Rapid Communications in Mass Spectrometry最新文献

{"title":"Discovering Novel Short- and Medium-Chain Esters of Hydroxy Fatty Acids in Human Fecal Samples Using Untargeted Liquid Chromatography/Mass Spectrometry","authors":"Jayashankar Jayaprakash,&nbsp;Divyavani Gowda,&nbsp;Rachana M. Gangadhara,&nbsp;Shalini Jain,&nbsp;Hariom Yadav,&nbsp;Siddabasave Gowda B. Gowda,&nbsp;Shu-Ping Hui","doi":"10.1002/rcm.10032","DOIUrl":"https://doi.org/10.1002/rcm.10032","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Exploring novel metabolites produced by host gut microbiome communication is crucial for understanding their roles in various disease pathologies. We previously uncovered a novel class of lipids, short-chain fatty acid esters of hydroxy fatty acids (SFAHFAs), in mouse fecal samples and demonstrated their promising physiological functions in mammals. However, the discovery of SFAHFAs in human samples remains unexplored.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study aimed to analyze the SFAHFAs and their structural analogs in human fecal samples using liquid chromatography/mass spectrometry.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We identified 26 isomeric lipid species, including SFAHFAs and novel medium-chain fatty acid esters of hydroxy fatty acids (MFAHFAs). The detected SFAHFAs and MFAHFAs were characterized by accurate mass measurements using MSⁿ analysis. The results were validated by matching the mass spectral fragmentation and retention time with authentic standards. Two new MFAHFAs, enanthic acid and caprylic acid esters of long-chain hydroxy fatty acids (C24 and C26), were detected and characterized for the first time in human fecal samples. Among the 26 isomeric lipid species, SFAHFA 2:0/24:0 or 4:0/22:0 and SFAHFA 2:0/24:1 were most abundant among the saturated and unsaturated SFAHFAs, respectively.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study offers the first insights into detecting and characterizing novel gut microbial lipids in human fecal samples. Further investigations are essential to recognize the metabolism and function of these lipids in the human gut.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707451","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 Determination of Isotopic Purity of Stable Isotope (D, 15N, or 13C)-Labeled Organic Compounds by Electrospray Ionization-High-Resolution Mass Spectrometry","authors":"Chenlong Liang,&nbsp;Lin Ling,&nbsp;Hao-Yang Wang","doi":"10.1002/rcm.10031","DOIUrl":"https://doi.org/10.1002/rcm.10031","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Stable isotope-labeled organic compounds, containing D, ¹⁵N, or ¹³C, have widespread applications in chemistry, biology, environmental science, and agriculture. However, the isotopic purity calculations for these labeled organic compounds are usually complicated, especially in mixed isotopes-labeled scenarios. Herein, the electrospray ionization-high-resolution mass spectrometry (ESI-HRMS) was applied to determine the isotopic purity for stable isotope-labeled organic compounds, containing D, ¹⁵N, or ¹³C.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The representative isotopolog ion with its specific molecular formula was proposed to represent various labeled states. The isotopic purity was calculated using the corrected intensities of representative isotopolog ions by removing the natural isotopic contributions from preceding peaks. A unified equation has been proposed for the calculation of isotopic purity for various labeled situations including D, ¹⁵N, or ¹³C.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Several case studies were presented and our calculated isotopic purities were all consistent with the isotopic purities provided in the certificate. In-source CID method was applied for the labeled compound (molecular weight &gt; 400 u), when the maximum resolution setting was insufficient to differentiate isobaric isotopolog ions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Finally, a workflow with a Python calculation program was summarized for determinations of the isotopic purity for mono isotope-labeled or mixed isotopes-labeled organic compounds, involving D, ¹⁵N, or ¹³C, by using ESI-HRMS to assign the representative isotopolog ions with accurate mass and excluding the isobar interference.