Pub Date : 2025-04-17DOI: 10.1016/j.ijms.2025.117455
Carter Lantz , Muhammad A. Zenaidee , Denise Tran , Karl Biggs , Gal Bitan , Rachel R. Ogorzalek Loo , Joseph A. Loo
Phosphorylation is a ubiquitous protein modification that is known to play important roles in many biological phenomena including cell signaling, the opening and closing of membrane protein channels, and even triggering of amyloid protein aggregation. Despite the effects phosphorylation has on protein function, the impact phosphorylation has on the structure of proteins is not well understood. To determine how phosphorylation affects the structure of proteins, top-down mass spectrometry (TD-MS) and ion mobility-mass spectrometry (IM-MS) were performed on various phosphorylated proteins and their dephosphorylated proteoforms. TD-MS with collision- and electron-based fragmentation techniques was utilized to locate phosphorylation sites on the intrinsically disordered amyloid proteins β-casein and α-synuclein. TD-MS also provided evidence that alkaline phosphatase dephosphorylates β-casein from the N-terminus to the C-terminus. Furthermore, IM-MS of common phosphorylated proteins such as β-casein, α-casein, ovalbumin, and phosvitin indicates that phosphorylation promotes compaction of protein structure in denaturing as well as native conditions. Increases in abundance of more compact conformers are also observed when the disease related amyloid protein α-synuclein is phosphorylated at serine 129. We interpret the increased abundance of more compact conformers when proteins are phosphorylated as evidence that salt bridges form between negatively charged phosphates and positively charged residues, which alters protein structure. Salt bridge formation due to phosphorylation could be a mechanism for regulating protein function and be responsible for many of the phenomena observed in nature.
{"title":"Mass spectrometry structural analysis of intrinsically disordered phosphoproteins","authors":"Carter Lantz , Muhammad A. Zenaidee , Denise Tran , Karl Biggs , Gal Bitan , Rachel R. Ogorzalek Loo , Joseph A. Loo","doi":"10.1016/j.ijms.2025.117455","DOIUrl":"10.1016/j.ijms.2025.117455","url":null,"abstract":"<div><div>Phosphorylation is a ubiquitous protein modification that is known to play important roles in many biological phenomena including cell signaling, the opening and closing of membrane protein channels, and even triggering of amyloid protein aggregation. Despite the effects phosphorylation has on protein function, the impact phosphorylation has on the structure of proteins is not well understood. To determine how phosphorylation affects the structure of proteins, top-down mass spectrometry (TD-MS) and ion mobility-mass spectrometry (IM-MS) were performed on various phosphorylated proteins and their dephosphorylated proteoforms. TD-MS with collision- and electron-based fragmentation techniques was utilized to locate phosphorylation sites on the intrinsically disordered amyloid proteins β-casein and α-synuclein. TD-MS also provided evidence that alkaline phosphatase dephosphorylates β-casein from the N-terminus to the C-terminus. Furthermore, IM-MS of common phosphorylated proteins such as β-casein, α-casein, ovalbumin, and phosvitin indicates that phosphorylation promotes compaction of protein structure in denaturing as well as native conditions. Increases in abundance of more compact conformers are also observed when the disease related amyloid protein α-synuclein is phosphorylated at serine 129. We interpret the increased abundance of more compact conformers when proteins are phosphorylated as evidence that salt bridges form between negatively charged phosphates and positively charged residues, which alters protein structure. Salt bridge formation due to phosphorylation could be a mechanism for regulating protein function and be responsible for many of the phenomena observed in nature.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117455"},"PeriodicalIF":1.6,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845025","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 : 2025-04-14DOI: 10.1016/j.ijms.2025.117457
A. Emin Atik , Sila Karaca , Talat Yalcin
Peptide fragmentation chemistry is essential for the sequence elucidation of proteins through tandem mass spectrometry (MS/MS). In this study, we examine the gas-phase fragmentation of b3 ions from model tripeptides under low-energy CID conditions, focusing on the pathway leading to the stable formation of a3 ions from b3 ions. The study utilized C-terminal amidated model tripeptides, including YGG-NH2, GYG-NH2, and GGX-NH2, where X represents D, E, H, Q, C, S, F, and Y. Our results reveal that only tripeptides with phenylalanine (F) and tyrosine (Y) as the third residue yield a3 ions upon b3 ion fragmentation under the applied experimental conditions, suggesting a unique stabilizing role of aromatic side chains in facilitating this pathway. Our theoretical studies indicate that the a3 ions from GGF-NH2 and GGY-NH2 preferentially adopt an energetically favored linear imine-protonated isomer, which is lower in energy by 3.29 kcal/mol and 4.17 kcal/mol, respectively, compared to their 7-membered ring isomers protonated at the ring imine. The latter structure has been previously assigned for the GGG sequence as a predominant structure, supported by IR spectroscopy and DFT calculations (JACS, 2010, 132, 14,766–14779). We proposed a plausible fragmentation mechanism for the a3 ions based on the linear imine-protonated structure. These findings provide insights into residue-specific fragmentation mechanisms and enhance our understanding of peptide ion dissociation, particularly in small peptides.
