Rapid Communications in Mass Spectrometry最新文献

{"title":"High temperature mass spectrometric studies over Zr-Al binary system: Thermodynamic properties over <ZrAl3(cr) + ZrAl2(cr) > and <ZrAl2(cr) + Zr2Al3(cr) > biphasic regions","authors":"Vinjavarapu Venkata Trinadh,&nbsp;Suranjan Bera,&nbsp;Cherukuri Venkata Siva Brahmananda Rao","doi":"10.1002/rcm.9914","DOIUrl":"https://doi.org/10.1002/rcm.9914","url":null,"abstract":"<p>Vaporisation thermodynamic studies were performed over &lt;ZrAl₃(cr) + ZrAl₂(cr) &gt; and &lt;ZrAl₂(cr) + Zr₂Al₃(cr) &gt; biphasic region of Al-Zr system by employing Knudsen Effusion Mass Spectrometry (KEMS) in the temperature range between 1,233 to 1,535 and 1,208 to 1,458 K, respectively. It was observed that these samples undergo incongruent vaporisation with Al(g) alone in the vapour phase. Following are the recommended p–T relations deduced in the present study:</p><p>log (p_Al/Pa) = (−18,663 ± 132)/T + (12.23 ± 0.10) (1,233–1,535 K) &lt; ZrAl₃(cr) + ZrAl₂(cr)&gt;.</p><p>log (p_Al/Pa) = (−18,982 ± 112)/T + (11.92 ± 0.08) (1,208–1,458 K) &lt; ZrAl₂(cr) + Zr₂Al₃(cr)&gt;.</p><p>From the p–T and K-T relations, based on the second and third law methods of thermodynamics, the enthalpy changes of the following reactions were evaluated: ZrAl₃(cr) = ZrAl₂(cr) + Al(g) and 2ZrAl₂(cr) = Zr₂Al₃(cr) + Al(g). Subsequently, the enthalpies of the formation of ZrAl₂(cr) and Zr₂Al₃(cr) were deduced.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9914","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276577","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":"Equine metabolic investigation of the phosphodiesterase-4 inhibitor ibudilast as a potential performance enhancer","authors":"Moses Philip,&nbsp;Abdul Khader Karakka Kal,&nbsp;Michael Benedict Subhahar,&nbsp;Tajudheen K. Karatt,&nbsp;Fatma Mohammed Graiban,&nbsp;Meleparappil Muhammed Ajeebsanu,&nbsp;Marina Joseph,&nbsp;Shantymol V. Jose","doi":"10.1002/rcm.9916","DOIUrl":"10.1002/rcm.9916","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Phosphodiesterase 4 (PDE4) inhibitors are a newer class of drugs that induce bronchodilation and have anti-inflammatory effects, making them susceptible to misuse as performance enhancers in competitive sports.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study explores the metabolic conversion of PDE4 inhibitor ibudilast in thoroughbred horses after oral administration and in vitro using equine liver microsomes and <i>Cunninghamella elegans</i>. A liquid chromatography-high resolution mass spectrometry method was used to postulate the plausible structures of the detected metabolites.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>A total of 20 in vivo metabolites were identified under experimental conditions, including 12 Phase I and 8 Phase II conjugated metabolites. Phase I metabolites were predominantly formed through hydroxylation (mono-, di-, and tri-hydroxylation). Demethylated metabolites were also identified during this investigation. Additionally, the research detected Phase II metabolites conjugated with glucuronic and sulfonic acids.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The data presented here can assist in detecting the PDE4 inhibitor ibudilast and uncover its illicit use in competitive sports.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142277695","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":"An optimised method to isotopically label pure synthetic peptides ‘in-house’ for absolute quantification in bottom-up proteomics","authors":"Nikita Bhakta,&nbsp;Colleen B. Maxwell,&nbsp;Shimon Atunde,&nbsp;Jatinderpal K. Sandhu,&nbsp;Oliver C. Slingsby,&nbsp;Emer M. Brady,&nbsp;Donald J. L. Jones,&nbsp;Leong L. Ng","doi":"10.1002/rcm.9892","DOIUrl":"https://doi.org/10.1002/rcm.9892","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Heavy-labelled internal standards increasingly represent the gold standard for absolute quantitation in mass spectrometry (MS)-based bottom-up proteomics. The biggest drawbacks of using these standards are that they have high costs and lengthy lead times.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We describe an efficient, low-cost optimised method to enable ‘in-house’ heavy labelling of synthetic tryptic peptides for absolute quantification using tandem LC-MS/MS mass spectrometry. Our methodology uses 18O water in a trypsin-catalysed oxygen exchange reaction at the carboxyl terminus with the overall aim of reducing the costs and lead time associated with sourcing heavy standards from commercial vendors.