{"title":"Positively Charged Water Microdroplets Ionize Surrounding Gas Molecules","authors":"Yuanyi He, Yifan Meng and Richard N. Zare*, ","doi":"10.1021/jasms.5c00178","DOIUrl":"10.1021/jasms.5c00178","url":null,"abstract":"<p >In electrospray ionization, a liquid solution is passed through a narrow capillary held at high voltage─typically +1 to +5 kV for generating positively charged microdroplets or −1 to −5 kV for negatively charged ones. It has recently been claimed that only negatively charged microdroplets can ionize surrounding gases, whereas positively charged microdroplets cannot. In contrast, we present multiple lines of evidence showing that positively charged water microdroplets are indeed capable of ionizing neutral molecules in their vicinity. Using stabilized nanoelectrospray of deionized water and high-resolution mass spectrometry, we detected ionization products of various neutral species, including oxygen, toluene, and other organic vapors. These results indicate that like their negatively charged counterparts, positively charged microdroplets can induce gas-phase ionization involving the loss of an electron from a neutral precursor, likely facilitated by the intense electric field at the microdroplet water–gas interface.</p>","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 9","pages":"1856–1859"},"PeriodicalIF":2.7,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144854160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paul Löffler, Svante Rehnstam, Lutz Ahrens, Foon Yin Lai and Alberto Celma*,
{"title":"Long-Term System Suitability Evaluation for Mass Accuracy in the Analysis of Small Molecules by High-Resolution Mass Spectrometry","authors":"Paul Löffler, Svante Rehnstam, Lutz Ahrens, Foon Yin Lai and Alberto Celma*, ","doi":"10.1021/jasms.5c00128","DOIUrl":"10.1021/jasms.5c00128","url":null,"abstract":"<p >High-resolution mass spectrometry (HRMS) is critical for the identification and characterization of (un)known organic chemicals. In this regard, ensuring high mass accuracy in HRMS instruments is essential for reliable results in nontarget and suspect screening. This study presents a practical approach for evaluating and maintaining mass accuracy over time using ultrahigh pressure liquid chromatography coupled with electrospray ionization Orbitrap HRMS. A set of 13 reference standards, encompassing a range of polarities and chemical families, was analyzed before and after sample analysis batches to assess the impact of various factors on the instrumental performance regarding mass accuracy. The aim is not to recalibrate the system but to provide a reliable snapshot of the mass accuracy over time. The study found that the positive ionization mode exhibited higher accuracy and precision compared with the negative mode. Factors affecting mass accuracy included calibration quality, the number of batch injections, and the time between calibrations, where the two latter factors were related to each other. Results suggest that performing system suitability tests for high-resolution accurate masses with two injections before and after sample analysis is adequate for ensuring acceptable mass spectrometric performance for robust and reliable HRMS data acquisition, but performing three injections is recommended. This protocol ensures that informed decisions can be made with regard to the mass accuracy, the calibration, and a potential recalibration before HRMS data acquisition is performed.</p>","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 9","pages":"2005–2012"},"PeriodicalIF":2.7,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00128","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144833684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yufang Zheng*, Edward P. Erisman, Weihua Ji, Stephen E. Stein and William E. Wallace,
{"title":"Unusual Fragmentations of Silylated Polyfluoroalkyl Compounds Induced by Electron Ionization","authors":"Yufang Zheng*, Edward P. Erisman, Weihua Ji, Stephen E. Stein and William E. Wallace, ","doi":"10.1021/jasms.5c00185","DOIUrl":"10.1021/jasms.5c00185","url":null,"abstract":"<p >Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent compounds that present analytical challenges due to their stability and low concentrations. In this study, electron ionization (EI) mass spectra of trimethylsilyl (TMS) derivatized fluorinated alcohols and carboxylic acids were examined to improve PFAS identification in the NIST Mass Spectral Reference Library. In contrast with the spectra of unsubstituted alcohol TMS compounds featuring losses of hydrocarbons, fluorinated alcohol TMS derivatives are characterized by the losses of fluorinated silyl groups. For example, a previously unreported [M–111]<sup>+</sup> ion was consistently observed in compounds containing three methylene groups between the hydroxyl group and the first CF<sub>2</sub> unit. Detailed quality assurance analysis using a suite of NIST software tools along with high-resolution TOF-MS confirmed the origin and elemental composition of these ions. MS<sup>2</sup> experiments and full scan of TMS derivatives of fluorinated alcohols with varying numbers of methylene groups investigations suggest the formation of a five-membered ring intermediate as a key feature in this unique fragmentation pathway. These findings improve our understanding of PFAS fragmentation and support more accurate compound identification in analytical workflows.</p>","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 9","pages":"1970–1978"},"PeriodicalIF":2.7,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144820316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jingwei Zhang, Zicong Wang, Yuan Liu, Henrik Zetterberg and Lingjun Li*,
