Rapid Communications in Mass Spectrometry最新文献

{"title":"The ‘LSVEC problem’ for the Vienna Peedee belemnite carbon isotope-delta scale","authors":"Philip J. H. Dunn,&nbsp;Federica Camin","doi":"10.1002/rcm.9841","DOIUrl":"10.1002/rcm.9841","url":null,"abstract":"<p>Since 2016 there have been intense discussions within several established communities and networks regarding the consequences of the withdrawal of the LSVEC lithium carbonate reference material for carbon isotope-delta measurement calibration. These include the Isotope Ratio Working Group (IRWG) of the Consultative Committee for the Amount of Substance (CCQM, French: Comité Consultatif pour la Quantité de Matière) of the International Committee of Weights and Measures (CIPM, French: Comité International des Poids et Mesures); participants within the 2016, 2021 and 2024 Technical Meetings on International Atomic Energy Agency (IAEA) stable isotope ratio reference products; and the International Union of Pure and Applied Chemistry's Commission on Isotopic Abundances and Atomic Weights (IUPAC CIAAW) amongst others. The reasons for these intensive discussions relate to the privileged position that LSVEC has occupied for traceability of carbon isotope-delta measurements relative to Vienna Peedee belemnite (VPDB) and the potential implications of its withdrawal for all current and future measurements of carbon isotope-delta values. This perspective summarises the background information regarding the LSVEC material in the context of the VPDB carbon isotope-delta scale. The various proposals to address the LSVEC problem that have been discussed within those committees and networks are also presented. The information herein was used as a foundation for discussions at the 2024 IAEA Consultancy Meetings on the Development of IAEA Stable Isotope Reference Materials and Related Products and on the Definition and Realisation of the Isotopic Delta Scales for Light Elements (22–26 January 2024, Vienna, Austria). A summary of those 2024 meetings and associated outcomes can be found elsewhere.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 17","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9841","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141454225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-accuracy measurement of 36SF5+ signal using an ultrahigh-resolution isotope ratio mass spectrometer","authors":"Xiang Sun,&nbsp;Fengtai Tong,&nbsp;Yongbo Peng,&nbsp;Huiming Bao","doi":"10.1002/rcm.9845","DOIUrl":"10.1002/rcm.9845","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The Δ³⁶S standard deviation measured in a conventional isotope ratio mass spectrometer such as MAT 253 is <i>ca</i> 0.1‰ to 0.3‰. At this precision, it is difficult to resolve the origin of non-mass-dependent sulfur isotope fractionation in tropospheric sulfate aerosol and in Martian meteorites or small deviations from the canonical mass-dependent fractionation laws. Interfering ions with <i>m</i>/<i>z</i> at 131 of ³⁶SF₅⁺ are suggested by the community as the cause of the poor precision, but the exact ion species has not been identified or confirmed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Here we examined the potential interfering ions by using a Thermo Scientific ultrahigh-resolution isotope ratio mass spectrometer to measure SF₆ working gas and SF₆ gases converted from IAEA-S1/2/3 Ag₂S reference materials.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found that there are two resolvable peaks to the right of the ³⁶SF₅⁺ peak when a new filament was installed, which are ¹⁸⁶WF₄²⁺ followed by ¹²C₃F₅⁺. However, only the ¹²C₃F₅⁺ interference peak was observed after more than three days of filament use. ¹²C₃F₅⁺ is generated inside the instrument during the ionization process. Avoiding the interfering signals, we were able to achieve a Δ³⁶S standard deviation of 0.046‰ (<i>n</i> = 8) for SF₆ zero-enrichment and 0.069‰ (<i>n</i> = 8) for overall measurement start from silver sulfide IAEA-S1.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Aging the filament with SF₆ gas can avoid the interference of ¹⁸⁶WF₄²⁺. Minimizing the presence of carbon-bearing compounds and avoiding the interfering signals of ¹²C₃F₅⁺ from ³⁶SF₅⁺, we can improve Δ³⁶S measurement accuracy and precision, which helps to open new territories for research using quadruple sulfur isotope composition.