Rapid Communications in Mass Spectrometry最新文献

{"title":"Potential Biomarkers for Neurobrucellosis Diagnosis and Treatment Based on Cerebrospinal Fluid Metabolomics Analysis","authors":"Meiling Liu,&nbsp;Shujun Shi,&nbsp;Yuzhou Guo,&nbsp;Menghan Lv,&nbsp;Xuan Feng,&nbsp;Ting Liu,&nbsp;Hao Yang,&nbsp;Zhelin Zhang","doi":"10.1002/rcm.9946","DOIUrl":"10.1002/rcm.9946","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Zhenzhu Tongluo pills (ZZTL) have been utilized for the treatment of neurobrucellosis (NB) in the Inner Mongolia region of China. However, the specific mechanism underlying the neuroprotective effects of ZZTL in NB remains insufficiently explored. Therefore, this study aimed to analyze the metabolite profiles across different groups to identify potential biomarkers for the diagnosis and treatment of NB.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>LC–MS analysis was used to screen differential metabolites in cerebrospinal fluid (CSF) samples from control subjects, NB patients, and NB patients undergoing ZZTL therapy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We identified 225 common metabolites across two comparison groups (NB vs. control group and NB + ZZTL vs. NB group). Among these metabolites, 138 were downregulated, and 87 were upregulated in the NB group compared to the control group, while the levels of these metabolites were reversed by ZZTL therapy. Creatinine exhibited the highest VIP score in both comparison groups, with elevated levels observed in CSF samples from NB patients compared to controls; however, its levels were reduced following ZZTL therapy. Additionally, hypoxanthine and uric acids levels were also increased in CSF samples from NB patients, indicating dysregulation of purine metabolism in NB; however, these changes were reversed by ZZTL. Furthermore, pantothenic acid (vitamin B5) and niacinamide (vitamin B3) levels were decreased in CSF samples from NB patients, suggesting a potential link between NB and vitamin B3 and B5 deficiency; however, these changes were reversed by ZZTL.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Collectively, CSF metabolomics may effectively differentiate NB patients from control subjects, providing valuable insights for NB diagnosis and treatment.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724399","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":"Tandem Mass Spectrometry of Perfluorocarboxylate Anions: Fragmentation Induced by Reactive Species Formed From Microwave Excited Hydrogen and Water Plasmas","authors":"Jack G. Li,&nbsp;Chris J. Bowen,&nbsp;Bun Chan,&nbsp;Hidenori Takahashi,&nbsp;Richard A. J. O'Hair","doi":"10.1002/rcm.9953","DOIUrl":"https://doi.org/10.1002/rcm.9953","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Polyfluoroalkyl substances (PFAS) like perfluorooctanoic acid have persistent environmental and physiological effects. This study investigates the degradation of C_nF_2n+1CO₂⁻ (<i>n</i> = 1–7) with neutral radical fragmentation under oxygen attachment dissociation (OAD). Unique fragments absent from collision-induced dissociation (CID) are observed. Further, potential mechanisms are uncovered by density functional theory (DFT) calculations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>From a standard mixture of PFAS, straight-chain perfluorinated carboxylic acids with carbon chain lengths of one to eight were separated via liquid chromatography and transferred to the gas phase via negative-mode electrospray ionisation. Each C_nF_2n+1CO₂⁻ of interest was mass selected and fragmented via both CID and OAD in a quadrupole time-of-flight mass spectrometer. DFT optimisations of structures were performed at M06/6-31+g(d), and single point energy calculations were performed at M06-2X/aug-cc-pVTZ for C₃F₇CO₂⁻.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Decarboxylation was observed from both CID and OAD, but fluorine abstraction and hydroxyl addition only occurred with OAD. The DFT calculations suggest that C₃F₆^–• (<i>m</i>/<i>z</i> 150) is most likely formed from by H• attack onto a β- C-F bond, then loss of HF, finally decarboxylation. Further, C₃F₅O⁻ (<i>m</i>/<i>z</i> 147) likely arises from C₃F₆^–• recombining with OH• to produce energised C₃F₆OH⁻ ions, followed by α- or β- elimination of HF to give enolate and/or epoxide-type products.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>OAD of C₃F₇CO₂⁻ yields unique product ions C₃F₆^–• (<i>m</i>/<i>z</i> 150) and C₃F₅O⁻ (<i>m</i>/<i>z</i> 147) absent from collision-induced dissociation. DFT calculations suggest an intricate pathway of H• attack onto a β C-F bond, then loss of HF, decarboxylation, recombination with OH•, and finally α- or β- elimination of HF to give the products.