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698942","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":"Characterization of Mass Spectrometry Fragmentation Patterns Under Electron-Activated Dissociation (EAD) for Rapid Structure Identification of Nitazene Analogs","authors":"Cui-mei Liu,&nbsp;Bo-yu Huang,&nbsp;Zhen-dong Hua,&nbsp;Wei Jia,&nbsp;Li Zhi-yu","doi":"10.1002/rcm.10030","DOIUrl":"https://doi.org/10.1002/rcm.10030","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationate</h3>\u0000 \u0000 <p>The emergence of synthetic opioids represents a complex and concerning development in the field of new psychoactive substances (NPSs). Nitazene analogs, also known as nitazenes or 2-benzylbenzimidazole derivatives, represent a recently emerging and popular subgroup of opioid receptor agonists. This study's streamlined approach aims to facilitate rapid and accurate structural elucidation of emerging nitazene analogs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Method</h3>\u0000 \u0000 <p>Ultra high-performance liquid chromatography-quadrupole time of flight-mass spectrometry (UHPLC-QTOF-MS) with positive electrospray ionization (ESI) was employed to characterize 11 nitazene analogs. The mass spectrometry fragmentation pathways of the characteristic fragment ions under electron-activated dissociation (EAD) mode for nitazene analogs were determined from the high-resolution MS data.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In the MS¹ spectra under ESI, single-charge protonated molecular ion [M + H]⁺ and double charge ion [M + 2H]²⁺ were detected. The characteristic product ions in the MS² spectra under the EAD mode were double charged free radical fragment ions [M + H]^•2+, which were produced through the removal of one electron from the protonated molecular ions, alkyl amino side chain fragment ions, benzyl side chain fragment ions, methylene amino ions, and fragment ions formed by loss of the alkyl side chain from the protonated molecular ions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The fragmentation pathways of the main fragment ions were elucidated based on the EAD-MS² spectra. Based on the summarized mass spectrometry characteristics of nitazene analogs, a flowchart was developed to guide the structure prediction of novel nitazene derivatives encountered in forensic casework. EAD was recognized as a perfect technique for accurate structure prediction and identification of new emerging nitazene analogs.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143690140","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":"Strategies for Reducing the Homogenization Phenomenon in the Screening of Key Components in Network Pharmacology Based on the Detectability of Components","authors":"Kaiye Peng,&nbsp;Sang Xu,&nbsp;Minpeng Li,&nbsp;Wei Li,&nbsp;Yun Zou,&nbsp;Mingxin Guo,&nbsp;Xia Wu","doi":"10.1002/rcm.10028","DOIUrl":"https://doi.org/10.1002/rcm.10028","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>The ingredients of traditional Chinese medicine (TCM) are complex and diverse and are often identified using the TCM systems pharmacology (TCMSP) database. However, the ingredients in this database exhibit significant homogeneity, which limits the comprehensive understanding of TCM's ingredient diversity and biological activity. Consequently, liquid chromatography–mass spectrometry (LC–MS) has become a key tool for the precise identification of TCM components.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this study, the LC–MS was used to identify the components of a TCM herb. The identified components were then compared with the component data in the TCMSP database. A network pharmacological prediction of the components was subsequently performed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>An analysis of the four herb formula prescriptions (Ganmai Dazao decoction, Bazhen granule, Shaoyao Gancao decoction, and Zixue san) was conducted, revealing significant discrepancies between the LC–MS identification results and the components in the TCMSP database. The database components were found to be highly homogeneous.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This study underscores the pivotal function of LC–MS in the analysis of components of TCM, particularly in addressing issues of database homogeneity. The employment of LC–MS technology enhances the precision of ingredient identification and streamlines the identification of potential pharmacodynamic ingredients, thereby propelling TCM toward a more contemporary standing.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698941","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":"Characterization of Larvicidal Diterpene Resin Acids in Melipona quadrifasciata Geopropolis via LC-ESI-MS/MS, GC–MS and Computational Analysis","authors":"Luís Guilherme Pereira Feitosa,&nbsp;Juliana Massimino Feres,&nbsp;Camila Capel Godinho,&nbsp;Lorena Carneiro Albernaz,&nbsp;Laila Salmen Espindola,&nbsp;Ricardo Vessecchi,&nbsp;Thais Guaratini,&nbsp;Norberto Peporine Lopes","doi":"10.1002/rcm.10025","DOIUrl":"10.1002/rcm.10025","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Dengue, an arboviral disease transmitted by the <i>Aedes aegypti</i> mosquito, is a major global public health problem challenge. Insecticides based on natural