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 17","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141454221","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":"Analysis of mutation-originated gain-of-glycosylation using mass spectrometry-based N-glycoproteomics","authors":"Hailun Yang,&nbsp;Zhixin Tian","doi":"10.1002/rcm.9838","DOIUrl":"10.1002/rcm.9838","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>A general N-glycoproteomics analysis pipeline has been established for characterization of mutation-related gain-of-glycosylation (GoG) at intact N-glycopeptide molecular level, generating comprehensive site and structure information of N-glycosylation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study focused on mutation-originated GoG using a mass spectrometry-based N-glycoproteomics analysis workflow. In brief, GoG intact N-glycopeptide databases were built, consisting of 2701 proteins (potential GoG N-glycosites and amino acids derived from MUTAGEN, VARIANT and VAR_SEQ in UniProt) and 6709 human N-glycans (≤50 sequence isomers per monosaccharide composition). We employed the site- and structure-specific N-glycoproteomics workflow utilizing intact N-glycopeptides search engine GPSeeker to identify GoG intact N-glycopeptides from parental breast cancer stem cells (MCF-7 CSCs) and adriamycin-resistant breast cancer stem cells (MCF-7/ADR CSCs).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>With the criteria of spectrum-level false discovery rate control of ≤1%, we identified 87 and 94 GoG intact N-glycopeptides corresponding to 37 and 35 intact N-glycoproteins from MCF-7 CSCs and MCF-7/ADR CSCs, respectively. Micro-heterogeneity and macro-heterogeneity of N-glycosylation from GoG intact N-glycoproteins with VAR_SEQ and VARIANT were found in both MCF-7 CSCs and MCF-7/ADR CSCs systems.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The integration of site- and structure-specific N-glycoproteomics approach, conjugating with GoG characterization, provides a universal workflow for revealing comprehensive N-glycosite and N-glycan structure information of GoG. The analysis of mutation-originated GoG can be extended to GoG characterization of other N-glycoproteome systems including complex clinical tissues and body fluids.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 17","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141454270","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":"On-site analysis and rapid identification of citrus herbs by miniature mass spectrometry and machine learning","authors":"Xingyu Wang,&nbsp;Yanqiao Xie,&nbsp;Jinliang Yu,&nbsp;Ye Chen,&nbsp;Yun Tian,&nbsp;Ziying Wang,&nbsp;Zhengtao Wang,&nbsp;Linnan Li,&nbsp;Li Yang","doi":"10.1002/rcm.9780","DOIUrl":"10.1002/rcm.9780","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Natural medicines present a considerable analytical challenge due to their diverse botanical origins and complex multi-species composition. This inherent complexity complicates their rapid identification and analysis. Tangerine peel, a product of the <i>Citrus</i> species from the Rutaceae family, is widely used both as a culinary ingredient and in traditional Chinese medicine. It is classified into two primary types in China: Citri Reticulatae Pericarpium (CP) and Citri Reticulatae Pericarpium Viride (QP), differentiated by harvest time. A notable price disparity exists between CP and another variety, Citri reticulatae “Chachi” (GCP), with differences being based on the original variety.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study introduces an innovative method using portable miniature mass spectrometry for swift on-site analysis of QP, CP, and GCP, requiring less than a minute per sample. And combined with machine learning to differentiate the three types on site, the method was used to try to distinguish GCP from different storage years.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>This novel method using portable miniature mass spectrometry for swift on-site analysis of tangerine peels enabled the characterization of 22 compounds in less than one minute per sample. The method simplifies sample processing and integrates machine learning to distinguish between the CP, QP, and GCP varieties. Moreover, a multiple-perceptron neural network model is further employed to specifically differentiate between CP and GCP, addressing the significant price gap between them.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The entire analytical time of the method is about 1 minute, and samples can be analyzed on site, greatly reducing the cost of testing. Besides, this approach is versatile, operates independently of location and environmental conditions, and offers a valuable tool for assessing the quality of natural medicines.