{"title":"Residue-specific pathways in peptide fragmentation: The role of aromatic side chain in a3 ion formation from b3 ion","authors":"A. Emin Atik , Sila Karaca , Talat Yalcin","doi":"10.1016/j.ijms.2025.117457","DOIUrl":"10.1016/j.ijms.2025.117457","url":null,"abstract":"<div><div>Peptide fragmentation chemistry is essential for the sequence elucidation of proteins through tandem mass spectrometry (MS/MS). In this study, we examine the gas-phase fragmentation of <em>b</em><sub>3</sub> ions from model tripeptides under low-energy CID conditions, focusing on the pathway leading to the stable formation of <em>a</em><sub>3</sub> ions from <em>b</em><sub>3</sub> ions. The study utilized C-terminal amidated model tripeptides, including YGG-NH<sub>2</sub>, GYG-NH<sub>2</sub>, and GGX-NH<sub>2</sub>, where X represents D, E, H, Q, C, S, F, and Y. Our results reveal that only tripeptides with phenylalanine (F) and tyrosine (Y) as the third residue yield <em>a</em><sub>3</sub> ions upon <em>b</em><sub>3</sub> ion fragmentation under the applied experimental conditions, suggesting a unique stabilizing role of aromatic side chains in facilitating this pathway. Our theoretical studies indicate that the <em>a</em><sub>3</sub> ions from GGF-NH<sub>2</sub> and GGY-NH<sub>2</sub> preferentially adopt an energetically favored linear imine-protonated isomer, which is lower in energy by 3.29 kcal/mol and 4.17 kcal/mol, respectively, compared to their 7-membered ring isomers protonated at the ring imine. The latter structure has been previously assigned for the GGG sequence as a predominant structure, supported by IR spectroscopy and DFT calculations <em>(JACS, 2010, 132, 14,766–14779)</em>. We proposed a plausible fragmentation mechanism for the <em>a</em><sub>3</sub> ions based on the linear imine-protonated structure. These findings provide insights into residue-specific fragmentation mechanisms and enhance our understanding of peptide ion dissociation, particularly in small peptides.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117457"},"PeriodicalIF":1.6,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828450","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 : 2025-04-14DOI: 10.1016/j.ijms.2025.117456
Zhe Fang , Haizhou Wang , Lei Wang , Kai Li
The determination of iron using ICP-MS-MS is complicated due to the polyatomic spectral interferences, notably the 40Ar16O+ on the abundant 56Fe isotope. In this research, the utilization of three gases—helium, hydrogen, and methane—to accurately quantify iron was proposed using the on-mass mode by inductively coupled plasma tandem mass spectrometer. The conditions of the collision/reaction cell were optimized, particularly the gas flow rate and the hexapole bias voltage, for iron analysis. Different mechanisms, including collision and reactions like charge transfer reactions, hydrogen atom transfer reactions, and proton transfer reactions, were explored. In terms of sensitivity and background equivalent concentration (BEC), the hydrogen mode exhibited the highest sensitivity and the lowest BEC. The methane mode yields a comparable BEC to that of the hydrogen mode with a threefold reduction in sensitivity. The limit of quantification (LOQ) under the hydrogen reaction mode was as low as 0.028 μg/g.The analysis results of the national standard substance GBW07159 were in excellent agreement with the certified values, and the relative standard deviation (RSD) for n = 11 was less than 5 % in the three modes. The measured values and spiked recoveries for rare earth oxides were essentially consistent between the hydrogen and methane modes. Following validation, the hydrogen and methane reaction modes have been shown to accurately analyze iron in rare earth and rare earth oxides with high accuracy and stability, surpassing the helium mode in terms of collision mechanism.