{"title":"Boosting Quantification of N-Glycans by an Enhanced Isobaric Multiplex Reagents for Carbonyl-Containing Compound (SUGAR) Tagging Strategy","authors":"Jingwei Zhang, Zicong Wang, Yuan Liu, Henrik Zetterberg and Lingjun Li*, ","doi":"10.1021/jasms.5c00153","DOIUrl":"10.1021/jasms.5c00153","url":null,"abstract":"<p >Glycans are complex molecules composed of various monosaccharides and exhibit diverse, branched polymer structures. Extensive research has been conducted on mass spectrometry (MS)-based qualitative and quantitative glycan analysis due to their critical biological functions. However, traditional data-dependent acquisition (DDA) in MS analysis primarily selects a limited subset of abundant ions during MS1 scans for fragmentation in subsequent MS2 stages. In this study, we introduce an advanced isobaric labeling strategy that incorporates a large amount of content-relevant sample labeled with one isobaric tag channel as an additional boosting channel. This innovation enhances the efficiency of isobaric multiplex reagents for carbonyl-containing compound (SUGAR) tagging in quantitative glycomics. Notably, this approach significantly improves the characterization of low-abundance N-glycans and enables the detection of subtle quantitative differences in N-glycan profiling.</p>","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 9","pages":"1912–1920"},"PeriodicalIF":2.7,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144820315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Keaton L. Mertz, Lia R. Serrano, Pavel Sinitcyn* and Joshua J. Coon*,
{"title":"Dynamic Quadrupole Selection to Associate Precursor Masses with MS/MS Products in Data-Independent Acquisition","authors":"Keaton L. Mertz, Lia R. Serrano, Pavel Sinitcyn* and Joshua J. Coon*, ","doi":"10.1021/jasms.5c00110","DOIUrl":"10.1021/jasms.5c00110","url":null,"abstract":"<p >Data-independent acquisition (DIA) mass spectrometry facilitates high-throughput, reproducible bottom-up proteomic analyses. Typically, DIA methods coselect multiple precursor ions within a wide selection window. These precursors are simultaneously fragmented, superimposing the product ion signals into a complex chimeric spectrum. A method for varying the quadrupole selection width over the ion accumulation period is described. This method couples the intensity of a product ion to the mass of its precursor ion. By overlapping consecutive selection windows, scan-to-scan product ion intensity profiles can be used to infer precursor mass. We assess the method’s sensitivity to quadrupole width, accumulation time, and mass-to-charge range using internal fluoranthene calibrant and FlexMix calibration solution with Q-Orbitrap configured mass analyzers. Additionally, we explore usability of the described technique on a tryptic-digest monoclonal antibody sample, including both direct infusion and liquid chromatography of the sample. With direct infusion, product ions from two precursors separated by 1 thomson (Th) are resolved with this method using 10 Th windows with 5 Th overlap. The product ions are associated within 0.3 Th of their respective precursor ion’s <i>m</i>/<i>z</i>. Therefore, product ion spectra have a precursor ion <i>m</i>/<i>z</i> resolving power of ∼33.</p>","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 9","pages":"1869–1876"},"PeriodicalIF":2.7,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144803223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaokang Guan, Chencheng Wei, Xiaowen Yan* and Renato Zenobi*,
{"title":"","authors":"Xiaokang Guan, Chencheng Wei, Xiaowen Yan* and Renato Zenobi*, ","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 8","pages":"XXX-XXX XXX-XXX"},"PeriodicalIF":2.7,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144779222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"","authors":"Maggie Tam, and , Francisco Fernandez-Lima*, ","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 8","pages":"XXX-XXX XXX-XXX"},"PeriodicalIF":2.7,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00131","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144779228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alandra Quinn*, Kenneth J. Dirico, Simon Berritt, Thomas R. Covey, Jamie Tourville, Brendon Kapinos, Bhagyashree Khunte, Pablo Trigo-Mourino, Hui Zhang, Matthew D. Troutman and Chang Liu*,
{"title":"","authors":"Alandra Quinn*, Kenneth J. Dirico, Simon Berritt, Thomas R. Covey, Jamie Tourville, Brendon Kapinos, Bhagyashree Khunte, Pablo Trigo-Mourino, Hui Zhang, Matthew D. Troutman and Chang Liu*, ","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 8","pages":"XXX-XXX XXX-XXX"},"PeriodicalIF":2.7,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00182","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144779240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tatsuya Sakamoto, Natsuki Iida, Tomokazu Furukawa, Mayu Onozato and Takeshi Fukushima*,
{"title":"","authors":"Tatsuya Sakamoto, Natsuki Iida, Tomokazu Furukawa, Mayu Onozato and Takeshi Fukushima*, ","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 8","pages":"XXX-XXX XXX-XXX"},"PeriodicalIF":2.7,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144779217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"","authors":"Mitsuo Takayama*, and , Hirokazu Takanashi, ","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 8","pages":"XXX-XXX XXX-XXX"},"PeriodicalIF":2.7,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00127","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144779234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}