International Journal of Mass Spectrometry最新文献

{"title":"Effect of the Tyr5 and His6 substituent groups on the zinc affinities and conformational structures of the acetyl-His1-Cys2-Gly3-Pro4-X5-X6-Cys7 heptapeptides","authors":"Richmond A. Adomako,&nbsp;Michael B. Owusu,&nbsp;Rebekah Oberdick,&nbsp;Kwabena N. Senyah,&nbsp;Perfect Asare,&nbsp;Laurence A. Angel","doi":"10.1016/j.ijms.2025.117458","DOIUrl":"10.1016/j.ijms.2025.117458","url":null,"abstract":"<div><div>In this study, we investigate the influence of the Tyr₅ and His₆ substituent groups on the zinc-binding affinities and conformational properties of a series of acetylated heptapeptides, acetyl-His₁-Cys₂-Gly₃-Pro₄-X₅-X₆-Cys₇ focusing on the impacts where X₅-X₆ are either Tyr₅-Gly₆, Tyr₅-His₆, Gly₅-Gly₆, or Gly₅-His₆. Utilizing traveling-wave ion mobility-mass spectrometry and molecular modeling techniques we analyze the zinc binding interactions and peptide coordination behavior. The zinc binding peptides (ZBPs) relative zinc affinities were measured across pH 5 to pH 10 by monitoring the solution-phase formation of the [ZBP+Zn(II)]⁻ complex by utilizing native MS in negative ion mode to preserve the solution-phase binding of Zn(II) to the peptides. Furthermore, their relative gas-phase Zn(II) affinities were measured using competitive threshold collision-induced dissociation (TCID) of the [ZBP+Zn(II)+NTA]⁻ complex, by modeling the two competing dissociation channels: [ZBP+Zn(II)]⁻ + NTA or [Zn(II)+NTA]⁻ + ZBP, where NTA is nitrilotriacetic acid. Our examinations also tested whether there was an effect of the formation of the [ZBP+Zn(II)+NTA]⁻ complexes from solutions at different pHs, before they are electrosprayed into the gas-phase for the TCID analyses. Both solution- and gas-phase measurements predicted the heptapeptide with the Gly₅-His₆ residues had the greatest zinc affinity and that the presence of Tyr₅ and His₆ altered the zinc affinity and induced distinct conformational changes due to changes in the coordination of the zinc. This research enhances our understanding of zinc-peptide interactions, with implications for the design of peptide-based metalloproteins, which may guide the design of novel ZBPs for therapeutic, biotechnological or environmental remediation applications.</div></div>","PeriodicalId":338,"journal":{"name":"International Journal of Mass Spectrometry","volume":"513 ","pages":"Article 117458"},"PeriodicalIF":1.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882961","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}

{"title":"Mass spectrometry structural analysis of intrinsically disordered phosphoproteins","authors":"Carter Lantz ,&nbsp;Muhammad A. Zenaidee ,&nbsp;Denise Tran ,&nbsp;Karl Biggs ,&nbsp;Gal Bitan ,&nbsp;Rachel R. Ogorzalek Loo ,&nbsp;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}

{"title":"Residue-specific pathways in peptide fragmentation: The role of aromatic side chain in a3 ion formation from b3 ion","authors":"A. Emin Atik ,&nbsp;Sila Karaca ,&nbsp;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>₃ ions from model tripeptides under low-energy CID conditions, focusing on the pathway leading to the stable formation of <em>a</em>₃ ions from <em>b</em>₃ 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 <em>a</em>₃ ions upon <em>b</em>₃ 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>₃ 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 <em>(JACS, 2010, 132, 14,766–14779)</em>. We proposed a plausible fragmentation mechanism for the <em>a</em>₃ 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}

{"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 ,&nbsp;Haizhou Wang ,&nbsp;Lei Wang ,&nbsp;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 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.</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}

{"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 ,&nbsp;Shiyu Cheng ,&nbsp;Zhiyang Wei ,&nbsp;Lixin Shan ,&nbsp;Zhangqi Yu ,&nbsp;Teng Yang ,&nbsp;Yongze Gao ,&nbsp;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}

{"title":"Gas phase proton affinities of proline-containing peptides. 2: ProCys, ProMet, ProSer, ProThr, ProTyr, ProPhe, and ProTrp","authors":"Henry Cardwell ,&nbsp;Paul Acoria ,&nbsp;Alexis Brender A Brandis ,&nbsp;Kathy Huynh ,&nbsp;Madeleine Lamb ,&nbsp;Sophie Messinger ,&nbsp;Daria Moody ,&nbsp;Laurel Nicks ,&nbsp;Hao Qian ,&nbsp;Shantanu Rastogi ,&nbsp;Trinh Ton ,&nbsp;Anna Grace Towler ,&nbsp;Mark Valasquez ,&nbsp;Jennifer Poutsma ,&nbsp;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}

{"title":"Cyclic IMS-MS evidence for potential ring opening in collisionally activated sodiated cyclodextrins","authors":"Sudam S. Mane,&nbsp;Easton K. Cox,&nbsp;Cole D. Warner,&nbsp;David V. Dearden,&nbsp;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}

{"title":"Amide bond formation between substances located in two immiscible liquid phases without phase-transfer catalyst","authors":"Xiao-Fei Gao ,&nbsp;Wei Xiao ,&nbsp;Meng Qiu ,&nbsp;Zhi-Gang Cheng ,&nbsp;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}

{"title":"Isotopic analysis of zinc plasma using Laser‒Ablation Time‒of‒Flight mass spectrometer","authors":"Amir Fayyaz ,&nbsp;Muhammad Aslam Baig ,&nbsp;Rizwan Ahmed ,&nbsp;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}

{"title":"Leidenfrost phenomenon-assisted thermal desorption (LPTD) using a metal substrate coated with a fluoro compound: Mechanism of analyte evaporation","authors":"Kenzo Hiraoka ,&nbsp;Stephanie Rankin-Turner ,&nbsp;Dilshadbek T. Usmanov ,&nbsp;Sherzod M. Akhmedov ,&nbsp;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}