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417083","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":"Development of a quantum cascade laser absorption spectrometer for simultaneous measurement of 13C–18O and 18O–18O clumping in CO2","authors":"Scott T. Wieman,&nbsp;Jason Kapit,&nbsp;Anna P. M. Michel,&nbsp;Weifu Guo","doi":"10.1002/rcm.9836","DOIUrl":"10.1002/rcm.9836","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Dual clumped isotope paleothermometry determines carbonate formation temperatures by measuring the frequency of ¹³C–¹⁸O (∆₆₃₈) and ¹⁸O–¹⁸O (∆₈₂₈) pairs in carbonates. It resolves isotopic kinetic biases and thus enables more accurate paleotemperature reconstructions. However, high-precision measurements of ¹⁸O–¹⁸O clumping using current techniques requires large sample sizes and long acquisition times.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We developed a mid-infrared isotope ratio laser spectrometer (IRLS) for simultaneous measurement of the isotopologue ratios ∆₆₃₈ and ∆₈₂₈ in gas-phase carbon dioxide (CO₂) at room temperature. Our IRLS uses a single laser scanning from 2290.7 to 2291.1 cm⁻¹ and a 31 m pathlength optical cell, and it simultaneously measures the five isotopologues required for calculating ∆₆₃₈ and ∆₈₂₈: ¹⁶O¹²C¹⁶O, ¹⁶O¹³C¹⁶O, ¹⁶O¹²C¹⁸O, ¹⁶O¹³C¹⁸O, and ¹⁸O¹²C¹⁸O. In addition, our IRLS can measure ¹⁶O¹²C¹⁷O, enabling ∆¹⁷O analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>At ~20°C and a CO₂ pressure of ~2 Torr, our IRLS system achieved precisions of 0.128‰ and 0.140‰ within 20 s for abundances of the clumped isotopologues ¹⁶O¹³C¹⁸O and ¹⁸O¹²C¹⁸O, respectively, and precisions of 0.267‰, 0.245‰, and 0.128‰ for ¹⁶O¹²C¹⁶O, ¹⁶O¹³C¹⁶O, and ¹⁶O¹²C¹⁸O. This yielded precisions of 0.348‰ (∆₆₃₈) and 0.302‰ (∆₈₂₈) within 25 s. Simulated sample–reference switching highlights the potential of our system and the need for further development.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We demonstrated simultaneous measurements of ∆₆₃₈ and ∆₈₂₈ in CO₂ to precisions of &lt;0.35‰ within 25 s using a room-temperature, single-laser IRLS. Future developments on better resolving ¹⁶O¹²C¹⁶O and ¹⁶O¹³C¹⁶O peaks and system temperature control could further improve the measurement precision.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9836","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitive detection of oxytocin in nonhuman primate plasma using a novel liquid chromatography–tandem mass spectrometry assay","authors":"Kristopher M. Fecteau,&nbsp;Tatiana A. Shnitko,&nbsp;Kathleen A. Grant,&nbsp;David W. Erikson","doi":"10.1002/rcm.9839","DOIUrl":"10.1002/rcm.9839","url":null,"abstract":"","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417085","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":"Data-independent acquisition combined with liquid chromatography mass spectrometry technique to detect prognostic protein markers in type I gastric neuroendocrine neoplasm","authors":"Meng Zhang,&nbsp;Xiuli Zheng,&nbsp;Chunyan Wang,&nbsp;Shengmian Li","doi":"10.1002/rcm.9849","DOIUrl":"10.1002/rcm.9849","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>This study used proteomics-based data-independent acquisition (DIA) technology with the aim of screening for differential expression proteins in type I gastric neuroendocrine neoplasm (g-NEN).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Differential expression proteins in type I g-NEN and peritumoral tissues were screened using DIA with liquid chromatography/tandem mass spectrometry (DIA-LC/MS/MS). The identified proteins were then functionally analysed using bioinformatics methods. We selected the three most highly expressed proteins, combined with patients' clinical data, for prognostic analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Compared with peritumoral tissues, 224 proteins were up-regulated, and 70 were down-regulated. The most significantly enriched biological processes and pathways were vacuolar proton-transporting V-type ATPase complex assembly and metabolism-related pathways. PCSK1, FBXO2, ACSL1, IRS2, and PTPRZ1 expression was markedly up-regulated in type I g-NENs. High IRS2 expression significantly correlated with a shorter time to recurrence.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our study provides a comprehensive proteomic signature based on DIA-LC/MS/MS and highlights high IRS2 expression as a potential prognostic marker for type I gNENs.