techniques: Optical spectroscopy, time-of-flight measurements and mass spectrometry. The results obtained in previous experiments using other types of analyses were also cited.</div><div>Results demonstrated that under laser-irradiation graphene oxide loses different functional groups of oxygen becoming richer in sp<sup>2</sup> hybridized carbon content, enhancing its carbon content, and becoming more electrically conductive.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"516 ","pages":"Article 117494"},"PeriodicalIF":1.6,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-08DOI: 10.1016/j.ijms.2025.117493
Chenxin Ye , Xinyao Wang , Junliang Zhang , Boping Li , Jiancheng Yu
This study experimentally investigates the properties of low-pressure dielectric barrier discharge (DBD) plasma. A ring-ring DBD configuration was employed. Spectroscopic and electrical measurements were conducted at varying gas pressures to characterize the plasma properties. The results revealed that the luminous region of the plasma expands and exhibits maximum luminescence near 600 Pa, with a subsequent contraction and intensity diminution at lower pressures. Analysis of emission spectra identified nitrogen's second positive system (SPS) and first negative system (FNS) as the primary contributors. The highest density of excited molecule and excited ion are at 660 Pa and 100 Pa, respectively. Mass spectrometry measurements indicate that the excited state has the ability to undergo Penning ionization. This study provides the variation of excited molecules and ions with pressure in low-pressure dielectric barrier discharge, which can be used for the optimization of ionization source and the analysis of mass spectrometry data.
{"title":"Experimental studies on low-pressure air dielectric barrier discharge plasma for ionization source","authors":"Chenxin Ye , Xinyao Wang , Junliang Zhang , Boping Li , Jiancheng Yu","doi":"10.1016/j.ijms.2025.117493","DOIUrl":"10.1016/j.ijms.2025.117493","url":null,"abstract":"<div><div>This study experimentally investigates the properties of low-pressure dielectric barrier discharge (DBD) plasma. A ring-ring DBD configuration was employed. Spectroscopic and electrical measurements were conducted at varying gas pressures to characterize the plasma properties. The results revealed that the luminous region of the plasma expands and exhibits maximum luminescence near 600 Pa, with a subsequent contraction and intensity diminution at lower pressures. Analysis of emission spectra identified nitrogen's second positive system (SPS) and first negative system (FNS) as the primary contributors. The highest density of excited molecule <span><math><mrow><msub><mi>N</mi><mn>2</mn></msub><mrow><mo>(</mo><mrow><msup><mi>C</mi><mn>3</mn></msup><msub><mi>Π</mi><mi>u</mi></msub></mrow><mo>)</mo></mrow></mrow></math></span> and excited ion <span><math><mrow><msubsup><mi>N</mi><mn>2</mn><mo>+</mo></msubsup><mrow><mo>(</mo><mrow><msup><mi>B</mi><mn>2</mn></msup><msubsup><mi>Σ</mi><mi>u</mi><mo>+</mo></msubsup></mrow><mo>)</mo></mrow></mrow></math></span> are at 660 Pa and 100 Pa, respectively. Mass spectrometry measurements indicate that the excited state <span><math><mrow><msub><mi>N</mi><mn>2</mn></msub><mrow><mo>(</mo><mrow><msup><mi>C</mi><mn>3</mn></msup><msub><mi>Π</mi><mi>u</mi></msub></mrow><mo>)</mo></mrow></mrow></math></span> has the ability to undergo Penning ionization. This study provides the variation of excited molecules and ions with pressure in low-pressure dielectric barrier discharge, which can be used for the optimization of ionization source and the analysis of mass spectrometry data.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"516 ","pages":"Article 117493"},"PeriodicalIF":1.6,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-28DOI: 10.1016/j.ijms.2025.117485
Binrui Xie , Yanbing Li , Nan Zhang , Chuangui Zhou , Jiexun Bu , Lun Wu , Jun Zhu , Wenzhuo Wang , Lei Liu , Ming Li
In this study, an innovative approach combining Machine Learning (ML) with Ensemble Empirical Mode Decomposition (EEMD) was proposed to predict lamotrigine concentrations in actual samples, improving detection performance in complex matrices. EEMD decomposed the mass spectrometry data to extract Intrinsic Mode Functions (IMFs), enabling separation of noise from key signal features. Ridge Regression (RR) addressed multicollinearity among high-dimensional IMF features and enhanced model generalization via L2 regularization. ML was further applied to optimize the key EEMD parameter (ensemble number K),thereby improving both decomposition quality and prediction accuracy. Experimental validation showed that the method achieved over 90 % prediction accuracy in three types of blind samples (PBS, rabbit blood, and human matrix), with improved Relative Standard Deviation (RSD). These results confirm the method’s precision and robustness in diverse biological matrices. Compared to traditional techniques, the proposed approach delivers marked improvements in both accuracy and stability, can supporting more reliable drug concentration monitoring for clinical applications.
