Rapid Communications in Mass Spectrometry最新文献

{"title":"Near-Threshold Photodetachment of WF5− Molecular Anions in a Cryogenic Storage Ring","authors":"Martin Martschini,&nbsp;David Leimbach,&nbsp;Hubert Gnaser,&nbsp;Dag Hanstorp,&nbsp;Mingchao Ji,&nbsp;Paul Martini,&nbsp;Ansgar Simonsson,&nbsp;Rachel Poulose,&nbsp;Mikael Björkhage,&nbsp;Henning Zettergren,&nbsp;Henning T. Schmidt,&nbsp;Robin Golser","doi":"10.1002/rcm.70183","DOIUrl":"10.1002/rcm.70183","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The molecular anion WF₅⁻ constitutes an isobaric interference for the mass spectrometric detection of the HfF₅⁻ anion. The latter is expected to form an extremely sensitive way of detecting the <i>radionuclide</i> ¹⁸²Hf at <i>natural</i> levels using, for example, accelerator mass spectrometry.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Photoinduced detachment of WF₅⁻ molecular anions was studied in the Double ElectroStatic Ion Ring ExpEriment (DESIREE), with the ring cooled to cryogenic temperatures (~13 K). Photon energies from 2.5 to 4.5 eV were applied using an OPO laser system for excitation. This energy range covers the threshold for the removal of an electron from that anion species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Photoinduced reactions were observed which indicate the existence of an energy threshold for WF₅⁻ anions above which the neutralization yield increases strongly. In that range, the data of the neutral signal could be fitted by a linear function of photon energy <i>E</i>, yielding a threshold energy <i>E</i>_th = 3.13 ± 0.01 eV. This result constitutes a substantial improvement both in the range and the resolution of the photon energy as compared to previous data and provides now a rather precise value for that threshold.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This knowledge is required for any attempts to suppress WF₅⁻ anions by photodetachment in the ultrasensitive detection of the very rare <i>radioisotope</i> ¹⁸²Hf using the ¹⁸²HfF₅⁻ analyte anion; for that, the ¹⁸²WF₅⁻ anion would be a stable isobaric mass interference for analyses by accelerator mass spectrometry. The radionuclide ¹⁸²Hf is considered of great interest in various astrophysical environments such as nucleosynthetic processes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149029434","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":"Formula-Level Turnover and Homologous-Series Patterns in Dissolved Organic Matter Associated With Sunlight-Exposed PLA, PET, PE, and PBAT by Negative-Ion ESI FT-ICR Mass Spectrometry","authors":"Jun Dong,&nbsp;Qingzhai Meng,&nbsp;Ruipeng Zhang,&nbsp;Chao Ma,&nbsp;Yulin Qi","doi":"10.1002/rcm.70189","DOIUrl":"10.1002/rcm.70189","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Sunlight exposure can alter plastic-associated material and generate a filterable dissolved organic matter (DOM) pool containing polymer fragments, oxygenated products, and additives. This study compared the molecular composition and time-dependent spectral differences of DOM associated with four widely used plastics.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Particles of poly(lactic acid) (PLA), poly(ethylene terephthalate) (PET), polyethylene (PE), and poly(butylene adipate-co-terephthalate) (PBAT) were dispersed in water and exposed to natural sunlight for 6 or 48 h. After particle removal, DOM was enriched by PPL solid-phase extraction and analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Assigned formulas were compared using elemental classes, intensity-weighted descriptors, van Krevelen distributions, Jaccard similarity, Bray–Curtis dissimilarity, and homologous-series screening.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Between 2247 and 4661 molecular formulas were assigned per sample, with maximum absolute mass errors below 0.60 ppm. Relative to corresponding 6-h spectra, formula numbers were lower at 48 h for PLA (−37.5%) and PET (−39.3%) but higher for PE (+41.8%) and PBAT (+14.0%). Formula-set similarity was lowest for PET (Jaccard 0.329; Bray–Curtis 0.787) and highest for PBAT (0.712; 0.260). In PLA, a C₃H₄O₂-spaced oxygen-rich series increased from 13.4% to 20.9% of the assigned intensity. A C₁₀H₈O₄-spaced PET-related series contributed 8.70% at 6 h and 0.17% at 48 h. PET-48 h was dominated by CHSO formulas, whereas PE showed greater CHNO abundance and higher relative contribution of lower mass oxygenated CH₂ series. PBAT retained the greatest formula-set overlap between spectra.