Rapid Communications in Mass Spectrometry最新文献

{"title":"HR-MS Analysis of the Covalent Binding of Edaravone to 5-Formylpyrimidine Bases and a DNA Oligonucleotide Containing a 5-Formylcytidine Residue","authors":"Romain Regnault,&nbsp;Mostafa Kouach,&nbsp;Laurence Goossens,&nbsp;Xavier Thuru,&nbsp;Christian Bailly,&nbsp;Jean-François Goossens","doi":"10.1002/rcm.10050","DOIUrl":"https://doi.org/10.1002/rcm.10050","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Edaravone (EDA) is a radical scavenger and an antioxidant drug approved to treat amyotrophic lateral sclerosis and used as a research tool to explore treatment of neurodegenerative diseases and cancers. It is also a reactive agent, known as PMP (1-phenyl-3-methyl-5-pyrazolone), used for the analysis of polysaccharides composition. EDA can react with sugars and aromatic aldehydes. In this context, we have investigated the reactivity of EDA toward the biologically relevant formylated nucleobases, nucleosides, and an oligonucleotide containing a formylated residue.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The formation of both mono- and bis-adducts between EDA and the formylated nucleobases (5-formyluracil (5fU) and 5-formylcytosine (5fC)) or the corresponding nucleosides 5-fdU and 5-fdC was characterized using high-resolution mass spectrometry (HR-MS). Similarly, the covalent binding of EDA to an 8-mer palindromic oligonucleotide d (TATG[*C]ATA) containing a single 5-fdC residue [*C] under physiological conditions was investigated using mass spectrometry.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For the first time, EDA is shown to react with formylated pyrimidines. Covalent and stable adducts were identified. EDA was found to react efficiently with the formylated oligonucleotide to generate mono- and bis-adducts. The rate of formation of the mono-adduct was five times higher than that of the bis-adduct. The reaction of EDA with aldehydic DNA modifications such as 5fU/5fC may have important consequences in terms of gene expression.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These observations raise implications for an epigenetic contribution to the mechanism of action of EDA. The biological implications of our in vitro results are discussed, notably in the frame of neurodegenerative diseases and cancers.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10050","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852944","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":"Improved Methods for High Precision Isotope-Ratio Infrared Laser Spectroscopy of Ecohydrological Waters With Organic Contaminants","authors":"Xinying Ling,&nbsp;Juske Horita","doi":"10.1002/rcm.10052","DOIUrl":"https://doi.org/10.1002/rcm.10052","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Applications of high-precision isotope analysis of ecohydrological water samples such as soil and plant waters with infrared (IR) laser spectrometry have been hampered by spectral interferences of volatile organic compounds.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this study, three methods were tested to remove methanol (MeOH) and/or ethanol (EtOH) added to water for δ²H, δ¹⁸O, and ¹⁷O-excess analysis with Picarro L2140-i: microcombustion module (MCM), pre-treatment with solid-phase extraction (SPE), and pre-treatment with simple MeOH/EtOH combustion (SMEC) method.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The Picarro MCM was not able to combust the alcohols of high concentrations. Hydrophilic–lipophilic balanced (HLB) SPE could adsorb MeOH/EtOH at low concentrations (e.g., 0.1% EtOH). However, its adsorption capacity could be readily exhausted, and adsorbed water on the SPE adsorbents co-elutes and mix with a sample water. The SMEC can successfully combust highly concentrated waters (0.5% MeOH and 1% EtOH) at 450–500 °C, but the alcohol combustion and oxygen isotope exchange with added O₂ could significantly increase δ¹⁸O values (up to 6–7‰) and decrease ¹⁷O-excess (up to 110 per meg) in the presence of a catalyst. The combination of post-analysis corrections of Picarro MCM data (δ²H and δ¹⁸O) and pre-treatment with SMEC method (δ²H and ¹⁷O-excess) can reach the accuracy and precision of ≤3 and ≤2 ‰ (δ²H), ≤0.2 and ≤0.3‰ (δ¹⁸O), and ≤20 and ≤47 per meg (¹⁷O-excess), respectively.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>A strategy of combining the two methods is proposed for high-precision isotope analysis of organic contaminated samples: post-analysis corrections of Picarro MCM data (δ²H and δ¹⁸O) and pre-treatment with SMEC method (δ²H and ¹⁷O-excess). The improved methods in this study can provide sufficient accuracy and precision for isotope analysis of plant and soil waters, which can contribute to the fields of ecohydrology and agricultural sciences.