Pub Date : 2025-12-24DOI: 10.1016/j.ijms.2025.117565
László Rinyu , Andrea Czébely , Diána Kiss , Sándor Kele , Sándor Czellár , József Molnár , Marianna Túri
Clumped isotope thermometry is a robust technique for reconstructing carbonate formation temperatures; however its analytical precision is highly dependent on instrumental stability. In this study, we address the challenge of achieving long-term Δ47 repeatability using a Thermo Scientific™ 253 Plus 10 kV isotope ratio mass spectrometer (IRMS) coupled to a Kiel IV automated carbonate preparation device. The IRMS is equipped with 1013 Ω resistors on high-gain Faraday cups. To minimize the impact of daily laboratory temperature fluctuations, we developed and implemented a prototype Peltier-based cooling system for the amplifier housing.
The combined approach reduced long-term Δ47 standard deviation from 40 to 45 ppm (occasionally reaching up to 60 ppm under extreme conditions) to around 32 ppm. Validation was performed using international carbonate standards and natural travertine samples with known formation temperatures (10–95 °C), and results were bench-marked against previously published data. These improvements demonstrate a practical pathway towards achieving high-precision clumped isotope measurements under variable environmental conditions, and they provide a reproducible methodology for laboratories operating similar instrumentation in comparable settings.
块状同位素测温是重建碳酸盐地层温度的可靠技术；然而，其分析精度高度依赖于仪器的稳定性。在这项研究中，我们使用Thermo Scientific™253 Plus 10 kV同位素比质谱仪（IRMS）与Kiel IV自动碳酸盐制备装置相结合，解决了实现长期Δ47重复性的挑战。IRMS在高增益法拉第杯上配备了1013个Ω电阻。为了尽量减少日常实验室温度波动的影响，我们为放大器外壳开发并实施了一个基于peltier的原型冷却系统。综合方法将长期Δ47标准偏差从40到45 ppm（在极端条件下偶尔达到60 ppm）降低到32 ppm左右。使用国际碳酸盐标准和已知地层温度（10-95℃）的天然石灰华样品进行验证，并根据先前发表的数据对结果进行基准测试。这些改进表明了在可变环境条件下实现高精度团块同位素测量的可行途径，并为在可比环境下操作类似仪器的实验室提供了可重复的方法。
{"title":"Improving long-term Δ47 repeatability of the Thermo Scientific 253 Plus 10 kV IRMS using a prototype Peltier-based cooling system","authors":"László Rinyu , Andrea Czébely , Diána Kiss , Sándor Kele , Sándor Czellár , József Molnár , Marianna Túri","doi":"10.1016/j.ijms.2025.117565","DOIUrl":"10.1016/j.ijms.2025.117565","url":null,"abstract":"<div><div>Clumped isotope thermometry is a robust technique for reconstructing carbonate formation temperatures; however its analytical precision is highly dependent on instrumental stability. In this study, we address the challenge of achieving long-term Δ<sub>47</sub> repeatability using a Thermo Scientific™ 253 Plus 10 kV isotope ratio mass spectrometer (IRMS) coupled to a Kiel IV automated carbonate preparation device. The IRMS is equipped with 10<sup>13</sup> Ω resistors on high-gain Faraday cups. To minimize the impact of daily laboratory temperature fluctuations, we developed and implemented a prototype Peltier-based cooling system for the amplifier housing.</div><div>The combined approach reduced long-term Δ<sub>47</sub> standard deviation from 40 to 45 ppm (occasionally reaching up to 60 ppm under extreme conditions) to around 32 ppm. Validation was performed using international carbonate standards and natural travertine samples with known formation temperatures (10–95 °C), and results were bench-marked against previously published data. These improvements demonstrate a practical pathway towards achieving high-precision clumped isotope measurements under variable environmental conditions, and they provide a reproducible methodology for laboratories operating similar instrumentation in comparable settings.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"520 ","pages":"Article 117565"},"PeriodicalIF":1.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837276","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 : 2025-12-12DOI: 10.1016/j.ijms.2025.117564
Benny Neumark , Aviv Amirav
Explosives present significant challenges for chemical analysis. Traditional methods like High-Pressure Liquid Chromatography (HPLC) with UV/Vis detection often lack sufficient sensitivity and selectivity for complex matrices. HPLC coupled with Mass Spectrometry (MS) is also limited, as many explosives do not ionize efficiently with electrospray or atmospheric pressure chemical ionization. Gas Chromatography (GC) methods using Electron Capture Detection (ECD) or Mass Spectrometry (MS) with standard Electron Ionization (EI) also fall short. GC-MS with standard EI struggles due to thermal degradation at the injector and the hot metallic surface of the ion source and limited sensitivity. While GC-ECD can achieve lower detection limits, it lacks the selectivity of MS and poses safety risks due to its radioactive source.