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The 6- and 48-h spectra showed distinct polymer-dependent compositional differences. Homologous-series analysis provided information beyond van Krevelen statistics, whereas nonexclusive N- and S-containing signals highlighted the need for process blanks, dark controls, and tandem mass spectrometry before source-specific assignments. Because replicate and matched control spectra were not available in the analyzed dataset, these differences are interpreted descriptively and do not demonstrate chemical formation, disappearance, or sunlight-specific transformation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149029274","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":"LC–HRMS/MS Characterization of Hydrolytic and Photolytic Degradation Pathways of Ripretinib Following Forced Stress Studies","authors":"Vijaya Madhyanapu Golla,&nbsp;Pushpa Pilli,&nbsp;Bhoopendra Singh Kushwah,&nbsp;Sowmya Chaganti,&nbsp;Rahul Khemchandani,&nbsp;Gananadhamu Samanthula","doi":"10.1002/rcm.70180","DOIUrl":"10.1002/rcm.70180","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Introduction&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Ripretinib is an innovative multitargeted kinase inhibitor introduced for the treatment of advanced gastrointestinal stromal tumors, was investigated to elucidate its degradation behavior and structural transformation pathways under forced stress conditions. Although degradation studies are essential for evaluating the intrinsic stability of pharmaceutical compounds, the degradation products of ripretinib have not been comprehensively characterized. The present work focuses on LC–HRMS/MS-based structural elucidation of degradation products arising from photolytic and hydrolytic stress conditions.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;In accordance with International Council for Harmonisation guidelines, ripretinib was subjected to acidic, alkaline, oxidative, thermal, and photolytic stress conditions. Liquid chromatography was employed to separate the degradation products, which were subsequently characterized by high-resolution tandem mass spectrometry (LC–HRMS/MS) operated in positive electrospray ionization mode. Structural assignments were established using accurate mass measurements, isotopic pattern analysis, elemental composition determination, and collision-induced dissociation pathways. Degradation kinetics under photolytic conditions were also evaluated. An &lt;i&gt;in silico&lt;/i&gt; toxicity assessment of degradation products was performed using DEREK and SARAH prediction platforms.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Ripretinib exhibited degradation predominantly under photolytic and hydrolytic stress conditions, leading to the formation of five degradation products. The protonated molecule of ripretinib at &lt;i&gt;m/z&lt;/i&gt; 510 displayed a characteristic bromine isotopic distribution that facilitated differentiation between brominated and debrominated products. Hydrolytic degradation generated two products through cleavage of the urea linkage, whereas photolytic degradation produced three products involving intramolecular cyclization with concomitant debromination, hydroxylation, and N–C bond cleavage pathways. Collision-induced dissociation of protonated molecules generated diagnostic product ions that enabled structural elucidation of all degradation products. Photodegradation followed apparent first-order kinetics with a half-life of 4.2 min. One hydrolytic degradation product containing a primary aromatic amine moiety was predicted to possess mutagenic potential.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusion&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;This investigation elucidates the degradation pathways of ripretinib and highlights the utility of LC–HRMS/MS in the structural characterization of degradation pro","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015102","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":"Preparation of Deuterium-Labeled Tadalafil and Omeprazole by Carbon Hydrogen–Deuterium Exchange: Hydrogen Scrambling, Acid-Induced Transformation, and LC-MS Applications","authors":"Martyna Hofman-Kotyla,&nbsp;Paulina Grocholska-Zamiara,&nbsp;Robert Wieczorek,&nbsp;Remigiusz Bąchor","doi":"10.1002/rcm.70188","DOIUrl":"10.1002/rcm.70188","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Rationale&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Stable isotope-labeled compounds are indispensable internal standards for reliable liquid chromatography–mass spectrometry (LC-MS) analysis, but their preparation frequently requires multistep synthesis. Base-catalyzed hydrogen–deuterium exchange at carbon centers provides a simple alternative for generating stable isotopologues. Beyond quantitative applications, carbon-bound deuterium may serve as a mechanistic probe for investigating gas-phase fragmentation and chemically induced molecular transformations. In this work, tadalafil and omeprazole were selected as complementary model compounds to evaluate both the analytical applicability of deuterium-labeled standards and the behavior of carbon-bound deuterium during tandem mass spectrometry and acid-induced transformation.