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Step-by-step instructions are provided on how to execute this protocol with high-throughput adaptations utilising a 96-well plate and a liquid-handling robot. Detailed notes on experimental setup, tips for troubleshooting and suggested improvements to maximise labelling efficiencies are highlighted to achieve the best results. Under optimum conditions, labelling efficiencies of peptides can reach from 95% to 100%.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The application of the ‘in-house’ labelled standards in generating calibration curves to quantify endogenous peptide concentrations is just as effective as using the synthetically sourced standards while also having great cost reduction implications as well as saving time spent waiting for peptides to arrive. The protocol is highly adaptable and can be customized to fit the specific setup of any laboratory, maximizing achievable labelling efficiencies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 22","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9892","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245001","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":"Reference-free thio-succinimide isomerization characterization by electron-activated dissociation","authors":"Junyan Yang,&nbsp;Jiaqi Yuan,&nbsp;Yue Huang,&nbsp;Anton I. Rosenbaum","doi":"10.1002/rcm.9910","DOIUrl":"https://doi.org/10.1002/rcm.9910","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Isomerism can be an important aspect in pharmaceutical drug development. Identification of isomers can provide insights into drug pharmacology and contribute to better design of drug molecules. The general approaches to differentiate isomers include Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and circular dichroism. Additionally, a commonly used method to differentiate isomers is liquid chromatography coupled with mass spectrometry (LC-MS). Notably, LC-MS is routinely applied to leucine and isoleucine differentiation to facilitate protein sequencing. This work focuses on isomer differentiation of widely employed thio-succinimide structure bridging the antibody backbone and linker-payload of antibody-drug conjugates (ADCs). Thio-succinimide hydrolysis stabilizes the payload-protein structure while generating a pair of constitutional isomers: thio-aspartyl and thio-isoaspartyl.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This paper introduces a hybrid method using ligand binding assay (LBA) and liquid chromatography coupled with tandem MS (LC–MS/MS) to reveal isomerization details of thio-succinimide hydrolysis over time in plasma samples incubated with ADC. Application of two orthogonal dissociation methods, collision-induced dissociation (CID) and electron-activated dissociation (EAD) revealed different MS/MS spectra for this pair of isomers. This observation enables a unique approach in distinguishing thio-succinimide hydrolysis isomers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We observed signature [R₁ + Thio + 57 + H]⁺, [R₂ + Succ + H₂O − 57 + H]⁺, and [R₂ + Succ + H₂O − 44 + 2H]²⁺ product ions (Succ = succinimide) that differentiated thio-aspartyl and thio-isoaspartyl isomers using EAD. A newly discovered [R₂ + ThioSucc + H₂O − 44 + 2H]²⁺ ion also served as additional evidence that further supported our findings.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study is a first-to-date identification of thio-succinimide hydrolysis isomers without using synthesized reference materials. This approach should be applicable to all thio-succinimide-linked molecules. Correct identification of thio-succinimide hydrolysis isomers may eventually benefit the development of ADCs in the future.