GC-MS with Cold Electron Ionization (Cold EI) offers a superior solution. Cold EI incorporates a supersonic molecular beam (SMB) interface, allowing contact-free ionization of vibrationally cold molecules. This enhances molecular ions, improves sensitivity, reduces noise, and expands the range of compounds amenable for GC-MS analysis. The result is faster, more selective, and sensitive analysis that is ideal for the full range of organic explosives.
This study demonstrates the effectiveness of GC-MS with Cold EI for trace explosives analysis in soil. Using 17 explosive compounds listed in EPA Method 8095, we performed a complete method validation. The method's limits of detection were below 10 ng/g for all explosives, well below EPA thresholds for GC-ECD. GC-MS with Cold EI thus represents a significant advancement in mass spectrometry for forensic and environmental chemical analysis.
爆炸物对化学分析提出了重大挑战。传统的紫外/可见高压液相色谱（HPLC）检测方法对复杂的基质往往缺乏足够的灵敏度和选择性。高效液相色谱联用质谱（MS）也有局限性，因为许多炸药不能通过电喷雾或大气压化学电离有效地电离。使用电子捕获检测（ECD）的气相色谱（GC）方法或使用标准电子电离（EI）的质谱（MS）方法也存在不足。使用标准EI的GC-MS由于进样器的热降解和离子源的热金属表面以及有限的灵敏度而挣扎。GC-ECD虽然可以达到较低的检出限，但缺乏MS的选择性，并且由于其放射源存在安全风险。气相色谱-质谱与冷电子电离（冷EI）提供了一个优越的解决方案。Cold EI集成了一个超音速分子束（SMB）界面，允许振动冷分子的无接触电离。这增强了分子离子，提高了灵敏度，降低了噪声，并扩大了适用于GC-MS分析的化合物范围。结果是更快，更有选择性，更敏感的分析，是理想的全范围的有机炸药。本研究验证了冷EI气相色谱-质谱法分析土壤中痕量炸药的有效性。使用EPA方法8095中列出的17种爆炸性化合物进行了完整的方法验证。该方法对所有爆炸物的检测限均低于10 ng/g，远低于EPA对GC-ECD的阈值。GC-MS with Cold EI因此代表了质谱法在法医和环境化学分析方面的重大进步。
{"title":"Overcoming the limitations of explosives analysis by GC-MS with cold EI","authors":"Benny Neumark , Aviv Amirav","doi":"10.1016/j.ijms.2025.117564","DOIUrl":"10.1016/j.ijms.2025.117564","url":null,"abstract":"<div><div>Explosives present significant challenges for chemical analysis. Traditional methods like High-Pressure Liquid Chromatography (HPLC) with UV/Vis detection often lack sufficient sensitivity and selectivity for complex matrices. HPLC coupled with Mass Spectrometry (MS) is also limited, as many explosives do not ionize efficiently with electrospray or atmospheric pressure chemical ionization. Gas Chromatography (GC) methods using Electron Capture Detection (ECD) or Mass Spectrometry (MS) with standard Electron Ionization (EI) also fall short. GC-MS with standard EI struggles due to thermal degradation at the injector and the hot metallic surface of the ion source and limited sensitivity. While GC-ECD can achieve lower detection limits, it lacks the selectivity of MS and poses safety risks due to its radioactive source.</div><div>GC-MS with Cold Electron Ionization (Cold EI) offers a superior solution. Cold EI incorporates a supersonic molecular beam (SMB) interface, allowing contact-free ionization of vibrationally cold molecules. This enhances molecular ions, improves sensitivity, reduces noise, and expands the range of compounds amenable for GC-MS analysis. The result is faster, more selective, and sensitive analysis that is ideal for the full range of organic explosives.</div><div>This study demonstrates the effectiveness of GC-MS with Cold EI for trace explosives analysis in soil. Using 17 explosive compounds listed in EPA Method 8095, we performed a complete method validation. The method's limits of detection were below 10 ng/g for all explosives, well below EPA thresholds for GC-ECD. GC-MS with Cold EI thus represents a significant advancement in mass spectrometry for forensic and environmental chemical analysis.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"520 ","pages":"Article 117564"},"PeriodicalIF":1.7,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797438","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 : 2025-12-05DOI: 10.1016/j.ijms.2025.117555
Vitor M. Nilson , Nicole H. Lazzari , Suzan C. Zilli , Mariana R. Gama , Cristane S. Schwalm , Salatiel W. da Silva , Livia Streit , Tânia M. Pizzolato
Contaminants of environmental concern are compounds frequently detected in surface and groundwater due to anthropogenic activity. Among these compounds are atrazine (ATZ, a pesticide), carbamazepine (CBZ, an antiepileptic), and sulfamethoxazole (SMX, an antibiotic). These compounds are frequently detected in both raw and treated water samples, with concentrations ranging from ng L−1 to μg L−1. The degradation of these contaminants can lead to incomplete mineralization, potentially forming sub-products known as transformation products. Both parent compounds and by-products may be of toxicological concern. In the present study, samples resulting from the degradation of ATZ, CBZ, and SMX by combined UV-C irradiation and chlorination were analyzed to investigate the formation of transformation products and their associated toxicity. ATZ and SMX underwent nearly complete degradation (>99 %), whereas CBZ showed limited degradation (28 %). A total of 24 transformation products were identified using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) and a suspect screening approach. In silico quantitative structure–activity relationship analysis was performed to assess the potential risks of the compounds. Developmental toxicity, ready biodegradability, carcinogenicity, and mutagenicity were predicted using VEGA software. The results show that, while CBZ itself is not mutagenic, all transformation products except CBZ-255 are predicted as mutagenic with high reliability. CBZ transformation products are carcinogenic and toxicants with moderate to high reliability, and non-readily biodegradable with moderate to low reliability. All ATZ transformation products were found to be carcinogenic with moderate to low reliability, and toxicant with low reliability.