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Deuterium-labeled tadalafil and omeprazole were prepared by base-catalyzed hydrogen–deuterium exchange under optimized reaction conditions. The obtained isotopologue mixtures were characterized using high-resolution ESI-MS, multistage tandem mass spectrometry, &lt;sup&gt;1&lt;/sup&gt;H NMR spectroscopy, and density functional theory (DFT) calculations. Their chromatographic behavior, short-term isotope stability, and proof-of-concept applicability as LC-MS internal standards were evaluated using chromatographic comparison and analysis of post-dose human urine samples.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Base-catalyzed hydrogen–deuterium exchange produced isotopologue mixtures dominated by tadalafil-d&lt;sub&gt;3&lt;/sub&gt; and omeprazole-d&lt;sub&gt;2&lt;/sub&gt;. High-resolution mass spectrometry and &lt;sup&gt;1&lt;/sup&gt;H NMR spectroscopy consistently identified selective incorporation of carbon-bound deuterium, whereas DFT calculations explained the observed regioselectivity of the exchange. Tandem mass spectrometry of deuterated tadalafil revealed product-ion mass shifts consistent with hydrogen scrambling, demonstrating migration of carbon-bound deuterium during collision-induced dissociation and providing additional insight into the dissociation mechanism. In contrast, deuterium-labeled omeprazole retained its isotope label during acid-induced transformation. Both labeled compounds exhibited chromatographic behavior suitable for proof-of-concept LC-MS applications.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusions&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Base-catalyzed carbon hydrogen–deuterium exchange provides a rapid and cost-effective approach for preparing stable isotope-labeled tadalafil and omeprazole suitable for LC-MS applications. The study further demonstrates that carbon-bound deuterium constitutes a valuable mechanistic probe, enabl","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149015069","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":"Implementation of Nano Flow Chromatography Coupled to Mass Spectrometry as a Reliable and Sensitive Discovery Lipidomics Platform","authors":"Ciara J. Sallowicz,&nbsp;Thiago Mattos,&nbsp;Rahul R. Deshpande,&nbsp;Bashar Amer,&nbsp;Susan S. Bird","doi":"10.1002/rcm.70175","DOIUrl":"10.1002/rcm.70175","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Untargeted lipidomics is commonly performed at analytical flow rates, which consume more solvent and may require higher on-column sample loads when sensitivity is limited by analyte abundance. Nano flow separations use lower flow rates and sample loads, reducing solvent consumption and facilitating improved electrospray ionization. We present here practical considerations for implementing a routine nano flow lipidomics workflow.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Bovine liver total lipid extract was spiked with SPLASH Lipidomix internal standards and analyzed by nano flow and high flow liquid chromatography coupled to a high-resolution accurate mass Orbitrap-based mass spectrometer. Full-scan polarity switching was used for untargeted profiling, and the AcquireX Deep Scan workflow was applied to support data-dependent MS/MS acquisition in the complex matrix. A SPLASH dilution series was analyzed in triplicate injections to compare analytical response across on-column loads between the two workflows.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>At 25 ng on-column, nano flow yielded 1266 total lipid annotations and 835 high-quality annotations, compared with 919 total and 518 high-quality annotations for high flow at 100 ng. Unintentional fragmentation decreased under nano flow conditions by 21%–31% across the representative lipid species evaluated. The use of nano flow allowed for the detection of lower on-column loads across several standards, extending the lower end of the response range by up to 40-fold compared with high flow analyses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Nano flow lipidomics improved sensitivity for untargeted analysis by increasing the number of lipid annotations, reducing unintentional fragmentation, and extending the analytical response to lower on-column loads. Together with practical guidance around sample preparation, injection volume, washing, and equilibration, these results support nano flow chromatography as a sensitive and reliable approach for sample-limited untargeted lipidomics.