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852667","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":"From Retention Time to Functional Group Assignment: A Chemical Database-Driven Approach for High-Resolution Mass Data of Marine Dissolved Organic Matter","authors":"Fabian Moye,&nbsp;Marlo Bareth,&nbsp;Boris P. Koch,&nbsp;Jan Tebben,&nbsp;Tilmann Harder","doi":"10.1002/rcm.10043","DOIUrl":"https://doi.org/10.1002/rcm.10043","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The high chemodiversity of marine dissolved organic matter (DOM) has challenged identification of singular DOM components. To infer chemical structure features of DOM with accurately determined molecular formulas, we assessed if empirically determined elution properties of stoichiometrically identical isomers obtained from a chemical database would predict features, such as the type and number of functional groups, in structurally unknown DOM isomers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>DOM of different origin (North Sea, Southern Ocean) was analysed by LC-FT-MS using two different mass spectrometry methods. Chromatographic retention of DOM isomers was correlated with calculated retention properties of structurally known isomers in PubChem. A total of 7.7 million chemical identifiers were queried for their computed octanol–water coefficients (logP). The 50 most intense molecular formulas were queried for PubChem structure data files. The number and type of structural features was assigned to logP bins across the DOM elution window, to correlate the contribution of database-derived structure features to retention time of structurally unknown DOM isomers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The intensity-weighted average of logP for C_xH_yO_z in Southern Ocean water, predicted by retention time of all molecular formulas, was in good agreement with logP values stored in PubChem. The comparatively longer retention of the same isomer in North Sea versus Southern Ocean DOM suggests a decoration with fewer alcohol groups and more ring structures and esters. Earlier eluting molecular formulas are more likely to contain rings and alcohols, while later eluting ones are more linear/branched and contain more esters.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We hypothesised DOM isomers belonging to comparatively older Southern Ocean water to elute earlier than young and less degraded molecules present in North Sea water. This hypothesis was verified based on three exemplarily selected molecular formulas cooccurring in all water samples. Our strategy circumvents issues of chimeric fragmentation spectra and furthermore adds retention time as a new physicochemical descriptor of DOM molecules.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 13","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143831206","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":"Thermal Desorption and Extraction Coupled With Gas Chromatography and Mass Spectrometry for the Quantification of Polystyrene Nanoplastic in Pak Choi","authors":"Eric Zytowski,&nbsp;Susanne Baldermann","doi":"10.1002/rcm.10046","DOIUrl":"https://doi.org/10.1002/rcm.10046","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>It has been demonstrated that microplastics and nanoplastics (MNPs) can be found in soil and that MNPs can be taken up by plants. In order to conduct a risk assessment for human consumption, it is necessary to have an estimate of the mass concentration of plastics in crops. A new thermal extraction and desorption coupled with gas chromatography and mass spectrometry (TED-GC/MS) method has been developed for the analysis of polystyrene (PS) in pak choi.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this study, a thermogravimetric analyser (TGA) equipped with a thermal absorption unit (TAU), was coupled with a GC system equipped with a thermal desorption unit (TDU2), a (5%-phenyl)-methylpolysiloxane GC column and a GC/MSD single quadrupole mass spectrometer. The systems were connected via an MultiPurposeSampler (MPS). Samples were pyrolyzed in the TGA; the pyrolysis products were trapped on a PDMS polymer bar, desorbed in the TDU, separated and analysed on the GC/MS system.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The purpose of this study was to investigate the qualitative and quantitative detection of PS MNPs in pak choi. The determined limit of detection (LOD) was 0.09 μg, and the limit of quantification (LOQ) was 0.28 μg PS absolute. Plants treated with 100 nm of particles 19.0 ± 6.7 μg/g DM PS and in the plants treated with 500 nm of particles 64.1 ± 8.6 μg/g DM PS have been found.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study was the first to use a TED-GC/MS method for the detection of PS nanoplastics of different sizes in pak choi and thus provides an important basis for the determination and risk assessment of PS in vegetables.