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724214","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 Identification of Chemical Constituents in New Compound Aloe Capsule Based on UPLC-Q-Orbitrap-MS","authors":"Siyue Chen,&nbsp;Yajie Dou,&nbsp;Shumin Zhang,&nbsp;Huixin Qiu,&nbsp;Huiru Liu,&nbsp;Yanyan Xu,&nbsp;Lexin Shu,&nbsp;Yubo Li","doi":"10.1002/rcm.9944","DOIUrl":"10.1002/rcm.9944","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The chemical composition of the new compound aloe capsule (NCAC) has not been fully elucidated to date, which poses challenges for pharmacology, scientific, and rational drug use. In this study, a rapid and sensitive method was established to comprehensively study the constituents in the NCAC. The contents of the NCAC were analyzed by UPLC-Q-Orbitrap-MS and data postprocessing technology.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Firstly, the extract was separated by UPLC system, and the fragment information was obtained under positive and negative ions and then compared with the characteristic fragments described in the literature, so as to achieve the purpose of rapid identification of the compound of NCAC.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>A total of 56 compounds including 21 chromones, 6 pyranones, 7 anthraquinones, 7 anthrone, 5 alkaloids, 4 amino acids, and 6 other components were detected in NCAC by comparing the retention time and mass spectrometry information and retrieving the reference literature.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The UPLC-Q-Orbitrap-MS method was developed and utilized successfully to identify the major constituents in NCAC and would be helpful for improving the quality control standard of NCAC.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714922","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":"Large-Volume Injection and Assessment of Reference Standards for n-Alkane δD and δ13C Analysis via Gas Chromatography Isotope Ratio Mass Spectrometry","authors":"Paul D. Zander,&nbsp;Florian Rubach,&nbsp;Alfredo Martínez-García","doi":"10.1002/rcm.9943","DOIUrl":"10.1002/rcm.9943","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Compound-specific stable isotope analysis of hydrogen (δD) and carbon (δ¹³C) in organic compounds is a valuable tool in biogeochemical research. A key limitation of this method is the relatively large amount of sample required to achieve desirable precision.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We developed a large-volume (20 μL) injection method that allows for high throughput analysis of less concentrated samples and tested it for δ¹³C and δD measurements of <i>n</i>-alkanes. We also conducted a comparison of reference standards and assessed several methods to normalize and correct <i>n</i>-alkane δD and δ13C measurements.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The mean precision of the δD method based on 233 environmental <i>n</i>-alkane samples (two to three replications per sample) is 4.0‰ (1σ, estimated from the weighted mean of the pooled unbiased standard deviations) and 0.46‰ (1σ) for δ¹³C from 37 environmental samples (two to three replications per sample). The evaluation of reference standards shows that the use of <i>n</i>-alkane standards with large offsets in δD values in adjacent <i>n</i>-alkane chains can lead to biases in measurement correction.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The large-volume injection method shows good reproducibility of δ¹³C and δD measurements of <i>n</i>-alkanes and reduces the required sample concentration by about 80%. We propose that for δD measurements, a reference standard set should be used in which each reference standard has a limited range of δD values and no adjacent <i>n</i>-alkane chains, to minimize memory effects.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9943","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714916","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":"Anionic Reactions Degrading SF6 Using Metals: Insights From the Gas Phase","authors":"Shiven Joshi,&nbsp;Sharon Barden,&nbsp;Paul M. Mayer","doi":"10.1002/rcm.9948","DOIUrl":"10.1002/rcm.9948","url":null,"abstract":"<p>Alkali metals have been used to degrade SF₆ in liquid ammonia. The products include metal fluorides. In this study, we reacted K⁻ and Ag⁻ with SF₆ in a triple quadrupole mass spectrometer. The atomic metal anions were formed by in-source collision-induced dissociation (CID) of their respective oxalate salts as previously described by our group. The only two reaction products observed were SF₆⁻ and SF₅⁻. At low collision energy, the latter was deduced to be formed via an abstraction by the metal of F from SF₆⁻ formed by electron transfer in the encounter complex between the metal anion and neutral SF₆. As the collision energy was increased, there was evidence of a CID contribution to SF₅⁻ directly from SF₆⁻.