{"title":"Identification of transformation products by high resolution mass spectrometry wide scope screening, and risk assessment for atrazine, carbamazepine, and sulfamethoxazole aqueous solution, resulting from UV-C/chlorination","authors":"Vitor M. Nilson , Nicole H. Lazzari , Suzan C. Zilli , Mariana R. Gama , Cristane S. Schwalm , Salatiel W. da Silva , Livia Streit , Tânia M. Pizzolato","doi":"10.1016/j.ijms.2025.117555","DOIUrl":"10.1016/j.ijms.2025.117555","url":null,"abstract":"<div><div>Contaminants of environmental concern are compounds frequently detected in surface and groundwater due to anthropogenic activity. Among these compounds are atrazine (ATZ, a pesticide), carbamazepine (CBZ, an antiepileptic), and sulfamethoxazole (SMX, an antibiotic). These compounds are frequently detected in both raw and treated water samples, with concentrations ranging from ng L<sup>−1</sup> to μg L<sup>−1</sup>. The degradation of these contaminants can lead to incomplete mineralization, potentially forming sub-products known as transformation products. Both parent compounds and by-products may be of toxicological concern. In the present study, samples resulting from the degradation of ATZ, CBZ, and SMX by combined UV-C irradiation and chlorination were analyzed to investigate the formation of transformation products and their associated toxicity. ATZ and SMX underwent nearly complete degradation (>99 %), whereas CBZ showed limited degradation (28 %). A total of 24 transformation products were identified using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) and a suspect screening approach. <em>In silico</em> quantitative structure–activity relationship analysis was performed to assess the potential risks of the compounds. Developmental toxicity, ready biodegradability, carcinogenicity, and mutagenicity were predicted using VEGA software. The results show that, while CBZ itself is not mutagenic, all transformation products except CBZ-255 are predicted as mutagenic with high reliability. CBZ transformation products are carcinogenic and toxicants with moderate to high reliability, and non-readily biodegradable with moderate to low reliability. All ATZ transformation products were found to be carcinogenic with moderate to low reliability, and toxicant with low reliability.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"520 ","pages":"Article 117555"},"PeriodicalIF":1.7,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748584","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 : 2025-12-03DOI: 10.1016/j.ijms.2025.117553
Annabel S.J. Eardley-Brunt , Liwen Song , Oxford Acute Myocardial Infarction Study , Oxford Abdominal Aortic Aneurysm Study , Claire Vallance
Construction of large mass spectrometric data sets usually involves some combination of normalisation, scaling, and transformation of individual mass spectra in order to correct for technical (and sometimes biological) variation. Many different approaches to data normalisation have been reported, and there is no particular consensus on the best approach. The present study systematically evaluates a set of 24 normalisation, scaling, and transformation methods, and their 420 possible combinations, in the context of atmospheric solids analysis probe (ASAP) mass spectra of human blood plasma. The plasma samples came from two separate cohorts of patients, enrolled respectively in the Oxford Acute Myocardial Infarction (OxAMI) and Oxford Abdominal Aortic Aneurysm (OxAAA) clinical studies. Within each cohort, patients are classified according to a number of different clinical variables. We have investigated the effect of normalisation, scaling, and transformation method on subsequent clustering of the data into the classes of interest, and on machine-learning based classification of the data into the categories of interest. The choice of method was found to have a substantial effect on data clustering, measured via the clustering ratio , but a much smaller effect on machine-learning based classification, quantified via Cohen’s statistic. New intensity-histogram-based normalisation methods were found to have the greatest effect on clustering, while mean, median, vector, and AUC normalisation yielded the best machine-learning classification performance across multiple algorithms. High clustering ratios do not necessarily correlate with improved supervised classification outcomes, underscoring the need to consider subsequent data analysis methodology carefully when optimising data preprocessing pipelines.