products can provide a good alternative to synthetic agents, as they are safer for both the environment and human health. This study evaluated the activity of geopropolis from stingless bees and <i>Apis mellifera</i> bees on <i>Ae. aegypti</i>, using mass spectrometry approaches to identify compounds with larvicidal potential against <i>Ae. aegypti</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The larvicidal activity of propolis from stingless bees and <i>A. mellifera</i>, as well as the <i>Melipona quadrisfasciata</i> geopropolis (a mixture of soil/clay and propolis), was evaluated against <i>Ae. aegypti</i> larvae (Rockefeller strain). ESI-MS/MS analyses were performed using a quadrupole/time-of-flight mass spectrometer for all geopropolis samples, the geopropolis from <i>Melipona quadrifasciata</i> was also analyzed using an ion trap instrument. The ESI-qTOF-MS/MS data were processed in a spectral similarity network using GNPS. Molecular annotation of potential compounds was performed using the <i>in silico</i> tool called NAP. Gas-phase fragmentation mechanisms were proposed in conjunction with computational chemistry studies. Silylated geopropolis samples were also analyzed by GC–MS.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Geopropolis from the stingless bee <i>M. quadrifasciata</i> caused 90% and 100% mortality in <i>Ae. aegypti</i> larvae after 24 and 48 h of exposure, respectively, exhibiting the highest activity. Mass spectrometry-based molecular network approach supported the suggestion of discriminant compounds between active and inactive samples. The combination of NAP predictions with gas-phase reactions from ESI-MS/MS and EI-MS data facilitated the annotation of larvicidal compounds, including diterpene resin acids, such as dehydroabietic acid and its derivatives, abietic acid, and pimaranes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The combination of HPLC-MS/MS and GC–MS data suggests that diterpene resin acids contribute to the larvicidal effect of <i>M. quadrifasciata</i> geopropolis on <i>Ae. aegypti</i>, enhancing our understanding of potentially bioactive natural products against the arbovirus vector.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672933","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":"Surface Ionization of Carbaryl, Papaverine, Cocaine, Morphine, and Triethylamine by Heated Surface-Oxidized Metal Filaments of W, Re, Pd, Mo, Ti, and SUS304 Under Atmospheric Pressure: Ionization Mechanism","authors":"Kenzo Hiraoka,&nbsp;Dilshadbek T. Usmanov,&nbsp;Sherzod M. Akhmedov,&nbsp;Stephanie Rankin-Turner,&nbsp;Satoshi Ninomiya","doi":"10.1002/rcm.10029","DOIUrl":"10.1002/rcm.10029","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The objective of the present study is to investigate the ionization mechanisms for atmospheric pressure surface ionization (APSI).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>APSI of carbaryl, papaverine, cocaine, morphine, and triethylamine using heated surface-oxidized metal filaments of W, Re, Pd, Mo, Ti, and SUS304 were measured by mass spectrometry. Low-volatility analytes dissolved in methanol were desorbed by Leidenfrost phenomenon-assisted thermal desorption and introduced to the heated metal filament used as an emitter. Alkylamine benzene solutions were simply placed 10 mm below the filament.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Carbaryl, papaverine, cocaine, and morphine (M) gave protonated molecules [M+H]⁺ with little fragment ions. Triethylamine (TEA) gave both [TEA+H]⁺ and [TEA−H]⁺.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Because [M+H]⁺ was detected with little [M−H]⁺, which is usually detected as a major ion by vacuum surface ionization (VSI), it was concluded that [M+H]⁺ is formed by the proton transfer reaction between the protonated filament surface and the gas-phase analyte molecules approaching the solid surface. Namely, the heated metal filament acts as a Brønsted acid. This idea is supported by the APSI for TEA.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11927526/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672936","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":"Determination of Free Amino Acid Concentrations in Bovine Plasma Using High-Pressure Liquid Chromatography With Electrospray Ionization Mass Spectrometry Detection","authors":"Laurie A. Reinhardt,&nbsp;Levi Svaren,&nbsp;Ritvik Marathe,&nbsp;Geoffrey I. Zanton,&nbsp;Michael L. Sullivan","doi":"10.1002/rcm.10027","DOIUrl":"https://doi.org/10.1002/rcm.10027","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Quantification of free amino acid concentrations in plasma has become an important tool in monitoring the health of dairy cows and health of their offspring under various management regimes, especially diet. Consequently, it was desirable to develop a robust, accurate, medium-throughput method to quantitate free amino acid concentrations in bovine plasma.