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70175","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148987377","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-Precision Rb Isotope Analysis by MC-ICP-MS Using Sr Empirical External Normalization","authors":"Haoming Yin,&nbsp;Qi Feng,&nbsp;Tao Li","doi":"10.1002/rcm.70185","DOIUrl":"https://doi.org/10.1002/rcm.70185","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Stable rubidium (Rb) isotopes have received increasing attention as emerging geochemical tracers for investigating planetary evolution, water–silicate interactions, and global Rb cycling. High-precision Rb isotope measurements by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) are commonly performed using the standard-sample bracketing (SSB) method, but this approach is sensitive to short-term instrumental drift.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Building upon the previously reported empirical external normalization (EEN) with ⁹²Zr/⁹⁰Zr combined with the SSB method, we adopted ⁸⁸Sr/⁸⁶Sr for EEN + SSB MC-ICP-MS Rb isotope measurement, owing to the closer mass discrimination between Sr and Rb. In this study, we correted the isobaric interference of ⁸⁷Sr on ⁸⁷Rb using an exponential law, compared Sr-EEN with Zr-EEN using the in-house USTC-Rb standard, and evaluated elemental doping effects (K, Ca, Na, and Mn).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The results show that the USTC-Rb standard yielded δ^87/85Rb values of −0.15‰ ± 0.04‰ (2SD, <i>n</i> = 33) by Sr-EEN and −0.16‰ ± 0.04‰ (2SD, <i>n</i> = 33) by Zr-EEN, indistinguishable within analytical uncertainty. Elemental doping experiments suggest that the measured Rb isotope data were not significantly affected when the K/Rb, Ca/Rb, Na/Rb, and Mn/Rb ratios were up to 100. The long-term intermediate reproducibility for NIST SRM 984 was 0.00‰ ± 0.04‰ (2SD, <i>n</i> = 121).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Because Sr can be effectively separated from Rb using Sr-spec resin, this Sr-EEN method provides a precise and reliable alternative for Rb isotope determination by MC-ICP-MS and exhibits high tolerance to matrix elements.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148994446","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":"High–Temperature Mass Spectrometric Studies of Ni–V–O System: Thermodynamic Properties Over <Ni3V2O8(s) + NiO(s)> Biphasic Region","authors":"Pooja,&nbsp;V. Venkata Trinadh,&nbsp;C. V. S. Brahmananda Rao","doi":"10.1002/rcm.70181","DOIUrl":"10.1002/rcm.70181","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The Ni–V–O system is of considerable importance owing to its applications in catalysis and electrochemical devices. But experimental thermodynamic data for the Ni–V–O system remain limited. The KEMS study can provide the fundamental thermodynamic data like equilibrium partial pressure of gaseous species over the condensed phase, which can be used to evaluate the thermodynamic functions for the chemical equilibria and the involved condensed phases. The thermodynamic data can be valuable for both practical applications of Ni–V–O systems and fundamental science.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Method/Approach</h3>\u0000 \u0000 <p>High–Temperature Knudsen Effusion Mass Spectrometry (HT-KEMS) was employed to investigate the vaporization behaviour of the Ni–V–O system. Equilibrium partial pressures of the vaporizing species were measured using electron impact ionization mass spectrometry, and the obtained data were utilized for thermodynamic evaluation of the &lt;Ni₃V₂O₈(s) + NiO(s)&gt; biphasic region in the Ni–V–O system.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results/Key Points</h3>\u0000 \u0000 <p>The major vapor species detected over the sample were O₂(g), Ni(g), and VO₂(g). In addition, two minor species were also detected: V(g) and NiO(g). The pressure–temperature (p–T) relations for the major species over &lt;Ni₃V₂O₈(s) + NiO(s)&gt; region were deduced in the experimental temperature range of 1476–1581 K. From the p–T and equilibrium constant–temperature (K–T) relations, based on the second and third law methods of thermodynamics, the enthalpy changes and temperature dependence of Gibbs energy of four reactions were evaluated. Subsequently, the enthalpy of formation at 298 K and Gibbs energy of formation of Ni₃V₂O₈(s) as a function of temperature were deduced.