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9910","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245002","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":"Utilizing ESI-MS/MS and ion mobility spectrometry for structural characterization and isomer differentiation of 1, 2-unsaturated (1-4) linked disaccharide derivatives and their 2-C-functionalized analogues","authors":"Ines Starke,&nbsp;Sylvia Fürstenberg,&nbsp;Steffen Thomas","doi":"10.1002/rcm.9899","DOIUrl":"https://doi.org/10.1002/rcm.9899","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The 1, 2-unsaturated derivatives of (1-4) linked disaccharides serve as versatile building blocks for synthesizing biologically active compounds. Distinguishing between four pairs of stereoisomers in mixtures presents a challenging task. In this study, disaccharide derivatives are analyzed as alkali metal adducts using electrospray ionization tandem mass spectrometry (ESI-MS/MS), both as individual compounds and in mixtures by ion mobility mass spectrometry (IMS).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Electrospray ionization (ESI) in combination with tandem mass spectrometry (MS/MS) in positive mode was employed to differentiate lithium adduct ions of hexa-acetyl/hexa-benzyl-D-lactals, and hexa-acetyl/hexa-benzyl-D-maltals, along with their corresponding 2-<i>C</i>-branched malonates. The high resolving power of trapped ion mobility spectrometry (TIMS) with the imeX™ functionality rapidly identified different metal adducts (Li, Na, Cs) as individual isomers and separated mixtures of stereoisomers. The measured collisional cross section (CCS) values were analyzed in relation to predicted CCS values.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>MS/MS spectra of the [M + Li]⁺ ions of glycal disaccharide analogues exhibited typical cross-ring and glycosidic bond cleavages. Collision-induced dissociation (CID) spectra provided insights into their fragmentation behavior, allowing differentiation of (1-4) linked disaccharides. TIMS technology delivered adjustable ion mobility resolution for suitable separation of the four sets of stereo isomeric compounds. However, accurately predicting CCS values to differentiate between respective isomeric pairs using the <i>Sigma</i>CCS program for sodium adducts is only partially achievable.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>ESI CID spectra of [M + Li]⁺ adduct ions for individual glycal disaccharide analogues facilitate the discrimination between alpha and beta (1-4) linked unsaturated disaccharides and their 2-<i>C</i>-branched analogues. Through optimized experimental conditions, complete baseline ion mobility separation of stereoisomer pairs of the Cs adducts is achieved.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9899","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142174310","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":"Complete resolution across the neodymium/samarium isotopic envelope with a liquid sampling-atmospheric pressure glow discharge — Orbitrap mass spectrometer","authors":"Joseph V. Goodwin,&nbsp;Suraj Shrestha,&nbsp;Benjamin T. Manard,&nbsp;R. Kenneth Marcus","doi":"10.1002/rcm.9912","DOIUrl":"https://doi.org/10.1002/rcm.9912","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Nd and Sm isotope ratios play an important role in geological dating and as nuclear forensic signatures; however, the overlap of the respective 144, 148, 150 Nd/Sm isobars requires prior separations to be performed before analysis on typical MS platforms. The work presented here overcomes these isobaric interferences using ultrahigh-mass resolution to alleviate interference without prior chemical separations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A liquid sampling-atmospheric pressure glow discharge ion source was coupled to a standard, QExactive Focus Orbitrap mass spectrometer, providing a mass resolution of ~80 k. A Spectroswiss FTMS booster X2 data acquisition package was used to collect extended transients, providing much higher mass resolution; ~230 k and ~600 k are employed here for Nd and Sm isotopes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>While the standard Orbitrap resolution is far greater than typical “atomic” MS platforms, it was insufficient to alleviate all isobars. The use of a resolution of ~230 k resulted in baseline separation across the entire isotopic envelope for both Nd and Sm. Isotope ratios obtained from Nd:Sm mixtures using high-resolution were equivalent to those found for individual-element solutions, while isotope ratios obtained at a resolution of ~80 k (standard for the OEM data system) showed large deviations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Use of ultrahigh-resolution is an attractive alternative to extensive chemical separations to alleviate severe isobaric interferences. Sufficient mass resolution greatly reduces/eliminates the need for sample manipulations (separations) before analysis while reducing costs and total analysis times.