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826965","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":"Advances in Sampling and Analytical Techniques for Single-Cell Metabolomics: Exploring Cellular Heterogeneity","authors":"Xinxin Shen,&nbsp;Fangyuan Zhang,&nbsp;Chunping Tang,&nbsp;Marina Soković,&nbsp;Danijela Mišić,&nbsp;Hongxi Xu,&nbsp;Yang Ye,&nbsp;Jia Liu","doi":"10.1002/rcm.10045","DOIUrl":"https://doi.org/10.1002/rcm.10045","url":null,"abstract":"<div>\u0000 \u0000 <p>Single-cell metabolomics is an emerging and powerful technology that uncovers intercellular heterogeneity and reveals microenvironmental dynamics in both physiological and pathological conditions. This technology enables detailed observations of cellular interactions, providing valuable insights into processes such as aging, immune responses, and disease development. Despite significant advances, the need for detailed discussions on sampling and analytical methods in single-cell metabolomics continues to grow, with increasing focus on selecting the most suitable techniques for diverse research objectives. This review addresses these challenges by exploring key sampling and analytical strategies used in single-cell metabolomics. We focus on three main approaches: the capture and isolation of specific cell types, the precise aspiration of individual cells, and in situ mass spectrometry imaging. These methods are critically assessed to highlight strategies for achieving accurate metabolite detection at the single-cell level across diverse research applications.</p>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 13","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826837","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":"Generalization of the CCS-Mass Equation to Account for Variations in Molecular Density in an Iron-Ligand Complex Growing System.","authors":"Christopher Kune, Johann Far, Sophie Rappe, Jean Haler, Albert Demonceau, Lionel Delaude, Gauthier Eppe, Edwin De Pauw","doi":"10.1002/rcm.10042","DOIUrl":"https://doi.org/10.1002/rcm.10042","url":null,"abstract":"<p><strong>Rationale: </strong>In this work, the CCS-mass trends equation has been revisited to consider apparent changes in the ion density.</p><p><strong>Methods: </strong>The ion mobility-derived collision cross section (IM-derived CCS) of negatively, single-charged Fe(II) and Fe (III) metal centers coordinated with three or four halide or linear alkyl carboxylate ligands generated by electrospray operating in the negative ionization mode were obtained using a T-wave mobility cell.</p><p><strong>Results: </strong>The CCS-mass trends were fitted using the equation CCS = A × mass^Pow (where A is an apparent density parameter and Pow is a shape parameter). Iron-halide complexes led to Pow parameters well below the typical limit of 0.5, which could only be explained by refining the fitting equation using a linear combination of these A and Pow parameters. Their physical meaning is described in terms of mass distribution within the volume of the iron-ligand complex ions.</p><p><strong>Conclusions: </strong>The analysis of the CCS-mass trend of iron-halide and iron-carboxylate complexes allows us to predict the IM-derived CCS and the CCS-mass trends of combinations of iron-halide/carboxylate complexes. The results show no differences in trend between planar trigonal and tetrahedral geometries as described by the valence shell electron pair repulsion (VSEPR) theory.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":" ","pages":"e10042"},"PeriodicalIF":1.8,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143959951","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":"Performance of Cryogenic Adsorbents for Use in Methane Bulk and Clumped Isotope Analysis","authors":"Nico Kueter,&nbsp;Naizhong Zhang,&nbsp;Jan G. C. Meissner,&nbsp;Léna Monnereau,&nbsp;Paul M. Magyar,&nbsp;Lukas Emmenegger,&nbsp;Stefano M. Bernasconi,&nbsp;Joachim Mohn","doi":"10.1002/rcm.10040","DOIUrl":"https://doi.org/10.1002/rcm.10040","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Cryogenic trapping of methane is essential for bulk and clumped isotope analyses, requiring adsorbent materials that enable efficient recovery and preserve isotopic signatures. This study evaluates the performance – capacity, isotopic fractionation, and ease of use – of silica gels, zeolite molecular sieves, and activated carbon under various trapping and desorption conditions. A focus is set on the preservation of methane clumped isotope signatures.