Rapid Communications in Mass Spectrometry最新文献

{"title":"Discrimination Factor of Sulphur Stable Isotope Ratios Between Pregnant Fin Whales and Their Foetuses","authors":"Marc Ruiz-Sagalés,&nbsp;Asunción Borrell,&nbsp;Alex Aguilar","doi":"10.1002/rcm.10057","DOIUrl":"https://doi.org/10.1002/rcm.10057","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>In-utero synthesised tissues of mammals have often been used to infer maternal behaviour during gestation. Differences in <i>δ</i>¹⁵N or <i>δ</i>¹³C values between foetal and maternal tissues (foetus–mother discrimination factors) are well established, but they remain uncertain for <i>δ</i>³⁴S values. This study addresses this gap by investigating such discrimination in <i>δ</i>³⁴S values of fin whale muscle (<i>Balaenoptera physalus</i>) and its potential variation throughout gestation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We analysed muscle <i>δ</i>³⁴S values in 11 pregnant fin whales and their respective foetuses. Samples were obtained from individuals feeding off northwestern (NW) Spain during the 1983–1985 summer seasons. Yearday (0–365) and foetal length at the moment of sampling were considered proxies of the gestation stage and their effect on discrimination factors was examined. The <i>δ</i>³⁴S values were determined by continuous flow isotope ratio mass spectrometry.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p><i>δ</i>³⁴S values in foetal and maternal muscle were positively correlated. <i>δ</i>³⁴S values were higher in foetal muscle (M ± SD = 19.2 ± 0.3 ‰) compared to the maternal one (M ± SD = 18.6 ± 0.4 ‰), with a foetus–mother discrimination of Δ³⁴S = 0.59 ± 0.15 ‰. This observed enrichment may be due to differences in isotopic turnover rates, amino acid metabolism, and/or maternal dietary patterns during gestation. The foetus–mother <i>δ</i>³⁴S discrimination values did not change with yearday or foetus length.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These findings are relevant for understanding foetal-maternal <i>δ</i>³⁴S discrimination and drawing ecological inferences from foetal tissues. Further research is needed to understand the mechanisms driving <i>δ</i>³⁴S fractionation under different scenarios.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879944","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":"Precision Chemotherapy: Optimizing Calibration for Rapid Determination of Blood Methotrexate by Tandem Mass Spectrometry ± Liquid Chromatography","authors":"Dennis J. Dietzen,&nbsp;Connor J. Blair","doi":"10.1002/rcm.10053","DOIUrl":"https://doi.org/10.1002/rcm.10053","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Rapid therapeutic monitoring of high-dose methotrexate (MTX) chemotherapy is essential to avoid toxicity. MTX concentrations are commonly monitored using immunoassays that are limited by narrow dynamic range and metabolite cross reactivity. Mass spectrometry may improve the molecular specificity of MTX analysis but is limited by slow throughput and extensive calibration. In this study, we examined the consequences of eliminating LC from MS/MS and foregoing external calibration to enable rapid determination of MTX.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>MTX (m/z 455 → 308), was assessed using UPLC–MS/MS or flow-injection MS/MS using a six-point external calibration scheme with a single deuterated internal standard, 4-point internal calibration using ¹³C₅, ¹³C₆, ¹³C₁₁, and ¹³C₁₄-MTX, or by single point calibration with the single deuterated internal standard. Accuracy, precision, and resistance to hemolysis, icterus, and lipemia were compared with immunoassay.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Across all six injection/calibration schemes, imprecision ranged from 2.5% to 10% (CV) from 0.05–10 μM. Regardless of calibration scheme, MS/MS ± LC was more resistant to interference from hemolysis and bilirubin than immunoassay. MS/MS ± LC determination of MTX was compared with immunoassay in 81–100 plasma specimens with MTX concentrations ranging from 0.05–81 μM. Intercept estimates all included zero with 95% confidence. Estimates of slopes versus immunoassay for each of the six analytic approaches ranged from 0.88 to 1.09.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Eliminating LC and external calibration enabled rapid, precise, and accurate determination of MTX concentrations in plasma. Minimalist but robust approaches such as these may enable the use of MS for routine MTX determination in time-sensitive clinical circumstances.