{"title":"Optimising the choice of normalisation method for use in machine-learning classification of human blood plasma ambient ionisation mass spectra","authors":"Annabel S.J. Eardley-Brunt , Liwen Song , Oxford Acute Myocardial Infarction Study , Oxford Abdominal Aortic Aneurysm Study , Claire Vallance","doi":"10.1016/j.ijms.2025.117553","DOIUrl":"10.1016/j.ijms.2025.117553","url":null,"abstract":"<div><div>Construction of large mass spectrometric data sets usually involves some combination of normalisation, scaling, and transformation of individual mass spectra in order to correct for technical (and sometimes biological) variation. Many different approaches to data normalisation have been reported, and there is no particular consensus on the best approach. The present study systematically evaluates a set of 24 normalisation, scaling, and transformation methods, and their 420 possible combinations, in the context of atmospheric solids analysis probe (ASAP) mass spectra of human blood plasma. The plasma samples came from two separate cohorts of patients, enrolled respectively in the Oxford Acute Myocardial Infarction (OxAMI) and Oxford Abdominal Aortic Aneurysm (OxAAA) clinical studies. Within each cohort, patients are classified according to a number of different clinical variables. We have investigated the effect of normalisation, scaling, and transformation method on subsequent clustering of the data into the classes of interest, and on machine-learning based classification of the data into the categories of interest. The choice of method was found to have a substantial effect on data clustering, measured via the clustering ratio <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>R</mi></mrow></msub></math></span>, but a much smaller effect on machine-learning based classification, quantified via Cohen’s <span><math><mi>κ</mi></math></span> statistic. New intensity-histogram-based normalisation methods were found to have the greatest effect on clustering, while mean, median, vector, and AUC normalisation yielded the best machine-learning classification performance across multiple algorithms. High clustering ratios do not necessarily correlate with improved supervised classification outcomes, underscoring the need to consider subsequent data analysis methodology carefully when optimising data preprocessing pipelines.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"520 ","pages":"Article 117553"},"PeriodicalIF":1.7,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692375","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 : 2025-11-25DOI: 10.1016/j.ijms.2025.117554
Theis I. Solling , Nathan F. Dalleska , Syed S. Hussain , J.L. Beauchamp
Crude oil constitutes one of the most complex mixtures in the world and its characterization is challenging yet absolutely essential in any upstream related production context. Traditionally, this has been addressed in fractionation of the oil into saturates, aromatics, resins and asphaltenes; the SARA protocol. We have employed this conventional approach on three crude oils to compare results with mass spectrometric analysis in paper spray ionization mode where the crude does not enter inlets nor does it adhere to interfaces and therefore leaves no memory effects. Thus, it has proven to be an extremely convenient method for oil characterization as crude normally tends to damage analytical equipment by contamination. We have found that the densities of the three crude oils align very well with their SARA analyses in the sense that more saturates (alkanes) correspond to less dense oils. The paper spray ionization mass spectrometry handles the oil that consists of mostly saturates poorly and results in ill-defined peak shapes. A few peaks stand out and are most likely highly polar production compounds that are more easily ionized. On the other hand, the oils with aromatic components result in nice spectra and coupling the paper spray to HRMS clearly reveals the alkyl-aromatics. The combined results show that paper spray provides a fast valuable, non-contaminating route to oil characterization that provides actual structural insights; something that the traditional oil characterization methods can never be brought to do. We also show that production-relevant surfactants are readily characterized with paper spray. Thus, with some development it will facilitate the characterization of residual production chemicals in light crudes and guide the refining process.