{"title":"An adaptive EEMD-machine learning algorithm for multi-matrix drug concentration prediction using miniature mass spectrometry","authors":"Binrui Xie , Yanbing Li , Nan Zhang , Chuangui Zhou , Jiexun Bu , Lun Wu , Jun Zhu , Wenzhuo Wang , Lei Liu , Ming Li","doi":"10.1016/j.ijms.2025.117485","DOIUrl":"10.1016/j.ijms.2025.117485","url":null,"abstract":"<div><div>In this study, an innovative approach combining Machine Learning (ML) with Ensemble Empirical Mode Decomposition (EEMD) was proposed to predict lamotrigine concentrations in actual samples, improving detection performance in complex matrices. EEMD decomposed the mass spectrometry data to extract Intrinsic Mode Functions (IMFs), enabling separation of noise from key signal features. Ridge Regression (RR) addressed multicollinearity among high-dimensional IMF features and enhanced model generalization via L2 regularization. ML was further applied to optimize the key EEMD parameter (ensemble number K),thereby improving both decomposition quality and prediction accuracy. Experimental validation showed that the method achieved over 90 % prediction accuracy in three types of blind samples (PBS, rabbit blood, and human matrix), with improved Relative Standard Deviation (RSD). These results confirm the method’s precision and robustness in diverse biological matrices. Compared to traditional techniques, the proposed approach delivers marked improvements in both accuracy and stability, can supporting more reliable drug concentration monitoring for clinical applications.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"516 ","pages":"Article 117485"},"PeriodicalIF":1.6,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-18DOI: 10.1016/j.ijms.2025.117484
Luke MacAleese , Xavier Dagany , Lény Garcia , Jérôme Lemoine , Philippe Dugourd , Marion Girod
An analytical method is demonstrated which allows to follow a data independent, all ion fragmentation (AIF) acquisition procedure, but to fall back on a standard and generic data-dependent acquisition (DDA) analysis procedure for the data treatment: searching databases with individual precursor ions and fragments lists. This method is implemented with photo-activation (LID) in the visible range which allows extreme specificity and sensitivity, and is demonstrated on Cysteine-containing tryptic peptides grafted with a chromophore. This proof of concept relies on the efficient implementation of LID directly in the C-trap of a ThermoScientific QExactive mass spectrometer during ion accumulation, before full MS detection. Laser irradiation turned alternatively ON and OFF after each full MS allows to build differential mass spectra in which non-dissociating ions are cancelled out while fragmenting precursors and fragments show up with opposite signs, which enables to build precursor/fragments lists for database search. Protein identification was demonstrated with remarkably low false discovery rates. Relative quantification was also demonstrated by integration of precursor and fragment ion elution peaks after differential analysis and limits of quantifications were demonstrated down to 11 ng of proteins injected. This mixed approach takes the best of both worlds – the deep proteome coverage of DIA, with the exhaustive fragmentation of all precursor ions, and the reliability and ease of use of classical DDA database search, relieving the need for the initial constitution of a spectral library.