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Bovine plasma was deproteinated with methanol and amino acids partially purified using cation exchange resin. Samples were then subjected to precolumn derivatization with phenyl isothiocyanate, followed by high-pressure liquid chromatography with positive electrospray ionization single quadrupole mass spectrometry detection for analysis. The corresponding ¹³C and ¹⁵N labeled amino acids (mass unit difference &gt; 3) were used as internal standards, while deuterium labeled standards were used for other metabolites.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>All 20 amino acids showed linear fits to their individual calibration curves (correlation coefficients &gt; 0.99) with concentration range of amino acids measured from 5 to 600 μM. Coefficient of variation (CV) values for the concentrations measured for all amino acids ranged from 2.0 to 6.7 for intraday aliquots and from 1.0 to 4.6 for interday aliquots with the exception of aspartic acid (11.1 and 12.6 for intraday and interday, respectively).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The use of a stable isotope labeled version of each amino acid analyte as internal standard added to plasma samples at the beginning of the procedure corrected for any losses, instrument variability, and chemistry of derivatization. Use of this method to quantify bovine plasma amino acids will allow better understanding of physiological processes underlying nutritional interventions in dairy production systems and may be more broadly applicable to ruminant and other animal production systems.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 11","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143646079","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":"Dynamic Metabolite Profile Changes in Semen Ziziphi Spinosae During Ripening","authors":"Xi Tian,&nbsp;Sujun Zhang,&nbsp;Liqiang Gu,&nbsp;Wei Tian,&nbsp;Lingdi Liu,&nbsp;Qiang Li,&nbsp;Tao Jiang","doi":"10.1002/rcm.10024","DOIUrl":"https://doi.org/10.1002/rcm.10024","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>In traditional Chinese medicine, <i>Semen Ziziphi Spinosae</i> (SZS) is employed for alleviating conditions such as neurasthenia, sleep disorders, and anxiety. Its therapeutic effects are attributed to an abundance of biologically active compounds. The main objective of this study was the comparative profiling of SZS from different harvest times using a widely targeted metabolomics approach.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>First, UPLC-Q Trap-MS/MS was used for identification of metabolic profile. Then, multivariate statistical analysis and KEGG enrichment analysis were performed to screen out the differential metabolites and related metabolic pathways among different growth stages.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In total, 466 metabolites were identified at three different growth and development stages (T1, T2, and T3) of SZS using UPLC-Q Trap-MS/MS, including 83 flavonoids, 80 phenolic acids, 67 amino acids and derivatives, 56 lipids, 39 nucleotides and derivatives, 38 organic acids, 1 quinone, 6 lignans and coumarins, 53 other metabolites, 10 tannins, 20 alkaloids, and 13 terpenoids. The result of clustering and PCA analyses showed that there was a great difference in metabolites between SZS at three growth stages. Differential metabolites in three comparison groups (T1 vs. T2, T2 vs. T3, and T1 vs. T3) were 195, 104, and 96, respectively. There were 29 common differential metabolites among the three different growth stages of SZS. The contents of important active ingredients (flavonoids and terpenoids) gradually increased during the T1, T2, and T3 stages, indicating that SZS harvested during T3 period was suitable for medicinal use. All the differential metabolites screened were enriched in 11 metabolic pathways, including glycerolipid metabolism, glycerophospholipid metabolism, phenylalanine metabolism, and phenylpropanoid biosynthesis pathway.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study provides a more comprehensive understanding of the dynamic changes in the metabolic profile of SZS, laying a foundation for subsequent development and utilization.