{"title":"Approaches with different reaction gases for the determination of iron in rare earth samples based on on-mass mode by inductively coupled plasma tandem mass spectrometer","authors":"Zhe Fang , Haizhou Wang , Lei Wang , Kai Li","doi":"10.1016/j.ijms.2025.117456","DOIUrl":"10.1016/j.ijms.2025.117456","url":null,"abstract":"<div><div>The determination of iron using ICP-MS-MS is complicated due to the polyatomic spectral interferences, notably the <sup>40</sup>Ar<sup>16</sup>O<sup>+</sup> on the abundant <sup>56</sup>Fe isotope. In this research, the utilization of three gases—helium, hydrogen, and methane—to accurately quantify iron was proposed using the on-mass mode by inductively coupled plasma tandem mass spectrometer. The conditions of the collision/reaction cell were optimized, particularly the gas flow rate and the hexapole bias voltage, for iron analysis. Different mechanisms, including collision and reactions like charge transfer reactions, hydrogen atom transfer reactions, and proton transfer reactions, were explored. In terms of sensitivity and background equivalent concentration (BEC), the hydrogen mode exhibited the highest sensitivity and the lowest BEC. The methane mode yields a comparable BEC to that of the hydrogen mode with a threefold reduction in sensitivity. The limit of quantification (LOQ) under the hydrogen reaction mode was as low as 0.028 μg/g.The analysis results of the national standard substance GBW07159 were in excellent agreement with the certified values, and the relative standard deviation (RSD) for n = 11 was less than 5 % in the three modes. The measured values and spiked recoveries for rare earth oxides were essentially consistent between the hydrogen and methane modes. Following validation, the hydrogen and methane reaction modes have been shown to accurately analyze iron in rare earth and rare earth oxides with high accuracy and stability, surpassing the helium mode in terms of collision mechanism.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117456"},"PeriodicalIF":1.6,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839724","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 : 2025-04-13DOI: 10.1016/j.ijms.2025.117446
Zhiyuan Luo , Shiyu Cheng , Zhiyang Wei , Lixin Shan , Zhangqi Yu , Teng Yang , Yongze Gao , Jinian Shu
The occasional mix of the poisonous adulterant Illicium lanceolatum fruits in the Illicium verum fruits (Chinese star anise) sold in the agricultural market causes a food safety concern. Therefore, rapid differentiation between the fruits of these two species is essential for food safety. This paper reports a mass spectrometric recognition method between the Illicium verum and Illicium lanceolatum fruits. A high-sensitivity VUV photoionization time-of-flight mass spectrometer (PI-MS) directly sampled the volatile organics emitted from these two fruits via dynamic headspace. The assay results show that the mass peak of trans-anethole (m/z = 148) is predominant in the mass spectrum of Illicium verum, whereas no significant peak is observed at m/z 148 in the mass spectrum of Illicium lanceolatum. In contrast, the mass peak at m/z 154 with moderate intensity, associated with oxygenated monoterpenes, is detected in Illicium lanceolatum but not detected in Illicium verum. A developed chemical pattern recognition method achieved recognition with 100 % confidence between the Illicium verum and Illicium lanceolatum fruits. This study provides a new identification method using PI-MS to rapidly differentiate the Illicium verum and poisonous adulterant Illicium lanceolatum fruits. The advantages of soft ionization in PI-MS, coupled with its capability to detect volatile gases and the avoidance of complex sample pre-treatment steps, facilitate rapid and easily interpretable mass spectral detection.