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9912","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142174091","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":"Multireflecting gas chromatography-multireflecting time-of-flight mass spectrometer with high dynamic range","authors":"Aleksey V. Vorobyev,&nbsp;Yury I. Khasin,&nbsp;Vasily V. Makarov,&nbsp;Sergey N. Kirillov,&nbsp;Anatoly N. Verenchikov","doi":"10.1002/rcm.9909","DOIUrl":"https://doi.org/10.1002/rcm.9909","url":null,"abstract":"<p>Gas chromatography–mass spectrometry (GC–MS) is a cornerstone technique for analyses of volatile and semivolatile compounds, constantly evolving to meet new challenges. The adoption of time-of-flight mass spectrometers (TOFMS) has enhanced GC–MS with faster spectral acquisition and broader mass coverage, enabling rapid GC separations. Multireflecting TOFMS (MRT) further improves resolution compared to traditional single-reflecting TOFMS, facilitating the detection of minor analytes within complex matrices. This paper presents a significant improvement in MRT sensitivity and dynamic range achieved through an ion beam compression within the ion guide and the use of a conventionally oriented orthogonal accelerator. Sensitivity is improved to 100 000 ion/pg at a resolution of <i>R</i> = 25,000, enabling the detection of low fg analyte quantities within 3 μg of matrix material into MS. The demonstrated linear dynamic range exceeding 6 orders of magnitude potentially enables even deeper exploration of complex mixtures with a bench top instrument.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 23","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142165719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of an UPLC-MS/MS approach to detect and quantify N-nitroso mirabegron in mirabegron","authors":"Ravi Uppala,&nbsp;Rakesh Chandrakant Prabhu,&nbsp;Arthanareeswari Maruthapillai,&nbsp;Bandaru Venkatasubbaiah,&nbsp;Gopal Chandru Senadi,&nbsp;Sundaramurthy Devikala","doi":"10.1002/rcm.9911","DOIUrl":"10.1002/rcm.9911","url":null,"abstract":"<p>In the mirabegron (MIR) synthesis, the N-nitroso mirabegron (NNM) is obtained during synthetic process of MIR; water is being used in reaction under acidic condition. Nitrite source is from water, and secondary amine source is from MIR as it has secondary amine; NNM is generated as an impurity during the synthesis of MIR. The presence of NNM in MIR could potentially affect its effectiveness. The purpose of this study was to establish a Ultra-performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS) methodology to identify NNM in MIR samples. The method for NNM analysis was developed on Acquity HSS T3 (100*2.1) mm 1.8 μm column with gradient elution using mobile phase consisted of 0.1% formic acid in water (mobile phase A) and 0.1% formic acid in methanol (mobile phase B). Mass spectrometer with electrospray ionization operated in the MRM mode was used in the analysis of NNM (m/ z 426.20 → 170.00). The UPLC-MS/MS methodology proposed showed a good linearity (0.02 to 0.72 ppm), good system precision (RSD = 0.57%), good method precision (RSD = 0.87%), acceptable accuracy (94.5–116.5%), low detection limit (0.006 ppm) and low quantification limit (0.02 ppm) for NNM. The UPLC-MS/MS methodology proposed can be utilized to assess the quality of MIR sample for the presence of NNM impurity.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 22","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142138823","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":"Coping with spectral interferences when measuring water stable isotopes of vegetables","authors":"Barbara Herbstritt,&nbsp;Lena Wengeler,&nbsp;Natalie Orlowski","doi":"10.1002/rcm.9907","DOIUrl":"10.1002/rcm.9907","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Laser-based analyzers are widely used in ecohydrology to analyze plant water isotopic compositions (δ¹⁸O and δ²H). The suitability of three different water extraction and isotope equilibration techniques was compared. We examined whether co-extracted volatile organic compounds (VOCs) affect laser-based isotope measurements and used the instrument's spectral parameters to post-correct for interfering VOCs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Cryogenic vacuum extraction, vapor headspace equilibration in bags, and vapor equilibration in situ probes were used to extract liquid water or water vapor for laser-based isotope analysis (cavity ring-down spectrometry, CRDS). Isotope data were calibrated by standards for each method separately. Spectral parameters of the instrument, appropriate to identify spectral interferences with MeOH and CH₄, were identified and used for post-correction. Differences between the three methods and between the origins of the vegetables were identified by statistical tests.