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880117","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":"Examination of Fe and Cu Isotope Variation in Great Apes Using an Optimized Protocol","authors":"Renee D. Boucher,&nbsp;Linda V. Godfrey,&nbsp;Lars Fehren-Schmitz,&nbsp;Paul L. Koch","doi":"10.1002/rcm.10051","DOIUrl":"https://doi.org/10.1002/rcm.10051","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Iron deficiency plagues reproductive-aged women across the world, and blood loss during menstruation is proposed as the driving force. To assess if other factors related to reproduction influence Fe and Cu isotope variation in females, we measured Fe and Cu isotope compositions in the bones of chimpanzees and bonobos.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To do this, we optimize the protocol for isolating Fe and Cu (and Zn) from phosphate-rich skeletal materials for further analysis via MC-ICP-MS. Then, we address possible Fe and Cu variation sources in non-menstruating apes (<i>n</i> = 26, of which the sex of 10 was obtained by DNA analysis).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The optimized method reduced acid volume by ~14%, and sample preparation time by ~37.5%. We did not find significant sex differences in δ⁵⁶Fe values (Δ⁵⁶Fe_f-m = 0.13‰) or δ⁶⁵Cu values (Δ⁶⁵Cu_f-m = 0.33‰).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Given the similar Δ⁵⁶Fe_f-m values between non-menstruating apes and humans, reproductive investment, instead of menstruation alone, is a key factor that drives Fe deficiency in reproductive-aged women and is important to consider with proxies of iron status. Our optimized protocol provides an effective method for exploring iron status in other mammalian species.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865916","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":"Stable Isotope Reference Materials and Scale Definitions—Outcomes of the 2024 IAEA Experts Meeting","authors":"Federica Camin,&nbsp;Dinka Besic,&nbsp;Paul J. Brewer,&nbsp;Colin E. Allison,&nbsp;Tyler B. Coplen,&nbsp;Philip J. H. Dunn,&nbsp;Matthias Gehre,&nbsp;Manfred Gröning,&nbsp;Harro A. J. Meijer,&nbsp;Jean-François Hélie,&nbsp;Paola Iacumin,&nbsp;Rebecca Kraft,&nbsp;Bor Krajnc,&nbsp;Steffen Kümmel,&nbsp;Sangil Lee,&nbsp;Juris Meija,&nbsp;Zoltan Mester,&nbsp;Joachim Mohn,&nbsp;Heiko Moossen,&nbsp;Haiping Qi,&nbsp;Grzegorz Skrzypek,&nbsp;Peter Sperlich,&nbsp;Joelle Viallon,&nbsp;Leonard I. Wassenaar,&nbsp;Robert I. Wielgosz","doi":"10.1002/rcm.10018","DOIUrl":"https://doi.org/10.1002/rcm.10018","url":null,"abstract":"<p>The participants of the 12^th International Atomic Energy Agency (IAEA) meeting on stable isotope reference materials reached a consensus, acknowledging the existence and use of two carbon isotope delta scales: the VPDB (Vienna Peedee belemnite) scale and the VPDB-LSVEC (LSVEC - lithium carbonate prepared by H. J. Svec). Conversion models between the two scales can be established and used but introduce uncertainty. A format for isotope delta scale definition was agreed upon and was used to define the two carbon isotope delta scales and the two main oxygen isotope delta scales, VSMOW-SLAP (Vienna Standard Mean Ocean Water–Standard Light Antarctic Precipitation) and VPDB. Confirmation or identification of a second-scale–defining point is still necessary for the nitrogen and sulfur isotope delta scales.</p><p>Efforts are encouraged to improve consistency among laboratories in the isotopic analysis of “non-exchangeable hydrogen” in bulk organic materials and oxygen in carbonates using the phosphoric acid reaction. Additional topics discussed include (1) need for improvement in reference materials for accurate greenhouse gas isotopic analyses; (2) reference materials under production by the IAEA, the US Geological Survey (USGS), and the US National Institute of Standards and Technology (NIST); (3) methods for value and uncertainty assignment of reference materials; and (4) calculation of carbon-13 isotope delta and oxygen-18 isotope delta of CO₂ measured by dual-inlet isotope ratio mass spectrometry.