{"title":"Rapid and accurate identification of Illicium verum and its poisonous adulterant Illicium lanceolatum based on high-sensitivity VUV photoionization mass spectrometry","authors":"Zhiyuan Luo , Shiyu Cheng , Zhiyang Wei , Lixin Shan , Zhangqi Yu , Teng Yang , Yongze Gao , Jinian Shu","doi":"10.1016/j.ijms.2025.117446","DOIUrl":"10.1016/j.ijms.2025.117446","url":null,"abstract":"<div><div>The occasional mix of the poisonous adulterant <em>Illicium lanceolatum</em> fruits in the <em>Illicium verum</em> fruits (Chinese star anise) sold in the agricultural market causes a food safety concern. Therefore, rapid differentiation between the fruits of these two species is essential for food safety. This paper reports a mass spectrometric recognition method between the <em>Illicium verum</em> and <em>Illicium lanceolatum</em> fruits. A high-sensitivity VUV photoionization time-of-flight mass spectrometer (PI-MS) directly sampled the volatile organics emitted from these two fruits via dynamic headspace. The assay results show that the mass peak of trans-anethole (<em>m/z</em> = 148) is predominant in the mass spectrum of <em>Illicium verum</em>, whereas no significant peak is observed at <em>m/z</em> 148 in the mass spectrum of <em>Illicium lanceolatum</em>. In contrast, the mass peak at <em>m/z</em> 154 with moderate intensity, associated with oxygenated monoterpenes, is detected in <em>Illicium lanceolatum</em> but not detected in <em>Illicium verum</em>. A developed chemical pattern recognition method achieved recognition with 100 % confidence between the <em>Illicium verum</em> and <em>Illicium lanceolatum</em> fruits. This study provides a new identification method using PI-MS to rapidly differentiate the <em>Illicium verum</em> and poisonous adulterant <em>Illicium lanceolatum</em> fruits. The advantages of soft ionization in PI-MS, coupled with its capability to detect volatile gases and the avoidance of complex sample pre-treatment steps, facilitate rapid and easily interpretable mass spectral detection.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117446"},"PeriodicalIF":1.6,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825939","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 : 2025-04-12DOI: 10.1016/j.ijms.2025.117445
Henry Cardwell , Paul Acoria , Alexis Brender A Brandis , Kathy Huynh , Madeleine Lamb , Sophie Messinger , Daria Moody , Laurel Nicks , Hao Qian , Shantanu Rastogi , Trinh Ton , Anna Grace Towler , Mark Valasquez , Jennifer Poutsma , John C. Poutsma
The gas-phase proton affinities (PA) for a series of proline-containing dipeptides have been measured in an ESI triple quadrupole instrument using the extended kinetic method (EKM). Proton affinities of ProCys (1), ProMet (2), ProSer (3), ProThr (4), ProTyr (5), ProPhe (6), and ProTrp (7) were determined to be 966.9 ± 5.3, 987.9 ± 10.4, 978.4 ± 6.1, 978.3 ± 6.1, 993.9 ± 11.2, 985.1 ± 10.7, and 998.7 ± 7.6 kJ/mol, respectively. Predictions for the proton affinities for 1–7 were also obtained through isodesmic calculations at the B3LYP/6–311++G(d,p)//B3LYP/6-31+G(d) level of theory. As with a previous study on the proton affinities of ProXxx dipeptides with aliphatic side chains (Cardwell et al., Int. J. Mass Spectrom.2025, 507, 117352) the agreement between theory and experiment is mixed. For the two dipeptides with sulfur in the side chain we find excellent agreement between the EKM and calculated proton affinities. For the three dipeptides with hydroxyl groups in the side chain, the experimental values are between 7.2 and 13.2 kJ/mol larger than the computed proton affinities. Additional single point energy calculations on 3–5 with B3LYP/6–311++G(2df,2p) basis sets give predicted proton affinities that are somewhat smaller than those predicted with the B3LYP/6–311++G9d,p) basis set. MP2/6-311z++G(2df,2p) single point energy calculations on 3 and 4 give calculated proton affinities within 1 kJ/mol of the B3LYP/6–311++G(d,p) values. It appears that the EKM values for 3–5 are systematically too high, possible o to the extrapolation required to obtain the isothermal point in the EKM workup due to the large protonation entropies of the dipeptides. This result is also seen to a lesser extent for ProPhe and ProTrp in which the EKM proton affinities are 5–6 kJ/mol larger than the calculated values. As with the aliphatic ProXxx dipeptides from our previous study, we recommend using the calculated proton affinities for 1–7 with the experimental proton affinities as upper limits.