{"title":"Paper spray analysis of crude oil samples: comparing traditional characterization schemes with mass spectrometric outcomes","authors":"Theis I. Solling , Nathan F. Dalleska , Syed S. Hussain , J.L. Beauchamp","doi":"10.1016/j.ijms.2025.117554","DOIUrl":"10.1016/j.ijms.2025.117554","url":null,"abstract":"<div><div>Crude oil constitutes one of the most complex mixtures in the world and its characterization is challenging yet absolutely essential in any upstream related production context. Traditionally, this has been addressed in fractionation of the oil into saturates, aromatics, resins and asphaltenes; the SARA protocol. We have employed this conventional approach on three crude oils to compare results with mass spectrometric analysis in paper spray ionization mode where the crude does not enter inlets nor does it adhere to interfaces and therefore leaves no memory effects. Thus, it has proven to be an extremely convenient method for oil characterization as crude normally tends to damage analytical equipment by contamination. We have found that the densities of the three crude oils align very well with their SARA analyses in the sense that more saturates (alkanes) correspond to less dense oils. The paper spray ionization mass spectrometry handles the oil that consists of mostly saturates poorly and results in ill-defined peak shapes. A few peaks stand out and are most likely highly polar production compounds that are more easily ionized. On the other hand, the oils with aromatic components result in nice spectra and coupling the paper spray to HRMS clearly reveals the alkyl-aromatics. The combined results show that paper spray provides a fast valuable, non-contaminating route to oil characterization that provides actual structural insights; something that the traditional oil characterization methods can never be brought to do. We also show that production-relevant surfactants are readily characterized with paper spray. Thus, with some development it will facilitate the characterization of residual production chemicals in light crudes and guide the refining process.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"520 ","pages":"Article 117554"},"PeriodicalIF":1.7,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145622999","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 : 2025-11-17DOI: 10.1016/j.ijms.2025.117552
Kavyasree Chintalapudi, Jonathan N. Chilaka, Abraham K. Badu-Tawiah
A reactive nano-electrospray ionization (nESI) platform is introduced that is capable of electro-catalytic reaction screening when fitted with non-inert Ir electrode. We hypothesized that the application of electrical potential to the Ir electrode in the presence of water (i.e., anodic discharge) will cause the generation of a transient active species MOx (•OH) at the electrode surface, which can dissociate further to provide a more reactive and hydrated oxide form MOx (OH)y. The electro-catalytic activity of the resultant nascent oxide was investigated by analyzing aldehydes in negative-ion mode mass spectrometry (MS) and detecting the corresponding carboxylic acids. Surface effect on oxidizing the C=O bond was confirmed by comparing with MS signal from non-electrical sonic spray and non-contact nESI experiments. Electronic effects were also investigated via the analysis of seven para-substituted benzaldehydes and results subjected to Hammett analysis, which confirmed electron donating groups to undergo anodic oxidation at a faster rate than electron withdrawing groups. These results have significance in analytical measurements and reaction screening via in-situ synthesized oxides.
{"title":"Reactive nano-electrospray ionization for in-situ oxidation of aldehydes for direct mass spectrometry analysis","authors":"Kavyasree Chintalapudi, Jonathan N. Chilaka, Abraham K. Badu-Tawiah","doi":"10.1016/j.ijms.2025.117552","DOIUrl":"10.1016/j.ijms.2025.117552","url":null,"abstract":"<div><div>A reactive nano-electrospray ionization (<strong>nESI</strong>) platform is introduced that is capable of electro-catalytic reaction screening when fitted with non-inert Ir electrode. We hypothesized that the application of electrical potential to the Ir electrode in the presence of water (i.e., anodic discharge) will cause the generation of a transient active species MO<sub>x</sub> (•OH) at the electrode surface, which can dissociate further to provide a more reactive and hydrated oxide form MO<sub>x</sub> (OH)<sub>y</sub>. The electro-catalytic activity of the resultant nascent oxide was investigated by analyzing aldehydes in negative-ion mode mass spectrometry (<strong>MS</strong>) and detecting the corresponding carboxylic acids. Surface effect on oxidizing the C=O bond was confirmed by comparing with MS signal from non-electrical sonic spray and non-contact nESI experiments. Electronic effects were also investigated via the analysis of seven para-substituted benzaldehydes and results subjected to Hammett analysis, which confirmed electron donating groups to undergo anodic oxidation at a faster rate than electron withdrawing groups. These results have significance in analytical measurements and reaction screening via in-situ synthesized oxides.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"519 ","pages":"Article 117552"},"PeriodicalIF":1.7,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614852","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 : 2025-11-11DOI: 10.1016/j.ijms.2025.117549
Luis Manuel Menéndez-Quintanal , Jose Manuel Matey , Marcelle D. Perretti , Nieves Rodríguez Paz
Cathinones represent one of the most prevalent classes of new psychoactive substances (NPS), largely due to the extensive variety of structural analogues. However, in forensic toxicology, their instability in post-mortem biological matrices such as blood and urine complicates their detection, making sample preservation at −20 °C essential prior to analysis. To overcome this limitation, dihydro (DH) metabolites—formed via reduction of the ketone group—have been proposed as reliable biomarkers of cathinone intake, owing to their enhanced stability. In this study, 28 DH-metabolites were synthesised through selective reduction of commercial cathinones. Their fragmentation behaviour was carefully studied using isotopically labelled analogues and analysed on different LC-HRMS platforms (Orbitrap and qTOF).