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"39 14","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.10018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871470","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":"Gas Chromatography–Mass Spectrometry Analysis and Bioactive Potential of Selected Medicinal Plants","authors":"Waheed Khan,&nbsp;Muhammad Saleem Khan,&nbsp;Ghulam Saddiq,&nbsp;Muhammad Zafar,&nbsp;Salman Majeed,&nbsp;Mohamed Fawzy Ramadan,&nbsp;Muhammad Ishtiaq Ali,&nbsp;Nasibakhon Naraliyeva,&nbsp;Trobjon Makhkamov,&nbsp;Zulunov Islom,&nbsp;Aneta A. Ptaszyńska","doi":"10.1002/rcm.10049","DOIUrl":"https://doi.org/10.1002/rcm.10049","url":null,"abstract":"<div>\u0000 \u0000 <p>Plants offer unlimited source of bioactive compounds that have tremendous applications in pharmaceutical industry to find new sources of medicinal plants (MPs) were evaluated. Gas chromatography–mass spectrometry were used to identify the bioactive compounds of selected medicinal plants. Both extracts contained multiple compounds. The most abundant ones were 3,4-dimethyl-1,5-hexadiene-3,4-diol (7.93%), tau-cadinol (5.84%), and adenosine, N6-phenylacetic acid (5.84%) in one extract. In the other extract, the major compounds were 2-methylcumarone (16.92%), 7-methylbenzo[b]furan (14.81%), and (3E,5E)-3,5-octadien-2-one (10.25%). Some of these compounds have antimicrobial, anticancer, and antioxidant properties. Antioxidant tests showed that <i>Solanum nigrum</i> had the highest antioxidant activity (96.59% at 14.4 concentration), followed closely by <i>Artemisia scoparia</i> (96.55% at 13.2 μg/mL), <i>Tribulus longipetalus</i> (94.76% at 13.6 μg/mL), and <i>Mentha longifolia</i>, which had the lowest (81.94% at 18.4 μg/mL), whereas ascorbic acid, the standard, had the highest value (98.34% μg/mL). The antimicrobial properties of four selected MPs were evaluated. The plant <i>T. longipetalus</i> exhibited the highest zones of inhibition (18 and 20.5 mm) against <i>Pseudomonas aeruginosa</i> at concentrations of 12 and 24 mg/mL. The other plants also inhibited various fungi, including <i>Alternaria alternata</i> and <i>Fusarium oxysporum</i>, though to a lesser extent.</p>\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":"143856773","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":"Buffer 4-Ethylmorpholinium/Acetate: Exploring a New Alternative Buffer for Native Mass Spectrometry","authors":"Darya Hadavi,&nbsp;Che Yee Ng,&nbsp;Yuandi Zhao,&nbsp;Anjusha Mathew,&nbsp;Ian G. M. Anthony,&nbsp;Berta Cillero-Pastor,&nbsp;Eva Cuypers,&nbsp;Tiffany Porta Siegel,&nbsp;Maarten Honing","doi":"10.1002/rcm.10048","DOIUrl":"https://doi.org/10.1002/rcm.10048","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>To perform native mass spectrometry (MS) studies, there are a limited number of volatile and electrospray ionization (ESI)-MS compatible solutions, such as ammonium bicarbonate and ammonium acetate (AA). These solutions could induce the unfolding of proteins due to the formation of CO₂ bubbles or induced acidification during ESI. Hence, it was important to introduce a buffer suitable to preserve the native form of proteins while simulating physiological conditions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The 4-ethylmorpholinium/acetate (4EM/A) buffer was compared to AA for the analysis of proteins and protein complexes with mass ranges from 5 to 103 kDa and isoelectric points (pI) between 3 and 11. The evaluations were conducted by comparing the native-MS profiles, CCS values, arrival time distributions (ATDs), and proteins bioactivities. The human cardiac troponin complex (cTn complex) and its subunit cardiac troponin T (cTnT) were analyzed as proof of the applicability of this buffer for challenging proteins and protein complexes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>4EM/A led to lower charge states compared to AA, supporting the likelihood of preserving protein folding during nano-ESI and in a high vacuum environment of MS. Ion mobility measurements revealed that proteins in 4EM/A exhibit a lower degree of conformational variation compared to AA, suggesting enhanced conformational stability and potential retention of natural-like compactness. Additionally, testing the impact of 4EM/A on bioactivity, lysozyme showed increased biological activity in 4EM/A relative to AA, highlighting the buffer's potential for real-time assessment of protein interaction kinetics and bioactivity. The 4EM/A buffer enabled native-MS analysis of cTnT for the first time.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>We introduced 4EM/A, with pK_a of 7.72/4.76, as a promising buffer for native-MS studies to maintain protein and protein complex bioactivity and conformational integrity.</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.10048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852943","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":"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}