{"title":"Gas phase proton affinities of proline-containing peptides. 2: ProCys, ProMet, ProSer, ProThr, ProTyr, ProPhe, and ProTrp","authors":"Henry Cardwell , Paul Acoria , Alexis Brender A Brandis , Kathy Huynh , Madeleine Lamb , Sophie Messinger , Daria Moody , Laurel Nicks , Hao Qian , Shantanu Rastogi , Trinh Ton , Anna Grace Towler , Mark Valasquez , Jennifer Poutsma , John C. Poutsma","doi":"10.1016/j.ijms.2025.117445","DOIUrl":"10.1016/j.ijms.2025.117445","url":null,"abstract":"<div><div>The gas-phase proton affinities (PA) for a series of proline-containing dipeptides have been measured in an ESI triple quadrupole instrument using the extended kinetic method (EKM). Proton affinities of ProCys (<strong>1</strong>), ProMet (<strong>2</strong>), ProSer (<strong>3</strong>), ProThr (<strong>4</strong>), ProTyr (<strong>5</strong>), ProPhe (<strong>6</strong>), and ProTrp (<strong>7</strong>) were determined to be 966.9 ± 5.3, 987.9 ± 10.4, 978.4 ± 6.1, 978.3 ± 6.1, 993.9 ± 11.2, 985.1 ± 10.7, and 998.7 ± 7.6 kJ/mol, respectively. Predictions for the proton affinities for <strong>1</strong>–<strong>7</strong> were also obtained through isodesmic calculations at the B3LYP/6–311++G(d,p)//B3LYP/6-31+G(d) level of theory. As with a previous study on the proton affinities of ProXxx dipeptides with aliphatic side chains (Cardwell et al., <em>Int. J. Mass Spectrom.</em> <strong>2025</strong>, <em>507</em>, 117352) the agreement between theory and experiment is mixed. For the two dipeptides with sulfur in the side chain we find excellent agreement between the EKM and calculated proton affinities. For the three dipeptides with hydroxyl groups in the side chain, the experimental values are between 7.2 and 13.2 kJ/mol larger than the computed proton affinities. Additional single point energy calculations on <strong>3</strong>–<strong>5</strong> with B3LYP/6–311++G(2df,2p) basis sets give predicted proton affinities that are somewhat smaller than those predicted with the B3LYP/6–311++G9d,p) basis set. MP2/6-311z++G(2df,2p) single point energy calculations on <strong>3 and 4</strong> give calculated proton affinities within 1 kJ/mol of the B3LYP/6–311++G(d,p) values. It appears that the EKM values for <strong>3</strong>–<strong>5</strong> are systematically too high, possible o to the extrapolation required to obtain the isothermal point in the EKM workup due to the large protonation entropies of the dipeptides. This result is also seen to a lesser extent for ProPhe and ProTrp in which the EKM proton affinities are 5–6 kJ/mol larger than the calculated values. As with the aliphatic ProXxx dipeptides from our previous study, we recommend using the calculated proton affinities for <strong>1</strong>–<strong>7</strong> with the experimental proton affinities as upper limits.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117445"},"PeriodicalIF":1.6,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852037","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 : 2025-04-01DOI: 10.1016/j.ijms.2025.117444
Sudam S. Mane, Easton K. Cox, Cole D. Warner, David V. Dearden, Kenneth W. Lee
Current tandem mass spectrometry-based methods for cyclodextrin characterization rely on exact mass and fragmentation patterns. Orthogonal methods are designed to provide additional information, increasing confidence in characterization. Ion mobility spectrometry (IMS) and mass spectrometry (MS) provide two dimensions where MS separates based on mass-to-charge and IMS separates based on size, shape, and charge. Here, we report new gas phase behavior of sodiated cyclodextrins revealed by cyclic IMS coupled to tandem MS. Gas phase ion activation prior to IMS separation on sodiated α-, β-, and γ-cyclodextrins generates isomeric species with different mobilities. Following gas phase mobility separation, fragmentation studies on the activation-generated isomers showed a greater degree of fragmentation than was observed for the original sodiated cyclodextrins. These findings suggest that sodiated cyclodextrins undergo structural changes upon activation, with the newly formed isomers significantly contributing to the observed fragmentation. To our knowledge this is the first report on separation of isomeric ions generated upon collisional activation of sodiated cyclodextrins in the gas phase. The results of this study can be used for better understanding of cyclodextrin fragmentation, suggesting that fragmentation occurs after an initial isomerization, possibly to a ring-opened form. Additionally, these findings can be used to develop more specific methodologies for cyclodextrin characterization.