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724392","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":"A Proof-of-Principle Study for δ15N Measurements of Aqueous Dissolved Nitrate With a Modified LC-IRMS Interface","authors":"Tobias Hesse,&nbsp;Felix Niemann,&nbsp;Shaista Khaliq,&nbsp;Daniel Köster,&nbsp;Julian Enss,&nbsp;Christian K. Feld,&nbsp;Milen Nachev,&nbsp;Klaus Kerpen,&nbsp;Maik A. Jochmann,&nbsp;Torsten C. Schmidt","doi":"10.1002/rcm.9950","DOIUrl":"10.1002/rcm.9950","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The analysis of nitrogen isotopes in aqueous dissolved nitrate is an effective method for identifying pollution sources and offers the potential to study the nitrogen cycle. However, the measurement of nitrogen isotope ratios of nitrate still requires extensive sample preparation or derivatization.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this study, a modified commercially available liquid chromatography–isotope ratio mass spectrometer (LC-IRMS) interface is presented that enables automated measurement of <i>δ</i>¹⁵N signatures from nitrate by online reduction of nitrate in two consecutive steps. First, vanadium(III) chloride is used as a reducing agent to convert NO₃⁻ to N_<i>x</i>O_y under acidic conditions. The mix of nitrogen oxides is then transferred into a stream of helium and reduced to nitrogen (N₂) analysis gas via a hot copper reactor. Prior to the online conversion of aqueous nitrate into elemental nitrogen, the sample was chromatographically separated from potential matrix effects on a PGC column.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Precision was achieved at a level below 1.4‰ by injecting 10 μL of 50 mg L⁻¹ N, using five different nitrate standards and reference materials. These materials spanned a range of more than 180‰ in <i>δ</i>¹⁵N. To demonstrate the applicability of the method, we measured water samples from an enrichment experiment, where isotopically enriched ammonium chloride was administered into a small river over the course of 2 weeks. In contrary to our expectation, the δ¹⁵N values of river nitrate showed values between +0.4 ± 0.4‰ and +4.1 ± 0.3‰, varying over a small range of 3.7‰.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our study showed that the measurement of nitrate nitrogen isotope ratios with a modified LC-IRMS system is possible but that further modifications and improvements would be necessary for a robust and user-friendly instrument.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9950","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714782","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":"Same, but different: Variations in fragment ions among stereoisomers of a 17α-methyl steroid in gas chromatography/electron ionization mass spectrometry","authors":"Jakob Steff,&nbsp;Maria K. Parr","doi":"10.1002/rcm.9934","DOIUrl":"https://doi.org/10.1002/rcm.9934","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Gas chromatography/electron ionization mass spectrometry (GC/EI-MS) is a well-established tool for the identification of unknown compounds such as new metabolites of xenobiotics. But it reaches the limits of confident structural assignment if it comes to stereoisomers. This work helps to overcome this difficulty by getting a deeper comprehension of composition of so far unspecific and also characteristic fragment ions in general and comparison among stereoisomers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Unit mass resolution mass spectra of various isotopologues of four 17α-methyl steroid diastereomers obtained by selectively introducing [²H₉]-trimethylsilyl (TMS) groups or chemical syntheses were systematically compared. The impact of stereochemistry on variations of relative abundances has been assessed by statistical comparison from repeated measurements. Additionally, characterization of <i>m/z</i> 318 with high-resolution MS using gas chromatography/quadrupole time-of-flight MS (GC/QTOF-MS) was performed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The formation of fragment ions from TMS-derivatives after cleavage of methyl or TMS groups ([M-CH₃]⁺, [M-TMSOH]^•+, [M-CH₃-TMSOH]⁺, [M-2x90]^•+, [M-2x90-CH₃]⁺) rarely arises from only one position in the molecule and composition of fragment ion signals is highly influenced by the stereochemistry of the A-ring at C3 and C5 of the steroid. Similarly, the formation of the characteristic fragment ion <i>m/z</i> 143 most likely consists of two different ways of formation. A possible structure for fragment ion <i>m/z</i> 318 was postulated.