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>VOCs were found in various amounts for the three different methods. They were co-extracted or co-equilibrated during the different extraction or equilibration methods. Correlation coefficients of isotope data and “CH₄” (spectral parameter) were 0.99 or better; however, slopes for δ¹⁸O were similar on different instrument types but different for δ²H. Our correction approach improved results and inter-comparability of the methods considerably without knowing the chemical composition of the plant sap.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>All three methods were sensitive enough to distinguish and resolve differences in natural abundance. Data quality was improved by the “CH₄ correction” approach but could probably be optimized by a plant species–specific correction. Standardized tools for contaminant removal or post-correction applications from manufacturers, in particular for vapor-mode analysis, are still needed.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 22","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9907","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142131402","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":"New type of filaments for improved accuracy of multiple sulfur isotope analyses by electron-impact gas-source mass spectrometry","authors":"Pierre Cartigny,&nbsp;Amaury Bouyon,&nbsp;Hartmut Bars,&nbsp;Nina Albrecht,&nbsp;Issaku E. Kohl,&nbsp;Guillaume Landais,&nbsp;Arnaud Duverger,&nbsp;James Farquhar","doi":"10.1002/rcm.9873","DOIUrl":"10.1002/rcm.9873","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The analysis of the three sulfur stable isotope ratios (³³S/³²S, ³⁴S/³²S, ³⁶S/³²S) is routinely performed by gas-source isotope ratio mass spectrometry (IRMS) on the SF₆ gaseous molecule, collecting SF₅⁺ ions at <i>m</i>/<i>z</i> ~ 127, 128, 129 and 131. High precision and accuracy are commonly achieved owing to a lack of correction because fluorine has only one isotope and the inert nature of the SF₆ molecule. The analysis of the ³⁶S/³²S ratio is, however, complicated by the low abundance of ³⁶S (~0.015%) and the possible occurrence of trace amounts of fluorocarbon compounds leading to ¹²C₃F₅⁺ ions at <i>m</i>/<i>z</i> ~ 131, i.e. where ³⁶SF₅⁺ ions are collected.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used gas-source high-resolution IRMS to better characterize the nature of possible interferences, and we tested novel types of filaments in order to investigate their influence on possible interferences.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We confirm that the ¹²C₃F₅⁺ ion represents the main isobaric interference at <i>m</i>/<i>z</i> ~ 131. We also demonstrate that tungsten fluoride adducts are formed from the reaction of fluorine ions derived during fragmentation of the SF₆ molecule with the hot tungsten filament. These reactions lead to the formation of e.g. WF₅⁺, WF₄⁺, WF₃⁺ ions, including doubly charged ions. WF₄⁺⁺, in particular, leads to isobaric interference on <i>m</i>/<i>z</i> ~ 128, 129 and 131 from ¹⁸⁰WF₄⁺⁺, ¹⁸²WF₄⁺⁺ and ¹⁸⁶ WF₄⁺⁺ ions, respectively. Because ¹⁸⁰W (0.12%) is at low abundance, its influence on δ³³S measurements would remain negligible, but ¹⁸²W (26.5%) and ¹⁸⁶W (28.4%) lead to scale contraction for both δ³⁴S and δ³⁶S.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Rather than correcting for these interferences, or working at high mass resolution, we suggest avoiding W isobaric interferences by using other types of filaments, with initial reports on both pure Re filaments and Y₂O₃-coated W filaments.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"38 22","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142131403","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}