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Thermodynamic properties of the ternary compound Ni₃V₂O₈(s) were deduced employing HT-KEMS measurements.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148981725","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 Serine Octamer Substitution Reactions","authors":"Brison A. Shira,&nbsp;Alana K. E. Thomas,&nbsp;R. Graham Cooks","doi":"10.1002/rcm.70182","DOIUrl":"10.1002/rcm.70182","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Rationale&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Monomeric amino acids substitute into the ionized serine octamer (Ser&lt;sub&gt;8&lt;/sub&gt;), a magic number cluster that exhibits chiral behavior. Small biomolecules, such as amino acids (AA), substitute into the octamer enantioselectively, giving Ser&lt;sub&gt;7&lt;/sub&gt;AAH&lt;sup&gt;+&lt;/sup&gt; and Ser&lt;sub&gt;6&lt;/sub&gt;AA&lt;sub&gt;2&lt;/sub&gt;H&lt;sup&gt;+&lt;/sup&gt; favoring clusters of all L- or all D-chirality. While the formation of Ser&lt;sub&gt;8&lt;/sub&gt;H&lt;sup&gt;+&lt;/sup&gt; has been well studied, its substitution reactions need further investigation. The fact that water microdroplets readily produce Ser&lt;sub&gt;8&lt;/sub&gt;H&lt;sup&gt;+&lt;/sup&gt;, which undergoes enantiospecific substitution reactions perhaps gives this topic relevance to origins of life chemistry.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The substitution reactions of several proteogenic AA's (Ala, Leu, isoLeu, Pro, Phe, and Val), along with prebiotically relevant isomers (norVal and isoVal), were investigated using a quadrupole ion trap mass spectrometer to gain insight into the determinants of the chiral behavior. Rather than using isotopically labeled enantiomers, as in previous work, cluster formation was assessed using samples of variable chiral composition and concentration.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Substitution enantioselectivity was confirmed, though in the case of some double substitutions and the substitution of nonproteogenic isomers, the homochiral preference was decreased or inverted, an observation which is attributed to the disruption of the highly ordered noncovalent contacts of the parent Ser&lt;sub&gt;8&lt;/sub&gt; cluster. Additionally, the data suggest that octamer formation is consecutive: Ser&lt;sub&gt;8&lt;/sub&gt;H&lt;sup&gt;+&lt;/sup&gt; forms first, followed by substitution of AA to form Ser&lt;sub&gt;7&lt;/sub&gt;AAH&lt;sup&gt;+&lt;/sup&gt;, sometimes followed by a second substitution to form Ser&lt;sub&gt;6&lt;/sub&gt;AA&lt;sub&gt;2&lt;/sub&gt;H&lt;sup&gt;+&lt;/sup&gt;.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusions&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;This investigation illustrates how chiral chemistry using MS must operate through weak but chirality-sensitive forces while avoiding dominance of stronger but chirality-insensitive reaction drivers; namely the propensity of a chiral organic base to acquire the charge of a proton affiliated with other chiral molecules. These results are significant because chiral molecular clusters are fundamentally interesting. Understanding the origins of their enantioselectivity contributes to a general understanding of how small molecules may recognize chirality in reaction partners and accumulate enantiomeric excess.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 &lt;/d","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70182","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148981882","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":"Detection and Excretion Profile of Retatrutide in Human Plasma and Urine by LC-HRMS: Implications for Antidoping Analysis","authors":"Gabriel Reis Alves Carneiro,&nbsp;Isabelle Karine da Costa Nunes,&nbsp;Gustavo Ramalho dos Santos Cardoso,&nbsp;Paola Façanha dos Santos,&nbsp;Monica Costa Padilha,&nbsp;Fábio César Sousa Nogueira,&nbsp;Henrique Marcelo Gualberto Pereira","doi":"10.1002/rcm.70179","DOIUrl":"https://doi.org/10.1002/rcm.70179","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Retatrutide (LY3437943) is a novel long-acting triple incretin receptor agonist that targets the glucagon-like peptide-1 receptor (GLP-1R), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon receptor (GCGR). Its pronounced effects on body composition and metabolic health, combined with increasing off-label use among physically active populations, raise concerns about potential misuse in sport. Despite growing clinical interest and anecdotal reports about use among amateur athletes, information on the detection and elimination profile of retatrutide in humans remains unexplored.