{"title":"Cyclic IMS-MS evidence for potential ring opening in collisionally activated sodiated cyclodextrins","authors":"Sudam S. Mane, Easton K. Cox, Cole D. Warner, David V. Dearden, Kenneth W. Lee","doi":"10.1016/j.ijms.2025.117444","DOIUrl":"10.1016/j.ijms.2025.117444","url":null,"abstract":"<div><div>Current tandem mass spectrometry-based methods for cyclodextrin characterization rely on exact mass and fragmentation patterns. Orthogonal methods are designed to provide additional information, increasing confidence in characterization. Ion mobility spectrometry (IMS) and mass spectrometry (MS) provide two dimensions where MS separates based on mass-to-charge and IMS separates based on size, shape, and charge. Here, we report new gas phase behavior of sodiated cyclodextrins revealed by cyclic IMS coupled to tandem MS. Gas phase ion activation prior to IMS separation on sodiated α-, β-, and γ-cyclodextrins generates isomeric species with different mobilities. Following gas phase mobility separation, fragmentation studies on the activation-generated isomers showed a greater degree of fragmentation than was observed for the original sodiated cyclodextrins. These findings suggest that sodiated cyclodextrins undergo structural changes upon activation, with the newly formed isomers significantly contributing to the observed fragmentation. To our knowledge this is the first report on separation of isomeric ions generated upon collisional activation of sodiated cyclodextrins in the gas phase. The results of this study can be used for better understanding of cyclodextrin fragmentation, suggesting that fragmentation occurs after an initial isomerization, possibly to a ring-opened form. Additionally, these findings can be used to develop more specific methodologies for cyclodextrin characterization.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117444"},"PeriodicalIF":1.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863381","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}
Effectively amide bond construction between substances located in two immiscible liquids is a key point in the covalent-combination of the two parts with totally different characters. Herein, we demonstrated that aminolysis reactions between substances located in two immiscible solutions can be promoted in microdroplets without phase transfer catalyst, leading to amide bond formation products. Furthermore, in the biphasic reaction of microdroplets, size of the hydrophobic group and length of the alkyl chain in an activated ester may also affect a lot on the aminolysis reaction. This result will provide us a further insight on interfacial microdroplet reaction between substances located in two immiscible liquid phases and a new approach for ligation of two substances with totally different properties.
{"title":"Amide bond formation between substances located in two immiscible liquid phases without phase-transfer catalyst","authors":"Xiao-Fei Gao , Wei Xiao , Meng Qiu , Zhi-Gang Cheng , Xiang-Zhao Chen","doi":"10.1016/j.ijms.2025.117443","DOIUrl":"10.1016/j.ijms.2025.117443","url":null,"abstract":"<div><div>Effectively amide bond construction between substances located in two immiscible liquids is a key point in the covalent-combination of the two parts with totally different characters. Herein, we demonstrated that aminolysis reactions between substances located in two immiscible solutions can be promoted in microdroplets without phase transfer catalyst, leading to amide bond formation products. Furthermore, in the biphasic reaction of microdroplets, size of the hydrophobic group and length of the alkyl chain in an activated ester may also affect a lot on the aminolysis reaction. This result will provide us a further insight on interfacial microdroplet reaction between substances located in two immiscible liquid phases and a new approach for ligation of two substances with totally different properties.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"512 ","pages":"Article 117443"},"PeriodicalIF":1.6,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776880","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 : 2025-03-26DOI: 10.1016/j.ijms.2025.117442
Amir Fayyaz , Muhammad Aslam Baig , Rizwan Ahmed , Muhammad Waqas
In this study, we present the isotope analysis of zinc plasma using laser ablation time-of-flight mass spectrometry (LA-TOF-MS). The isotopes were detected based on their mass-to-charge (m/z) ratio. To improve the resolution of LA-TOF-MS, an aluminum disk with a 1 mm central opening was placed within a cylindrical magnetic filter (∼1 T) along the ion signal path. The electric field was applied using DC power, and the signal-to-noise ratio was monitored via an oscilloscope. Zinc isotopes; Zn-64, Zn-66, and Zn-68 were observed with high resolution within 1 μs by systematically applying electric fields in the ionization and extraction regions. The full-width half maximum (FWHM) significantly decreased with increasing electric field strength, from 0.215 to 0.137 μs for Zn-64, 0.294 to 0.146 μs for Zn-66, and 0.239 to 0.190 μs for Zn-68. The mass concentrations for Zn-64, Zn-66, and Zn-68 were estimated to be 48.6 %, 27.9 %, and 18.8 %, respectively, within ±0.1 % uncertainty, which is in agreement with the reported values in the literature. Laser-induced breakdown spectroscopy (LIBS) is used for plasma characterization and rapid qualitative identification of the constituent elements in the sample under study. Energy-dispersive X-ray (EDX) spectroscopy is applied for the cross-validation of the qualitative results obtained using LIBS. Since spectroscopically pure zinc was used in this study, spectral lines of any impurity elements may also appear in both spectra. However, LA-TOF-MS yields peaks along the arrival time scale of the constituent ions in the sample. The results demonstrate that LA-TOF-MS, combined with LIBS and EDX techniques, suggest a rapid method for elemental/isotope analysis.