A predictive fragmentation model was developed, allowing for the identification of anticipated MS2 fragments and the characterization of specific diagnostic ions. These ions aid in the detection of DH-metabolites during untargeted LC-HRMS analyses. In line with previously described fragmentation pathways for synthetic cathinones, DH-metabolites can produce as well odd-electron ions from even-electron precursor ions during electrospray ionization (ESI). However, compared to their parent compounds, DH-metabolites exhibit some differences in fragmentation pathways.
Understanding the fragmentation mechanisms of a compound family is essential when applying non-targeted analysis methods using LC-HRMS techniques. The development of a predictive fragmentation model can significantly improve the detection of novel, unstable emerging cathinones in post-mortem samples or in wastewater monitoring, simply by targeting their DH-metabolites.
{"title":"Fragmentation pathways of dihydro-metabolites of synthetic cathinones by high-resolution mass spectrometry on Orbitrap and quadrupole time-of-flight (qTOF) mass spectrometers","authors":"Luis Manuel Menéndez-Quintanal , Jose Manuel Matey , Marcelle D. Perretti , Nieves Rodríguez Paz","doi":"10.1016/j.ijms.2025.117549","DOIUrl":"10.1016/j.ijms.2025.117549","url":null,"abstract":"<div><div>Cathinones represent one of the most prevalent classes of new psychoactive substances (NPS), largely due to the extensive variety of structural analogues. However, in forensic toxicology, their instability in post-mortem biological matrices such as blood and urine complicates their detection, making sample preservation at −20 °C essential prior to analysis. To overcome this limitation, dihydro (DH) metabolites—formed via reduction of the ketone group—have been proposed as reliable biomarkers of cathinone intake, owing to their enhanced stability. In this study, 28 DH-metabolites were synthesised through selective reduction of commercial cathinones. Their fragmentation behaviour was carefully studied using isotopically labelled analogues and analysed on different LC-HRMS platforms (Orbitrap and qTOF).</div><div>A predictive fragmentation model was developed, allowing for the identification of anticipated MS<sup>2</sup> fragments and the characterization of specific diagnostic ions. These ions aid in the detection of DH-metabolites during untargeted LC-HRMS analyses. In line with previously described fragmentation pathways for synthetic cathinones, DH-metabolites can produce as well odd-electron ions from even-electron precursor ions during electrospray ionization (ESI). However, compared to their parent compounds, DH-metabolites exhibit some differences in fragmentation pathways.</div><div>Understanding the fragmentation mechanisms of a compound family is essential when applying non-targeted analysis methods using LC-HRMS techniques. The development of a predictive fragmentation model can significantly improve the detection of novel, unstable emerging cathinones in post-mortem samples or in wastewater monitoring, simply by targeting their DH-metabolites.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"519 ","pages":"Article 117549"},"PeriodicalIF":1.7,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517063","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 : 2025-11-11DOI: 10.1016/j.ijms.2025.117551
Hadja Fatima Tbahriti , Ali Boukadoum , Esraa Mohamed Ahmed Mohamed Eljamil
Neurodegenerative disorders are highly prevalent diseases, representing a significant health care burden for millions of individuals worldwide, with scarce diagnostic and therapeutic capabilities. Conventional mass spectrometry methods for assessing biomarkers, although powerful, suffer from limited sensitivity, specificity and interpretability in complex biological matrices. This work introduces a new methodology that combines generative machine learning models and physics-based constraints for the discovery of biomarkers in neurodegenerative diseases. Next, we take advantage of the underlying mass spectrometry physics, including principles like mass conservation, isotope patterns and fragmentation rules, to impose on our generative models to generate biologically interpretable spectral representations. The framework shows better results compared with the traditional methods (AUC = 0.93 on multiple datasets across neurodegenerative diseases, sensitivity and specificity of 89.3 % and 92.1 %, respectively). Our approach, which integrates physics-informed constraints within a VAE-GAN framework, holds the potential to improve the precision of biomarker detection while providing interpretable insights into the biological mechanisms driving neurodegeneration. This present work introduces a revolutionary new paradigm for computational mass spectrometry, which acts as a bridge between data-driven discovery and mechanistic explanation, with exciting possibilities for early diagnosis and therapeutic target intervention in neurodegenerative disease.