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A method based on liquid chromatography–high-resolution mass spectrometry (LC-HRMS) dedicated to monitor retatrutide was developed and validated in human plasma and urine in accordance with World Anti-Doping Agency (WADA) criteria. Detection was based on the [M + 3H]³⁺ precursor ion by targeted selected-ion monitoring (t-SIM), with confirmatory analysis via parallel reaction monitoring (PRM) of structurally diagnostic fragment ions. From four retatrutide users who self-administered 2 mg subcutaneously on Days 1 and 7, blood and urine samples were collected at predefined time points following self-administration.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The method was proved fit-for-purpose regarding selectivity, reliability, robustness, and stability. Limits of detection (LOD) were evaluated using both empirical ≥ 95% detection rate criteria and sigmoidal logistic regression modeling, yielding 6.14 ng/mL in plasma and 2.44 ng/mL in urine. Neither intact retatrutide nor metabolite-derived signals were detected in urine samples throughout the entire collection period, despite systematic application of multiple extraction strategies. Plasma concentration–time profiles exhibited nonmonotonic behavior, consistent with prolonged subcutaneous absorption and depot-like release kinetics following repeated dosing.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>These findings suggest that plasma represents the appropriate matrix for intact retatrutide detection compared with urine. The extended plasma detection window, approximately 56 days after the first dose, supports plasma-based testing as a suitable analytical strategy for this and related long-acting therapeutic peptides in antidoping testing context.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148965632","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":"Stable Isotope Analysis (δ13C, δ15N and δ18O) of Killer Whale Dentine: Evaluating Treatment Methods and Establishing Best Practices","authors":"Maeva Terrapon,&nbsp;Philip S. Hammond,&nbsp;Rona A. R. McGill,&nbsp;Jason Newton,&nbsp;Julie Dougans,&nbsp;Cory J. D. Matthews,&nbsp;Sascha K. Hooker","doi":"10.1002/rcm.70176","DOIUrl":"https://doi.org/10.1002/rcm.70176","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Stable isotope measurements in odontocete teeth can be used to reconstruct lifetime ecology, but some pre-treatments may introduce bias. Isolating dentine collagen with HCl decalcification, removing the organic matrix or drying dentine prior to the analysis of structural carbonates can introduce unintended variability, limiting comparability among studies and populations. This study tested pre-treatment methods to quantify their effects.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Killer whale teeth were sectioned, annual growth layers microdrilled, and powder allocated to treatments. For collagen δ¹³C and δ¹⁵N, 75 samples were analysed via EA-IRMS as untreated bulk dentine and after 0.25 N HCl decalcification. For structural carbonate δ¹³C and δ¹⁸O, treatment with 30% H₂O₂ was compared with plasma-ashing and with no treatment (<i>n</i> = 16); and we examined the removal of residual water by comparing samples oven-dried at 80°C or 100°C with untreated samples (<i>n</i> = 10). All samples for carbonate analysis were injected with 104% orthophosphoric acid to generate CO₂, which was analysed using continuous-flow IRMS.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>HCl decalcification caused mass loss (96.6% ± 2.0%) but yielded collagen of an acceptable quality (C:<i>N</i> = 3.3 ± 0.2). Compared with untreated dentine, collagen δ¹³C decreased (Δmedian = −0.34‰) while δ¹⁵N did not differ significantly. Organic-matrix removal treatments altered both isotopes: plasma-ashed samples showed large negative shifts compared with untreated samples in δ¹³C (Δmedian = −9.04‰) and δ¹⁸O (Δmean = −13.48‰) and reduced measurable carbon. H₂O₂ treatments lowered δ¹³C relative to untreated samples (Δmean = −0.93‰) but showed no consistent δ¹⁸O effect. Drying at 80°C minimised δ¹³C and δ¹⁸O variability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>HCl decalcification is recommended before δ¹³C and δ¹⁵N collagen analysis of killer whale dentine, or a δ¹³C correction factor (here −0.34‰) should be applied. Treatments were unsuitable when undertaking structural carbonate analyses of hydroxyapatite: we suggest that untreated powder oven-dried overnight at 80°C should be used, and we emphasise the importance of pre-treatment tests prior to any new study.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70176","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148965622","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}