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Stereoisomers showed differing fragmentation behaviors based on their configuration. These observations further illustrate that variations among stereoisomers in EI-MS fragmentation is no random underlying process but instead a pattern which needs to be understood in its complexity. This easily accessible technical approach can be applied on different molecule structures to further investigate the field of isomeric assignment in GC/EI-MS.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 2","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9934","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724247","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":"Using stable oxygen isotope dual-inlet isotope-ratio mass spectrometry to elucidate uranium transport and mixed 230Th/U calcite formation ages at the seminal Devils Hole, Nevada, natural laboratory","authors":"Tyler B. Coplen,&nbsp;Robert R. Seal II,&nbsp;Lauren T. Reid,&nbsp;James A. Jordan,&nbsp;Adam C. Mumford","doi":"10.1002/rcm.9926","DOIUrl":"10.1002/rcm.9926","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Vein calcite in Devils Hole has been precipitating continuously in oxygen-isotope equilibrium at a constant temperature for over 500 000 years, providing an unmatched <i>δ</i>¹⁸O paleoclimate time series. A substantial issue is that coeval calcite (based on matching <i>δ</i>¹⁸O values) has uranium-series ages differing by 12 000 years.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>An unparalleled high-accuracy <i>δ</i>¹⁸O chronology series from continuously submerged calcite was used to correct the published uranium-series ages of non-continuously formed calcite in two cores, cyclically exposed by water-table decline during glacial–interglacial transitions. This method relies on the premise that the <i>δ</i>¹⁸O values of coevally precipitated calcite are identical, allowing matching calcite <i>δ</i>¹⁸O values to establish formation ages.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Exposed calcite can have apparent ages that are 12 000 years too young due to unrecognized uranium mobility and resulting mixed ages identified in over 50 mixed uranium-series ages from previous studies. Secondary uranium in fluids, sourced from the formation or dissolution of porous carbonate deposits (folia) with high uranium-238 (²³⁸U) concentrations, has migrated up to 10 mm into vein calcite.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The continuously submerged Devils Hole <i>δ</i>¹⁸O chronology is not explained by orbital forcing. Rather, this chronology represents a regional climate record in the southern Great Basin of sea-surface-temperature (SST) variations off California, variations that preceded the last and penultimate deglaciations by 5000 to approximately 10 000 years. Temporal discrepancies between the continuously submerged Devils Hole chronology and other regional <i>δ</i>¹⁸O records (e.g., the Leviathan chronology) can be explained by unrecognized cryptic, pernicious uranium mobility, leading to model estimations that may be thousands of years younger than actual ages. Consequently, paleo-moisture availability, water-table, and groundwater recharge models based on these mixed uranium-series ages are too young by as much as 12 000 years. The potential for post-formation uranium addition in subaerial cores and speleothems underscores the need for caution in uranium-series dating, highlighting <i>δ</i>¹⁸O time-series comparisons as a method for identifying mixed ages.