{"title":"Generative mass spectrometry via physics-informed machine learning: A framework for biomarker discovery in neurodegenerative diseases","authors":"Hadja Fatima Tbahriti , Ali Boukadoum , Esraa Mohamed Ahmed Mohamed Eljamil","doi":"10.1016/j.ijms.2025.117551","DOIUrl":"10.1016/j.ijms.2025.117551","url":null,"abstract":"<div><div>Neurodegenerative disorders are highly prevalent diseases, representing a significant health care burden for millions of individuals worldwide, with scarce diagnostic and therapeutic capabilities. Conventional mass spectrometry methods for assessing biomarkers, although powerful, suffer from limited sensitivity, specificity and interpretability in complex biological matrices. This work introduces a new methodology that combines generative machine learning models and physics-based constraints for the discovery of biomarkers in neurodegenerative diseases. Next, we take advantage of the underlying mass spectrometry physics, including principles like mass conservation, isotope patterns and fragmentation rules, to impose on our generative models to generate biologically interpretable spectral representations. The framework shows better results compared with the traditional methods (AUC = 0.93 on multiple datasets across neurodegenerative diseases, sensitivity and specificity of 89.3 % and 92.1 %, respectively). Our approach, which integrates physics-informed constraints within a VAE-GAN framework, holds the potential to improve the precision of biomarker detection while providing interpretable insights into the biological mechanisms driving neurodegeneration. This present work introduces a revolutionary new paradigm for computational mass spectrometry, which acts as a bridge between data-driven discovery and mechanistic explanation, with exciting possibilities for early diagnosis and therapeutic target intervention in neurodegenerative disease.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"519 ","pages":"Article 117551"},"PeriodicalIF":1.7,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517065","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}
The negative and positive ions formed on the surface of the heated Re, W, and Mo under ambient atmosphere were measured by mass spectrometry. Heated metal surfaces are quickly oxidized under ambient atmospheric pressure with the presence of oxygen and moisture in the air. Metal oxides of Re2O7, WO3, and MoO3 formed on the heated Re, W, and Mo surfaces reacted with water (moisture in the air) to form ReO4−, WO3−OH, and MoO3−OH, respectively. The formation of WO3−OH and MoO3−OH were followed by successive dehydration condensation reactions to form (WO3)n−OH (n = 0–14) and (MoO3)n−OH (n = 0–41), i.e., (WO3)n−1−OH + HOWO2OH → (WO3)n−OH + H2O and (MoO3)n−1−OH + HOMoO3OH → (MoO3)n−OH + H2O, respectively. The magic number of n = 6 was observed for (WO3)n−OH and (MoO3)n−OH, likely due to the formation of a cyclic intramolecular hydrogen bond between the terminal O− and OH in O−(WO3)5WO2OH. No dehydrated condensed ions were detected for Re because the primary ion ReO4− does not have a hydroxyl group for the occurrence of dehydration reactions. Evidence for the desorption of metal oxides of Re2O7, WO3, and MoO3 as neutral forms was not obtained. This suggests that these neutral products react almost instantly with water to form metallic acids on the surface followed by the formation of polyoxometalate anions.