{"title":"Isotopic analysis of zinc plasma using Laser‒Ablation Time‒of‒Flight mass spectrometer","authors":"Amir Fayyaz , Muhammad Aslam Baig , Rizwan Ahmed , Muhammad Waqas","doi":"10.1016/j.ijms.2025.117442","DOIUrl":"10.1016/j.ijms.2025.117442","url":null,"abstract":"<div><div>In this study, we present the isotope analysis of zinc plasma using laser ablation time-of-flight mass spectrometry (LA-TOF-MS). The isotopes were detected based on their mass-to-charge (<em>m</em>/<em>z</em>) ratio. To improve the resolution of LA-TOF-MS, an aluminum disk with a 1 mm central opening was placed within a cylindrical magnetic filter (∼1 T) along the ion signal path. The electric field was applied using DC power, and the signal-to-noise ratio was monitored via an oscilloscope. Zinc isotopes; Zn-64, Zn-66, and Zn-68 were observed with high resolution within 1 μs by systematically applying electric fields in the ionization and extraction regions. The full-width half maximum (FWHM) significantly decreased with increasing electric field strength, from 0.215 to 0.137 μs for Zn-64, 0.294 to 0.146 μs for Zn-66, and 0.239 to 0.190 μs for Zn-68. The mass concentrations for Zn-64, Zn-66, and Zn-68 were estimated to be 48.6 %, 27.9 %, and 18.8 %, respectively, within ±0.1 % uncertainty, which is in agreement with the reported values in the literature. Laser-induced breakdown spectroscopy (LIBS) is used for plasma characterization and rapid qualitative identification of the constituent elements in the sample under study. Energy-dispersive X-ray (EDX) spectroscopy is applied for the cross-validation of the qualitative results obtained using LIBS. Since spectroscopically pure zinc was used in this study, spectral lines of any impurity elements may also appear in both spectra. However, LA-TOF-MS yields peaks along the arrival time scale of the constituent ions in the sample. The results demonstrate that LA-TOF-MS, combined with LIBS and EDX techniques, suggest a rapid method for elemental/isotope analysis.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"512 ","pages":"Article 117442"},"PeriodicalIF":1.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739756","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 : 2025-03-17DOI: 10.1016/j.ijms.2025.117434
Kenzo Hiraoka , Stephanie Rankin-Turner , Dilshadbek T. Usmanov , Sherzod M. Akhmedov , Satoshi Ninomiya
In our previous work, direct analyses of low-volatility compounds have been performed using Leidenfrost phenomenon-assisted thermal desorption (LPTD). LPTD is affected by several factors such as substrate temperature, solvent properties, liquid volume, and surface-activity value of the analyte. In this work, the effects of surface properties of the metal substrate on LPTD were investigated by using a metal substrate with and without coating the surface with a fluoro compound. A 5 μL aliquot of 0.03 ppm of cocaine or morphine in methanol was dropped on the heater at 240 °C and mass spectra were measured as a function of time. The heater surface was polished with an abrasive agent with grit number of #5000 (alumina powder with ∼3 μm in diameter). When a non-coated metal was used for cocaine and morphine, analyte evaporation was observed only after the complete evaporation of methanol. However, when the metal surface was coated with a fluoro compound, evaporation of surface-active morphine accompanied by the rapid evaporation of methanol was observed. This is due to the rapid temperature rise of the droplet at the last moment of Leidenfrost phenomenon resulting in the occurrence of flash evaporation of morphine. This phenomenon was not observed for non-surface active cocaine.