{"title":"All-ions laser induced dissociation (AI-LID) in the C-trap of a Q Exactive: Data independent identification and quantification directly from ultra-high resolution differential mass spectra","authors":"Luke MacAleese , Xavier Dagany , Lény Garcia , Jérôme Lemoine , Philippe Dugourd , Marion Girod","doi":"10.1016/j.ijms.2025.117484","DOIUrl":"10.1016/j.ijms.2025.117484","url":null,"abstract":"<div><div>An analytical method is demonstrated which allows to follow a data independent, all ion fragmentation (AIF) acquisition procedure, but to fall back on a standard and generic data-dependent acquisition (DDA) analysis procedure for the data treatment: searching databases with individual precursor ions and fragments lists. This method is implemented with photo-activation (LID) in the visible range which allows extreme specificity and sensitivity, and is demonstrated on Cysteine-containing tryptic peptides grafted with a chromophore. This proof of concept relies on the efficient implementation of LID directly in the C-trap of a ThermoScientific QExactive mass spectrometer during ion accumulation, before full MS detection. Laser irradiation turned alternatively ON and OFF after each full MS allows to build differential mass spectra in which non-dissociating ions are cancelled out while fragmenting precursors and fragments show up with opposite signs, which enables to build precursor/fragments lists for database search. Protein identification was demonstrated with remarkably low false discovery rates. Relative quantification was also demonstrated by integration of precursor and fragment ion elution peaks after differential analysis and limits of quantifications were demonstrated down to 11 ng of proteins injected. This mixed approach takes the best of both worlds – the deep proteome coverage of DIA, with the exhaustive fragmentation of all precursor ions, and the reliability and ease of use of classical DDA database search, relieving the need for the initial constitution of a spectral library.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"515 ","pages":"Article 117484"},"PeriodicalIF":1.6,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144335901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-16DOI: 10.1016/j.ijms.2025.117483
Jing Yu , Sven Heiles
Sphingolipids are essential building blocks of most organisms. The structure of sphingolipids is tightly regulated and dysregulation during diseases can result in altered sphingolipid structures. In this manuscript, we explore the potential of sphingolipid epoxidation for the assignment and discrimination of sphingolipid structures. Employing shotgun tandem mass spectrometry, liquid chromatography tandem mass spectrometry, authentic sphingolipid standards, and density function theory, we demonstrate that epoxidation of shingoid bases (SPBs), ceramides, and sphingomyelins facilitates C=C bond (DB) position assignment. This includes DBs in the N-linked fatty acyl moiety and the sphingoid base. For SPBs with DBs at position 4, a major component for almost all sphingolipids, we furthermore demonstrate that the fragmentation pathway differs for this DB position compared to other DB-diagnostic fragment ions. We show that epoxidation of this DB position facilities intramolecular rearrangement and formation of distinct diagnostic fragment ions. To demonstrate the analytical capabilities and show that the 4 SPB DBs enable confident differentiation of ceramides and dihydroceramides, results for brain ceramide extract are presented. The identified fragmentation pathway for 4 SPB DB ions in combination with N-acyl assignment and DB position assignment allows to annotate 25 ceramide/dihydroceramide compounds in the brain ceramide extract out of which 23 are DB position isomers.