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9926","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694936","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":"Identification of the chemical constituents in the leaves and twigs of Nerium oleander by ultrahigh-performance liquid chromatography coupled to quadrupole Orbitrap high-resolution mass spectrometry","authors":"Yun Ling,&nbsp;Jingmou Yu,&nbsp;Yi Huang,&nbsp;Mengmo Chen,&nbsp;Qing Zhang","doi":"10.1002/rcm.9942","DOIUrl":"10.1002/rcm.9942","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p><i>Nerium oleander</i> L. (Apocynaceae) is a medium-sized evergreen flowering tree and is distributed widely in China. Various parts of <i>N. oleander</i> have been used medicinally and are reported to possess a wide range of biological activities, including cardiotonic, cytotoxic, and central nervous system depressant activities. However, there is a lack of in-depth understanding of the chemical constituents in various parts of <i>N. oleander</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>An ultrahigh-performance liquid chromatography coupled to quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) method was developed for the qualitative analysis of the chemical constituents in the leaves and twigs of <i>N. oleander</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>As a result, 50 compounds, including phenolic derivatives, flavonoids, cardenolides, and triterpenoids, were identified in <i>N. oleander</i>. Among them, 50 compounds were identified in the leaves of <i>N. oleander</i>, whereas 25 compounds were identified in the twigs of <i>N. oleander</i>. It is noteworthy that 16 phenolic derivatives and 4 flavonoids were first detected in this plant and 10 cardenolides were deduced as potential new compounds.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study provided an effective method for comprehensively analyzing the complex system of medicinal plants and enriched the chemical compositions in <i>N. oleander</i>.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 2","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142674594","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":"Investigation of the mechanism of [M–H]+ ion formation in photoionized N-alkyl-substituted thieno[3,4-c]-pyrrole-4,6-dione derivatives during higher order MSn high-resolution mass spectrometry","authors":"Salim Sioud,&nbsp;Maan Amad,&nbsp;Zhiyong Zhu,&nbsp;Denis Lesage,&nbsp;Héloïse Dossmann","doi":"10.1002/rcm.9940","DOIUrl":"10.1002/rcm.9940","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The mechanism underlying dopant-assisted atmospheric pressure photoionization's (APPI) formation of ions is unclear and still under debate for many chemical classes. In this study, we reexamined the gas-phase reaction mechanisms responsible for the generation of [M–H]⁺ precursor ions, resulting from the loss of a single hydrogen atom, in a series of <i>N</i>-alkyl-substituted thieno[3,4-<i>c</i>]-pyrrole-4,6-dione (TPD) derivatives.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Atmospheric pressure photoionization combined with higher order MS/MS^<i>n</i> using high-resolution mass spectrometry (APPI-HR-CID-MS^<i>n</i>) and electronic structure calculations using density functional theory were used to determine the chemical structure of observed [M–H]⁺ ions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>As a result, the higher order MS^<i>n</i> (<i>n</i> = 3) experiments revealed a reversed Diels–Alder fragmentation mechanism, leading to a common fragment ion at <i>m</i>/<i>z</i> 322 from the studied [M_1–5–H]⁺ ion species. In addition, the calculation for two chemical structure models (<i>N</i>-alkyl-TPD1 and <i>N</i>-alkyl-TPD5) showed that the fragment structure, resulting from the removal of the hydrogen atom connected to the third carbon atom of the <i>N</i>-alkyl side chain, has a more stable cyclic form compared with the linear one.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The proposed chemical structure of the <i>N</i>-alkyl TPD ion species, following the loss of a single hydrogen atom, was revealed during APPI-HR-CID-MS^<i>n</i> (<i>n</i> = 3) experiments on the [M–H]⁺ species. Hydrogen radical (H^•) abstraction from the alkyl side chain (e.g., hexyl, heptyl, octyl, 2-ethylhexyl, and nonyl) triggered a rearrangement in the radical cation structure of the <i>N</i>-alkyl-TPD derivatives, initiating cyclization and forming a six-membered ring that connects the oxygen atom to the third carbon atom in the alkyl chain. In addition, theoretical calculations supported the APPI-HR-CID-MS^<i>n</i> (<i>n</i> = 3) experiments by demonstrating that the proposed chemical structure, resulting from the intramolecular cyclization of the <i>N</i>-alkyl-TPD ion species, was stable in the presence of chlorobenzene. These findings will aid the structural determination and elucidation of molecules with similar core structures.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 2","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142612718","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}