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A well-characterized methane reference gas (40 mL) was cryofocused at 77 K in containers filled with silica gels, zeolite molecular sieves (5A and 13X), or activated carbon alongside non-loaded containers. After loading, the containers were warmed in a water bath (21°C–95°C) for various dwell times. The bulk (𝛿D-CH₄ and 𝛿¹³C-CH₄) and clumped (∆¹³CH₃D and ∆¹²CH₂D₂) isotopic composition of the desorbed methane were measured against the untreated reference gas using novel quantum cascade laser absorption spectroscopy (QCLAS).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The best results were achieved with coarse-grained (1–3 mm) silica gels heated to 50°C for at least 5 min or at 21°C–22°C for a minimum of 120 min. Elevated desorption temperatures (80°C–95°C) compromised clumped isotope signatures. Although effective for gas trapping, zeolite molecular sieves, and activated carbon introduced significant bulk and clumped isotopic shifts due to catalytic effects and chromatographic isotopologue separation. Methane cryofocused without adsorbents retained its bulk and clumped isotopic composition without significant fractionation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Among the tested adsorbents, silica gels demonstrated superior performance, preserving δ¹³C-CH₄, δD-CH₄, ∆¹³CH₃D, and ∆¹²CH₂D₂ values close to or within performance targets while offering high adsorption capacity, reproducibility, and ease of regeneration. Adsorbent-free cryotrapping is a viable alternative for sufficiently large methane volumes, where vapor pressure isotope effects (VPIEs) become negligible. However, cryogenic adsorbents remain indispensable for ensuring isotopic accuracy for small sample volumes and high-precision applications.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 13","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818595","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":"Selective Solid Phase Extraction Using a Mixed-Mode Cation Exchange Cartridge Facilitates the Mass Spectrometry Analysis on Dissolved Organic Nitrogen","authors":"Yuanyuan Dong,&nbsp;Wenrui Yao,&nbsp;Yulin Qi,&nbsp;Yufu Han,&nbsp;Chao Ma,&nbsp;Dietrich A. Volmer","doi":"10.1002/rcm.10037","DOIUrl":"https://doi.org/10.1002/rcm.10037","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Dissolved organic nitrogen (DON) is a crucial component in environment, which acts as the largest reservoir of nitrogen and plays a significant role in the nitrogen cycling, pollutant transport, and substrate utilization among various environmental systems. DON exhibits a relatively low concentration in environment, which presents a great challenge for DON detection, and an efficient separation and enrichment lab protocol is required to fully understand its structural and compositional characteristics. However, there is no standard method to extract DON from complex environmental samples efficiently.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The DON was extracted utilizing solid-phase extraction (SPE), with a one-step elution by the Bond Elut PPL cartridge and the Waters HLB cartridge, and a three-step elution by the Waters MCX cartridge. UV-Vis, fluorescence, mass spectrometry (MS), and gas chromatography-nitrogen chemiluminescence detector (GC-NCD) techniques were utilized to investigate and compare the characteristics of DON from the three different SPE strategies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Combined the fluorescence and MS results, it is found that the stepwise extraction using the MCX cartridge exhibits the best recovery of DON for both standard and environmental samples, and its performance is less affected by the chemical interferences such as surfactants during MS analysis. Furthermore, the MCX fraction exhibits the highest number of DON molecular formulas with a low O/C ratio and a high H/C ratio in environmental samples, and such a fraction also shows an enrichment of nitrosamine-type substances.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This work establishes an efficient MCX-SPE protocol to extract and analyze DON, which can be applied to environmental samples straightforward. The presented work provides a theoretical support for the analysis of DON, which facilitates a comprehensive understanding of the chemical composition and environmental effect of nitrogen-containing substances.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 13","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801826","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":"Integrated Element Doping and Standard-Sample Bracketing for Enhanced Fe–Zn Isotope Precision in MC-ICPMS","authors":"Dong-Yong Li,&nbsp;Long Chen,&nbsp;Hai-Ou Gu,&nbsp;Guo-Chao Sun,&nbsp;Jiang-Hong Deng,&nbsp;Sheng-Yao Yu,&nbsp;Yan-Yan Zhao,&nbsp;Yang Zhang,&nbsp;Nan Wang,&nbsp;Xiao-Qiang Guo,&nbsp;Zhi-Shun Zhang,&nbsp;Kai-Xin Feng,&nbsp;Rong-Bin Zhang,&nbsp;San-Zhong Li","doi":"10.1002/rcm.10041","DOIUrl":"https://doi.org/10.1002/rcm.10041","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Standard-sample bracketing (SSB) and element doping are widely used for correcting instrumental mass bias in Fe–Zn isotope analysis using multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). However, the combined effects of analyte concentration and spike-analyte ratios on measurement accuracy remain underexplored.