{"title":"Structure selective fragment ions of epoxidized sphingolipids","authors":"Jing Yu , Sven Heiles","doi":"10.1016/j.ijms.2025.117483","DOIUrl":"10.1016/j.ijms.2025.117483","url":null,"abstract":"<div><div>Sphingolipids are essential building blocks of most organisms. The structure of sphingolipids is tightly regulated and dysregulation during diseases can result in altered sphingolipid structures. In this manuscript, we explore the potential of sphingolipid epoxidation for the assignment and discrimination of sphingolipid structures. Employing shotgun tandem mass spectrometry, liquid chromatography tandem mass spectrometry, authentic sphingolipid standards, and density function theory, we demonstrate that epoxidation of shingoid bases (SPBs), ceramides, and sphingomyelins facilitates C=C bond (DB) position assignment. This includes DBs in the N-linked fatty acyl moiety and the sphingoid base. For SPBs with DBs at position 4, a major component for almost all sphingolipids, we furthermore demonstrate that the fragmentation pathway differs for this DB position compared to other DB-diagnostic fragment ions. We show that epoxidation of this DB position facilities intramolecular rearrangement and formation of distinct diagnostic fragment ions. To demonstrate the analytical capabilities and show that the 4 SPB DBs enable confident differentiation of ceramides and dihydroceramides, results for brain ceramide extract are presented. The identified fragmentation pathway for 4 SPB DB ions in combination with N-acyl assignment and DB position assignment allows to annotate 25 ceramide/dihydroceramide compounds in the brain ceramide extract out of which 23 are DB position isomers.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"515 ","pages":"Article 117483"},"PeriodicalIF":1.6,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-06DOI: 10.1016/j.ijms.2025.117473
Camille Guitteny , Simon Ollivier , Oznur Yeni , Mathis Ralaivao , Mathieu Fanuel , Joël Boustie , Isabelle Compagnon , Vincent Ferrières , Solenn Ferron , Hélène Rogniaux , David Ropartz , Laurent Legentil , Françoise Le Dévéhat
MALDI-TOF MS methods coupled with offline chromatographic data were used to compare the distribution of oligosaccharides generated from acidic or oxidative degradation (Fitdog) of high molecular weight polysaccharides (>10 kDa) obtained from two lichens Lasallia pustulata and Cetraria islandica. MALDI allowed to quickly compare the kinetics of degradation on both models (starting from non-purified polysaccharides) and to evaluate the dispersity of the resulting oligosaccharides. MALDI-MS confirmed on one hand that TFA hydrolysis gave neutral oligosaccharides easy to correlate with the chemical formula. On the other hand, more structural diversity was evidenced using the Fitdog protocol. Deep analysis of the MALDI data highlighted the formation of by-products corresponding to modified oligosaccharides (e.g., intracyclic cleavages).
{"title":"MALDI-TOF-MS unveils the distribution of oligosaccharides produced by hydrolysis of lichen polysaccharides through acidic and oxidative methods – a comparative study","authors":"Camille Guitteny , Simon Ollivier , Oznur Yeni , Mathis Ralaivao , Mathieu Fanuel , Joël Boustie , Isabelle Compagnon , Vincent Ferrières , Solenn Ferron , Hélène Rogniaux , David Ropartz , Laurent Legentil , Françoise Le Dévéhat","doi":"10.1016/j.ijms.2025.117473","DOIUrl":"10.1016/j.ijms.2025.117473","url":null,"abstract":"<div><div>MALDI-TOF MS methods coupled with offline chromatographic data were used to compare the distribution of oligosaccharides generated from acidic or oxidative degradation (Fitdog) of high molecular weight polysaccharides (>10 kDa) obtained from two lichens <em>Lasallia pustulata</em> and <em>Cetraria islandica</em>. MALDI allowed to quickly compare the kinetics of degradation on both models (starting from non-purified polysaccharides) and to evaluate the dispersity of the resulting oligosaccharides. MALDI-MS confirmed on one hand that TFA hydrolysis gave neutral oligosaccharides easy to correlate with the chemical formula. On the other hand, more structural diversity was evidenced using the Fitdog protocol. Deep analysis of the MALDI data highlighted the formation of by-products corresponding to modified oligosaccharides (e.g., intracyclic cleavages).</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"515 ","pages":"Article 117473"},"PeriodicalIF":1.6,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-05DOI: 10.1016/j.ijms.2025.117475