{"title":"Thermal desorption of preformed polyoxometalate anions on the heated oxidized Re, W, and Mo under ambient atmospheric pressure studied by mass spectrometry","authors":"Kenzo Hiraoka , Stephanie Rankin-Turner , Dilshadbek T. Usmanov , Satoshi Ninomiya","doi":"10.1016/j.ijms.2025.117550","DOIUrl":"10.1016/j.ijms.2025.117550","url":null,"abstract":"<div><div>The negative and positive ions formed on the surface of the heated Re, W, and Mo under ambient atmosphere were measured by mass spectrometry. Heated metal surfaces are quickly oxidized under ambient atmospheric pressure with the presence of oxygen and moisture in the air. Metal oxides of Re<sub>2</sub>O<sub>7</sub>, WO<sub>3</sub>, and MoO<sub>3</sub> formed on the heated Re, W, and Mo surfaces reacted with water (moisture in the air) to form ReO<sub>4</sub><sup>−</sup>, WO<sub>3</sub><sup>−</sup>OH, and MoO<sub>3</sub><sup>−</sup>OH, respectively. The formation of WO<sub>3</sub><sup>−</sup>OH and MoO<sub>3</sub><sup>−</sup>OH were followed by successive dehydration condensation reactions to form (WO<sub>3</sub>)<sub>n</sub><sup>−</sup>OH (n = 0–14) and (MoO<sub>3</sub>)<sub>n</sub><sup>−</sup>OH (n = 0–41), i.e., (WO<sub>3</sub>)<sub>n−1</sub><sup>−</sup>OH + HOWO<sub>2</sub>OH → (WO<sub>3</sub>)<sub>n</sub><sup>−</sup>OH + H<sub>2</sub>O and (MoO<sub>3</sub>)<sub>n−1</sub><sup>−</sup>OH + HOMoO<sub>3</sub>OH → (MoO<sub>3</sub>)<sub>n</sub><sup>−</sup>OH + H<sub>2</sub>O, respectively. The magic number of n = 6 was observed for (WO<sub>3</sub>)<sub>n</sub><sup>−</sup>OH and (MoO<sub>3</sub>)<sub>n</sub><sup>−</sup>OH, likely due to the formation of a cyclic intramolecular hydrogen bond between the terminal O<sup>−</sup> and OH in O<sup>−</sup>(WO<sub>3</sub>)<sub>5</sub>WO<sub>2</sub>OH. No dehydrated condensed ions were detected for Re because the primary ion ReO<sub>4</sub><sup>−</sup> does not have a hydroxyl group for the occurrence of dehydration reactions. Evidence for the desorption of metal oxides of Re<sub>2</sub>O<sub>7</sub>, WO<sub>3</sub>, and MoO<sub>3</sub> as neutral forms was not obtained. This suggests that these neutral products react almost instantly with water to form metallic acids on the surface followed by the formation of polyoxometalate anions.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"519 ","pages":"Article 117550"},"PeriodicalIF":1.7,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517062","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 : 2025-11-05DOI: 10.1016/j.ijms.2025.117548
Matjaž Finšgar, Katja Andrina Varda
This study focuses on the surface and subsurface characterization of a pharmaceutical tablet containing sodium metamizolate (NaMET), with an emphasis on mass spectrometry using time-of-flight secondary ion mass spectrometry (ToF-SIMS). ToF-SIMS enabled the identification of NaMET-specific fragment ions, which served as signals for the determination of the spatial distribution of this active pharmaceutical ingredient (API) within the tablet matrix. A ToF-SIMS fragmentation mechanism for NaMET was proposed based on the ToF-SIMS spectra analysis measured on a NaMET reference standard. 3D ToF-SIMS imaging showed heterogeneous localization of the API across a 5 μm depth. Complementary techniques, including 3D profilometry and atomic force microscopy (AFM), provided surface roughness and morphological data, while X-ray photoelectron spectroscopy (XPS) confirmed the elemental composition and chemical states. Depth profiling by XPS further supported the non-uniform distribution of NaMET.
{"title":"Surface analysis of sodium metamizolate as an active pharmaceutical ingredient in solid form","authors":"Matjaž Finšgar, Katja Andrina Varda","doi":"10.1016/j.ijms.2025.117548","DOIUrl":"10.1016/j.ijms.2025.117548","url":null,"abstract":"<div><div>This study focuses on the surface and subsurface characterization of a pharmaceutical tablet containing sodium metamizolate (NaMET), with an emphasis on mass spectrometry using time-of-flight secondary ion mass spectrometry (ToF-SIMS). ToF-SIMS enabled the identification of NaMET-specific fragment ions, which served as signals for the determination of the spatial distribution of this active pharmaceutical ingredient (API) within the tablet matrix. A ToF-SIMS fragmentation mechanism for NaMET was proposed based on the ToF-SIMS spectra analysis measured on a NaMET reference standard. 3D ToF-SIMS imaging showed heterogeneous localization of the API across a 5 μm depth. Complementary techniques, including 3D profilometry and atomic force microscopy (AFM), provided surface roughness and morphological data, while X-ray photoelectron spectroscopy (XPS) confirmed the elemental composition and chemical states. Depth profiling by XPS further supported the non-uniform distribution of NaMET.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"519 ","pages":"Article 117548"},"PeriodicalIF":1.7,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463157","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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