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 11","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143646151","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":"A Long-Lasting, High-Stability Reactor System for Compound-Specific Carbon Isotope Analyses","authors":"Ewerton Santos,&nbsp;Bumsoo Kim,&nbsp;Rafael Tarozo,&nbsp;Sarah McGrath,&nbsp;Marcelo Alexandre,&nbsp;Yongsong Huang","doi":"10.1002/rcm.10020","DOIUrl":"https://doi.org/10.1002/rcm.10020","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Compound-specific carbon isotope analysis is an essential technique in environmental, geobiological, ecological, and forensic research. It involves the online conversion of organic compounds separated by gas chromatography (GC) into carbon dioxide before entering a gas source mass spectrometer for carbon isotopic analysis. However, current oxidation interfaces require frequent maintenance or reactor replacement, reducing efficiency and data quality and increasing costs. This study presents a modified oxidation interface to address these issues.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Our oxidation reactor system uses nickel and platinum wires as an oxidant with a constant oxygen flow controlled by an electronic pressure controller (EPC). This system eliminates the need for full-scale re-oxidation after initial activation and differs from systems using constant pressure control gauges that result in variable oxygen flow and carrier gas composition. We performed systematic comparisons of carbon isotope measurements for fatty acid methyl esters (FAMEs) and <i>n</i>-alkanes between our modified system and a commercial reactor system, and betweem systems that use constant pressure and constant flow oxygen supplies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our oxidation interface with a constant flow of oxygen significantly enhances the analytical precision and accuracy of carbon isotope values, as demonstrated by a consistent reduction in the standard deviation of δ¹³C values to below 0.3‰. Importantly, our system has undergone over 5000 injections extending over 9 months during our longest analytical cycle, with no maintenance or user intervention needed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Our novel reactor system with a constant flow supply of auxiliary oxygen gas to the reactor greatly outperforms the conventional reactor system in efficiency, precision, and accuracy. It is virtually maintenance-free and may be dubbed the “forever” reactor, resulting in greatly enhanced analytical efficiency and reduced cost. Our methodology can be implemented on commercial systems with straightforward modifications by users.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 11","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622672","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":"A Simple Approach to Assign Disulfide Connectivity for Ziconotide via Partial Reduction Without Alkylation","authors":"Peize Wu,&nbsp;Yuya Cheng,&nbsp;Weihua Wang,&nbsp;Ming Li","doi":"10.1002/rcm.10026","DOIUrl":"https://doi.org/10.1002/rcm.10026","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Disulfide bond, an important post-translational modification in peptides or proteins, is of great significance for stabilizing the three-dimensional spatial structure of peptides and proteins, maintaining correct folding conformation, and regulating biological activity. The medicinal peptide with unexpected disulfide connectivity might not have efficacy, even induce immunogenicity. Therefore, it is of importance to assign disulfide connectivity for a peptide.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A relatively simple method based on partial reduction without alkylation was developed. For demonstration, ziconotide was chosen as a model establishing the method. After a partial reduction reaction by using tris(2-carboxyethyl)phosphine, the partially reduced ziconotide products containing one disulfide bond were analyzed by liquid chromatography tandem mass spectrometry. The information about the sequence uninvolved in the cyclic structure was obtained by tandem mass spectrometry, which reveals the connectivity of the disulfide bridges forming the cyclic structure.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Based on the results of only two partially reduced products, accurate connectivity of all disulfide bridges in ziconotide was obtained. Six cysteine moieties present in a ziconotide molecule form three disulfide bonds, which could produce 15 possible disulfide isoforms with different disulfide connectivities. The actual disulfide connectivity was easily identified using this novel method.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>A relatively simple method based on partial reduction without alkylation, followed by analysis with liquid chromatography–tandem mass spectrometry, was developed, assigning disulfide connectivity for a disulfide-rich peptide. This method is useful in the quality control of medicinal peptides with an extensive disulfide network.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 11","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622700","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}