Hanzhi Zhang , Xiakun Wang , Bin Xu , Zhenhua Tian , Yu Luo , Zhijun Tang , Wen Liu
Herein, the structures of echinocandins were analyzed by high-performance liquid chromatography-quadrupole/time-of-flight-tandem mass spectrometry (HPLC-Q/TOF-MS/MS). The echinocandin components were separated by using a Diamonsil Plus C18 column (5 μm, 4.6 mm × 250 mm), with 0.1 % formic acid in water as mobile phase A and 0.1 % formic acid in acetonitrile as mobile phase B under gradient elution. A systematic strategy for the structural characterization of echinocandin B, which is the main component of echicandins, is presented based on the accurate molecular mass and diagnostic ions obtained from both adduct ions [M+H]+ and [M+Na]+ as precursor ions. In the three fragmentation pathways obtained from the precursor ion of [M+H]+, echinocandins and its fragment ions produced continuous dehydrated ions ([M-nH2O + H]+, n = 1, 2, 3, 4). The N-terminal fatty acyl (FA) connecting to the ornithine derivative transferred to the amino group of the proline derivative during fragmentation. Different characteristic ions, depending on the number of hydroxyls (0, 1, 2) on the ornithine derivative of different echinocandin analog. Moreover, the threonine residues underwent the neutral consecutive loss of acetaldehyde from the [M+Na]+ precursor ion. The [M+H]+ and [M+Na]+ echinocandin precursor ions respectively lost 1-(4-hydroxyphenyl)ethane-1,2-diol and 2-hydroxy-2-(4-hydroxyphenyl)acetaldehyde from the homotyrosine residues to generate different fragmentation ions. Thirteen echinocandin analogs were identified, including echinocandin C, echinocandin D, and echinocandin B variants with different FA and amino acid compositions.
采用高效液相色谱-四极杆/飞行时间串联质谱（HPLC-Q/TOF-MS/MS）分析棘白菌素的结构。采用Diamonsil Plus C18色谱柱（5 μm, 4.6 mm × 250 mm），以0.1%甲酸水溶液为流动相a， 0.1%甲酸乙腈为流动相B，梯度洗脱分离棘白菌素。本文基于[M+H]+和[M+Na]+加合离子作为前体离子获得准确的分子质量和诊断离子，提出了一种系统的表征棘白素B结构的策略。在由[M+H]+前体离子得到的3条破碎途径中，棘白菌素及其碎片离子产生连续的脱水离子（[M- nh2o +H]+, n = 1,2,3,4）。连接鸟氨酸衍生物的n端脂肪酰基（FA）在断裂过程中转移到脯氨酸衍生物的氨基上。不同的特征离子，取决于羟基（0、1、2）的数目对不同棘白素类似物的鸟氨酸衍生物。此外，苏氨酸残基经历了[M+Na]+前体离子乙醛的中性连续损失。[M+H]+和[M+Na]+棘白菌素前体离子分别从同型酪氨酸残基中失去1-（4-羟基苯基）乙烷-1,2-二醇和2-羟基-2-（4-羟基苯基）乙醛，生成不同的断裂离子。鉴定出13种棘白菌素类似物，包括棘白菌素C、棘白菌素D和棘白菌素B，它们具有不同的FA和氨基酸组成。
{"title":"Structural analysis of echinocandins via high-performance liquid chromatography-quadrupole/time-of-flight-tandem mass spectrometry","authors":"Hanzhi Zhang , Xiakun Wang , Bin Xu , Zhenhua Tian , Yu Luo , Zhijun Tang , Wen Liu","doi":"10.1016/j.ijms.2025.117475","DOIUrl":"10.1016/j.ijms.2025.117475","url":null,"abstract":"<div><div>Herein, the structures of echinocandins were analyzed by high-performance liquid chromatography-quadrupole/time-of-flight-tandem mass spectrometry (HPLC-Q/TOF-MS/MS). The echinocandin components were separated by using a Diamonsil Plus C18 column (5 μm, 4.6 mm × 250 mm), with 0.1 % formic acid in water as mobile phase A and 0.1 % formic acid in acetonitrile as mobile phase B under gradient elution. A systematic strategy for the structural characterization of echinocandin B, which is the main component of echicandins, is presented based on the accurate molecular mass and diagnostic ions obtained from both adduct ions [M+H]<sup>+</sup> and [M+Na]<sup>+</sup> as precursor ions. In the three fragmentation pathways obtained from the precursor ion of [M+H]<sup>+</sup>, echinocandins and its fragment ions produced continuous dehydrated ions ([M-<em>n</em>H<sub>2</sub>O + H]<sup>+</sup>, <em>n</em> = 1, 2, 3, 4). The <em>N</em>-terminal fatty acyl (FA) connecting to the ornithine derivative transferred to the amino group of the proline derivative during fragmentation. Different characteristic ions, depending on the number of hydroxyls (0, 1, 2) on the ornithine derivative of different echinocandin analog. Moreover, the threonine residues underwent the neutral consecutive loss of acetaldehyde from the [M+Na]<sup>+</sup> precursor ion. The [M+H]<sup>+</sup> and [M+Na]<sup>+</sup> echinocandin precursor ions respectively lost 1-(4-hydroxyphenyl)ethane-1,2-diol and 2-hydroxy-2-(4-hydroxyphenyl)acetaldehyde from the homotyrosine residues to generate different fragmentation ions. Thirteen echinocandin analogs were identified, including echinocandin C, echinocandin D, and echinocandin B variants with different FA and amino acid compositions.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"515 ","pages":"Article 117475"},"PeriodicalIF":1.6,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144243010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-04DOI: 10.1016/j.ijms.2025.117482