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We developed an improved Fe–Zn isotope analysis method that combines SSB with element doping to mitigate concentration effects. By systematically evaluating Ni/Fe and Cu/Zn ratios (0.1–2.1) and analyte concentrations ranging from 0.1 to 2.0 times the concentration of the bracketing standards, we assessed their influence on isotope precision and accuracy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our findings indicate that, when low-concentration isotopes are accurately quantified, variations in Ni/Fe and Cu/Zn ratios exert minimal influence on measurement precision. Compared to conventional SSB, the combined approach reduces concentration matching constraints by 30%–50%, broadening the acceptable Fe and Zn concentration ranges. Validation using 10 geological reference materials, including 6 from the United States Geological Survey and 4 from the Geological Survey of Japan, confirmed its reliability, with isotopic values aligning with published data within analytical uncertainty.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The combined approach enhances measurement precision and applicability to diverse geological samples, offering a robust method for Fe–Zn isotope studies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 13","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793460","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":"APCI-Multistage Mass Spectrometry Following Liquid Chromatography for Selected 4-Desmethyl-Sterols and Their Deuterium-Labelled Analogues Unveils Characteristic Fragmentation Routes for Cholesterol and Phytosterols Identification","authors":"V. Cinquepalmi,&nbsp;I. Losito,&nbsp;A. Castellaneta,&nbsp;C. D. Calvano,&nbsp;T. R. I. Cataldi","doi":"10.1002/rcm.10039","DOIUrl":"https://doi.org/10.1002/rcm.10039","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Several phytosterols (PSs), well known for their role in plant physiology and their health benefits, represent a subset of the family of 4-desmethyl-sterols. They exhibit remarkable structural variability due to differences in the number and position of C=C bonds in their tetracyclic backbone and side chain composition. When analysed using tandem mass spectrometry (MS/MS), PSs often produce complex and potentially informative spectra, as in the case of electron ionization. However, these spectra have been only partially interpreted so far. Here, a systematic interpretation of the fragmentation of PSs, specifically free sterols, was pursued through a synergic use of high- and low-resolution multistage mass spectrometry (MSⁿ, <i>n</i> = 2–4).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The study focused on protonated and dehydrated forms of standard 4-desmethyl-sterols ([M + H-H₂O]⁺), generated via atmospheric pressure chemical ionization (APCI) following reversed-phase liquid chromatography (RPLC). Deuterium-labelled versions of cholesterol and stigmasterol, appropriately labelled on their side chains, were examined alongside their natural counterparts and other key PS standards, including β-sitosterol, campesterol, brassicasterol, Δ⁵-avenasterol (isofucosterol) and its isomer Δ⁷-avenasterol.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The use of isotopically labelled standards allowed the identification of diagnostic, low <i>m/z</i>, product ions associated with the side chain, demonstrating that the positive charge can localize not only at the C3 position (associated with the hydroxyl group) but also on the side chain itself (C24/C25). Furthermore, all remaining peak signals in the tandem MS spectra of PSs were successfully elucidated with the help of MS³/MS⁴ measurements, unveiling complex fragmentation pathways involving both the steroidal backbone and the side chain and indicating C17 as an additional potential site for positive charge localization.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The findings described in the paper offer a strong basis for identifying critical structural features of PSs, thus opening interesting perspectives for the identification of minor PSs, often isomeric with more common ones, that can be detected in vegetal matrices.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 13","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784304","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}