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417077","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":"Lipid extraction alters amino acid composition and bulk, but not amino acid, carbon and nitrogen isotope values","authors":"Kelton W. McMahon","doi":"10.1002/rcm.9848","DOIUrl":"10.1002/rcm.9848","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Concerns exist over observed shifts in value and variance of nitrogen isotopes following physicochemical extraction of lipids from organic matter. The mechanisms behind these apparent changes in bulk tissue δ¹⁵N values are not fully understood yet have major implications for analytical costs and integrity of data interpretations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Changes in proximate analysis, amino acid composition, C:N ratios, bulk tissue and amino acid δ¹³C and δ¹⁵N values, and resulting isotope-based food web metrics were compared between lipid-intact and lipid-extracted muscle tissue of fishes spanning &lt;1% to &gt;20% muscle fat content to identify mechanisms of nitrogen isotope fractionation associated with physicochemical lipid extraction.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Bulk δ¹³C and δ¹⁵N values increased and %N, C:N ratios and crude protein content decreased following lipid extraction. Resulting bulk isotope niche spacing and overlap varied significantly between lipid-intact and lipid-extracted tissues. While amino acid composition significantly changed during lipid extraction, particularly for lipid-associated amino acids (e.g., Glu, Lys, Ser), individual amino acid δ¹³C and δ¹⁵N values, and their associated compound-specific isotope analysis of amino acids (CSIA-AA)-based food web metrics, did not.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Physicochemical lipid extraction caused significant tissue composition changes (e.g., leaching of amino acids and ¹⁵N-deplete nitrogenous waste) that affected δ¹³C and δ¹⁵N values and tissue %C and %N beyond simply removing lipids. However, lipid extraction did not alter individual amino acid δ¹³C or δ¹⁵N values or their associated CSIA-AA-based food web metrics.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9848","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the impurity profiles of cloxacillin and flucloxacillin based on liquid chromatography tandem ion trap/time-of-flight mass spectrometry","authors":"Bingyong Xu,&nbsp;Jiarui Gao,&nbsp;Jian Wang,&nbsp;Fan Wang","doi":"10.1002/rcm.9840","DOIUrl":"10.1002/rcm.9840","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Cloxacillin and flucloxacillin are prone to degradation and polymerization in humid and hot environments, and their polymers have long been recognized to trigger allergic manifestations. A series of the degradation and polymerized impurities in cloxacillin and flucloxacillin were separated and characterized to ensure safe use of these drugs by the public.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>By studying the chromatographic behavior of the degradation impurities and polymerized impurities in reversed-phase high-performance liquid chromatography (RP-HPLC) gradient elution, the impurities in cloxacillin and flucloxacillin were effectively separated and eluted. RP-HPLC tandem ion trap/time-of-flight mass spectrometry (MS) was applied to characterize the structures of unknown impurities eluted from the RP-HPLC methods for cloxacillin and flucloxacillin. The mechanisms of formation of the impurities in cloxacillin and flucloxacillin were also investigated.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The structures of 10 unknown impurities in cloxacillin and 8 unknown impurities in flucloxacillin were elucidated based on the high-resolution MSⁿ data at positive and negative modes, respectively. Six polymerized impurities were found and characterized, of which three were from the polymerization of cloxacillin and three were from the polymerization of flucloxacillin.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The study on the impurity profiles of cloxacillin and flucloxacillin provided a scientific basis for improving their production processes and quality control.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417086","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":"Lipid A double bond position determination using ozone and laser-induced dissociation","authors":"Abanoub Mikhael,&nbsp;Helena Pětrošová,&nbsp;Derek Smith,&nbsp;Robert K. Ernst,&nbsp;David R. Goodlett","doi":"10.1002/rcm.9854","DOIUrl":"10.1002/rcm.9854","url":null,"abstract":"","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 16","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141417081","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}