Thanh D. Do
Advancing our understanding of biomolecular systems requires technologies that can unravel their intricate dynamics and structures. Mass spectrometry (MS) has emerged as a versatile technique for characterizing complex systems, yet its findings are most impactful when paired with structural methods such as NMR, X-ray crystallography, and microscopy. This Perspective examines how ion mobility-mass spectrometry (IM-MS) serves as a key connector between dynamic molecular behavior and high-resolution structural insights. Examples from recent research in our laboratory illustrate how IM-MS enhances the study of flexible peptides, transient protein assemblies, and metabolite aggregation. These studies highlight the method's ability to reveal properties inaccessible to single techniques. By integrating multiple approaches, researchers gain a more comprehensive view of biomolecular complexity, demonstrating the power of combining analytical methods to tackle open questions in structural biology. This approach reflects the collaborative and iterative nature of science, where diverse perspectives converge to deepen our understanding of the molecular world.
{"title":"Structural ion mobility spectrometry: What can we really measure?","authors":"Thanh D. Do","doi":"10.1016/j.ijms.2025.117482","DOIUrl":"10.1016/j.ijms.2025.117482","url":null,"abstract":"<div><div>Advancing our understanding of biomolecular systems requires technologies that can unravel their intricate dynamics and structures. Mass spectrometry (MS) has emerged as a versatile technique for characterizing complex systems, yet its findings are most impactful when paired with structural methods such as NMR, X-ray crystallography, and microscopy. This Perspective examines how ion mobility-mass spectrometry (IM-MS) serves as a key connector between dynamic molecular behavior and high-resolution structural insights. Examples from recent research in our laboratory illustrate how IM-MS enhances the study of flexible peptides, transient protein assemblies, and metabolite aggregation. These studies highlight the method's ability to reveal properties inaccessible to single techniques. By integrating multiple approaches, researchers gain a more comprehensive view of biomolecular complexity, demonstrating the power of combining analytical methods to tackle open questions in structural biology. This approach reflects the collaborative and iterative nature of science, where diverse perspectives converge to deepen our understanding of the molecular world.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"515 ","pages":"Article 117482"},"PeriodicalIF":1.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-31DOI: 10.1016/j.ijms.2025.117474
VarunK. Yadav , R.K. Bhatia , A. Singh , A.M. Kasbeker , M.M. Gulhane , E. Ravisankar , T.K. Saha
The present work deals with the design and development of an efficient cavity ion source (CIS). The design optimization of CIS was carried out on the basis of experimental studies using an indigenous quadrupole mass analyser (QMA). Subsequently, the optimally designed CIS was characterized for the quantitative and qualitative detection of various rare earth and actinide elements. Sensitivity measurement was carried out using total evaporation technique. Same set of studies were also conducted on a conventional thermal ion source (TIS) to compare the performance of the CIS with conventional TIS. The CIS showed an improvement in respective sensitivity by a factor of about 7 and 4 times for Uranium and Strontium as compared to conventional TIS. The improved sensitivity of CIS is attributed to the multiple interactions of the analyte species with the inner surface of the high temperature cavity tube thereby increasing its ionization probability.