{"title":"Leidenfrost phenomenon-assisted thermal desorption (LPTD) using a metal substrate coated with a fluoro compound: Mechanism of analyte evaporation","authors":"Kenzo Hiraoka , Stephanie Rankin-Turner , Dilshadbek T. Usmanov , Sherzod M. Akhmedov , Satoshi Ninomiya","doi":"10.1016/j.ijms.2025.117434","DOIUrl":"10.1016/j.ijms.2025.117434","url":null,"abstract":"<div><div>In our previous work, direct analyses of low-volatility compounds have been performed using Leidenfrost phenomenon-assisted thermal desorption (LPTD). LPTD is affected by several factors such as substrate temperature, solvent properties, liquid volume, and surface-activity value of the analyte. In this work, the effects of surface properties of the metal substrate on LPTD were investigated by using a metal substrate with and without coating the surface with a fluoro compound. A 5 μL aliquot of 0.03 ppm of cocaine or morphine in methanol was dropped on the heater at 240 °C and mass spectra were measured as a function of time. The heater surface was polished with an abrasive agent with grit number of #5000 (alumina powder with ∼3 μm in diameter). When a non-coated metal was used for cocaine and morphine, analyte evaporation was observed only after the complete evaporation of methanol. However, when the metal surface was coated with a fluoro compound, evaporation of surface-active morphine accompanied by the rapid evaporation of methanol was observed. This is due to the rapid temperature rise of the droplet at the last moment of Leidenfrost phenomenon resulting in the occurrence of flash evaporation of morphine. This phenomenon was not observed for non-surface active cocaine.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"512 ","pages":"Article 117434"},"PeriodicalIF":1.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681973","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 : 2025-03-17DOI: 10.1016/j.ijms.2025.117435
Abigail M. Friese, Audrey R. Burrows, Scott L. Anderson
Methodology is presented for non-destructive, optically-detected single nanoparticle (NP) mass spectrometry, with the goal of extracting surface reaction kinetics for single NPs at high temperatures. Methods for determining the NP charge, mass, and temperature as a function of time are discussed, and the data are used to extract both the absolute kinetics for mass change, as well as the efficiencies of the surface processes that cause them. Factors that contribute to the uncertainties in absolute and relative mass determination, and in the resulting kinetic parameters, are discussed. The method allows the NP-to-NP variations in initial reactivity to be measured directly, along with the time evolution of reactivity resulting from NP structural/compositional changes that occur under reaction conditions.
The strengths and limitations of single nanoparticle mass spectrometry as a high temperature surface kinetics tool are discussed in the context of sublimation and O2 oxidation kinetics experiments for single hafnium (Hf) NPs at temperatures ranging above 2400 K. The Hf oxidation kinetics are compared to analogous oxidation experiments for silicon, graphite, and carbon black NPs. In all four cases, the oxidation chemistry was dominated by processes that result in net mass loss, and the distinct mechanisms responsible are discussed. All four NPs also eventually passivated, i.e., the efficiencies for oxidative etching decreased by at least two orders of magnitude, relative to the initial efficiencies. The passivation mechanisms, which are quite different for carbon, compared to silicon or hafnium, are discussed. Carbon NP passivation is attributed to structural isomerization leading to fully coordinated, fullerene-like NP surfaces, while for silicon and hafnium, passivation results from delayed formation of an oxide layer, triggered by accumulation of oxygen in the NP sub-surface region.
{"title":"High and ultra-high temperature reaction kinetics by single nanoparticle mass spectrometry","authors":"Abigail M. Friese, Audrey R. Burrows, Scott L. Anderson","doi":"10.1016/j.ijms.2025.117435","DOIUrl":"10.1016/j.ijms.2025.117435","url":null,"abstract":"<div><div>Methodology is presented for non-destructive, optically-detected single nanoparticle (NP) mass spectrometry, with the goal of extracting surface reaction kinetics for single NPs at high temperatures. Methods for determining the NP charge, mass, and temperature as a function of time are discussed, and the data are used to extract both the absolute kinetics for mass change, as well as the efficiencies of the surface processes that cause them. Factors that contribute to the uncertainties in absolute and relative mass determination, and in the resulting kinetic parameters, are discussed. The method allows the NP-to-NP variations in initial reactivity to be measured directly, along with the time evolution of reactivity resulting from NP structural/compositional changes that occur under reaction conditions.</div><div>The strengths and limitations of single nanoparticle mass spectrometry as a high temperature surface kinetics tool are discussed in the context of sublimation and O<sub>2</sub> oxidation kinetics experiments for single hafnium (Hf) NPs at temperatures ranging above 2400 K. The Hf oxidation kinetics are compared to analogous oxidation experiments for silicon, graphite, and carbon black NPs. In all four cases, the oxidation chemistry was dominated by processes that result in net mass loss, and the distinct mechanisms responsible are discussed. All four NPs also eventually passivated, i.e., the efficiencies for oxidative etching decreased by at least two orders of magnitude, relative to the initial efficiencies. The passivation mechanisms, which are quite different for carbon, compared to silicon or hafnium, are discussed. Carbon NP passivation is attributed to structural isomerization leading to fully coordinated, fullerene-like NP surfaces, while for silicon and hafnium, passivation results from delayed formation of an oxide layer, triggered by accumulation of oxygen in the NP sub-surface region.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"512 ","pages":"Article 117435"},"PeriodicalIF":1.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681975","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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