{"title":"Development of a high efficiency cavity ion source and its characterization using a quadrupole mass analyser","authors":"VarunK. Yadav , R.K. Bhatia , A. Singh , A.M. Kasbeker , M.M. Gulhane , E. Ravisankar , T.K. Saha","doi":"10.1016/j.ijms.2025.117474","DOIUrl":"10.1016/j.ijms.2025.117474","url":null,"abstract":"<div><div>The present work deals with the design and development of an efficient cavity ion source (CIS). The design optimization of CIS was carried out on the basis of experimental studies using an indigenous quadrupole mass analyser (QMA). Subsequently, the optimally designed CIS was characterized for the quantitative and qualitative detection of various rare earth and actinide elements. Sensitivity measurement was carried out using total evaporation technique. Same set of studies were also conducted on a conventional thermal ion source (TIS) to compare the performance of the CIS with conventional TIS. The CIS showed an improvement in respective sensitivity by a factor of about 7 and 4 times for Uranium and Strontium as compared to conventional TIS. The improved sensitivity of CIS is attributed to the multiple interactions of the analyte species with the inner surface of the high temperature cavity tube thereby increasing its ionization probability.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"515 ","pages":"Article 117474"},"PeriodicalIF":1.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-21DOI: 10.1016/j.ijms.2025.117471
Zejie Fei, Min Ge, Yuan Qian, Hongtao Liu, Yuanyuan Tang
The aim of this study was to propose the decomposition mechanism of heat transfer salt (HTS or Hitec salt) using a high-temperature furnace coupled with a time-of-flight mass spectrometer (TOF-MS). The decomposition process was systematically investigated in a vacuum environment at temperatures of 45 °C, 80 °C, 150 °C, 200 °C, 220 °C and 280 °C. The thermal decomposition of HTS initiated at and above 200 °C, which was slightly higher than its melting point of 142 °C. The main products resulting from the thermochemical reactions of nitrate/nitrite were NO and N2 respectively, followed by N2O. These findings revealed an unconventional reaction pathways for HTS decompositions as it contradicted the common assumption that O2 or NO2 would be present during this process. These new evidences further support the existence of intermediate species, such as superoxide and peroxide ions, in the molten salts during the initial thermal-chemical reaction process involving nitrite/nitrate salts.
{"title":"An in situ analysis of the components of HTS vapor using a home-made high-temperature time-of-flight mass spectrometer","authors":"Zejie Fei, Min Ge, Yuan Qian, Hongtao Liu, Yuanyuan Tang","doi":"10.1016/j.ijms.2025.117471","DOIUrl":"10.1016/j.ijms.2025.117471","url":null,"abstract":"<div><div>The aim of this study was to propose the decomposition mechanism of heat transfer salt (HTS or Hitec salt) using a high-temperature furnace coupled with a time-of-flight mass spectrometer (TOF-MS). The decomposition process was systematically investigated in a vacuum environment at temperatures of 45 °C, 80 °C, 150 °C, 200 °C, 220 °C and 280 °C. The thermal decomposition of HTS initiated at and above 200 °C, which was slightly higher than its melting point of 142 °C. The main products resulting from the thermochemical reactions of nitrate/nitrite were NO and N<sub>2</sub> respectively, followed by N<sub>2</sub>O. These findings revealed an unconventional reaction pathways for HTS decompositions as it contradicted the common assumption that O<sub>2</sub> or NO<sub>2</sub> would be present during this process. These new evidences further support the existence of intermediate species, such as superoxide and peroxide ions, in the molten salts during the initial thermal-chemical reaction process involving nitrite/nitrate salts.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"514 ","pages":"Article 117471"},"PeriodicalIF":1.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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