Journal of Mass Spectrometry最新文献

Chemical warfare agent (CWA) analysis faces a significant challenge when degradation or precursor compounds lack reference spectra in databases. This study focuses on three structural isomers, N-methyl-N-propylethanimidamide, N-methyl-N-isopropylethanimidamide, and N,N-diethylethanimidamide, which are relevant hydrolysis by-products/precursors of Novichok nerve agents (Schedule 1.A.13/1.A.14) yet are absent from standard spectral libraries. All three isomers were synthesized and then comprehensively characterized by gas chromatography–electron ionization mass spectrometry (GC-EI-MS), gas chromatography–chemical ionization mass spectrometry (GC-CI-MS), and liquid chromatography–high-resolution mass spectrometry (LC-HRMS). Distinctive fragmentation signatures were identified for each isomer. Trimethylsilyl derivatization of the ethanimidamides enhanced GC performance and revealed additional diagnostic ions. LC-HRMS results confirmed the fragment formulas and allowed unambiguous differentiation based on key ion intensity ratios. This work provides the first systematic mass spectral data for these Novichok-related ethanimidamides. The value of these reference spectra was demonstrated in the 57^th OPCW Proficiency Test (PT-57): an unknown spiking chemical was successfully identified as N-methyl-N-propylethanimidamide by comparison to the generated spectra. The study thus delivers new analytical capabilities for CWA forensics—enabling confident identification of challenging isomeric degradation products through a combination of tailored derivatization, multimode mass spectrometry, and expert interpretation of fragmentation pathways.

We present an advanced analytical strategy that exploits the unique capabilities of tandem-trapped ion mobility spectrometry (Tandem-TIMS) to combine high-resolution ion mobility separation with targeted collisional activation and controlled gas-phase trapping. This approach enables the in situ generation of subcomplexes from native-like protein complexes of a selected charge state and allows direct evaluation of their kinetic stability and structural integrity in the gas phase. Using this workflow, we investigated the gas-phase stability of in situ generated streptavidin subunits. Streptavidin tetramers 15+ were mobility-selected and subjected to CID at 160 V between TIMS-1 and TIMS-2, producing monomers, dimers, and trimers. The resulting subcomplexes were then stored in TIMS-2 for up to 10.3 s, during which their collision cross-section distributions remained unchanged, indicating high kinetic stability in the gas phase. Overall, this study highlights the versatility of Tandem-TIMS as an analytical platform for advanced, mobility-resolved measurements that provide new structural and kinetic insights into biological systems.

Silver ion was applied in paper spray ionization mass spectrometry (PSI MS) to assist the ionization of bisphenols and derivatives including bisphenol A (BPA), bisphenol B (BPB), and bisphenol A bis (allylether) (BPA-BAE). By using the silver ion assisted paper spray ionization (SIA PSI), the intensities of BPA, BPB, and BPA-BAE were improved approximately 62, 90, and 58 times under positive mode and 1900, 1980, and 23 250 times under negative mode. Linear relationships for BPA were established within the concentration range of 0.002–1 mM, exhibiting strong correlation coefficients. The limit of detection for BPA can achieve 7.4 × 10⁻⁵ mM. BPA in plastic sample and complex biological samples were also successfully detected by SIA PSI.

Direct-infusion ESI/IT-MS/MS was previously employed to characterize grape anthocyanins that share the same nominal mass but differ in elemental composition. Subsequently, Q-TOF coupled with LC-Chip enabled the complete anthocyanin fingerprint of a single sample to be obtained in under 5 min. In this study, a comprehensive UHPLC/Q-TOF investigation of anthocyanins in three red-berry fruits (blueberry, raspberry, and two fungal-resistant red grape varieties) was performed. In total, 35 anthocyanins were identified. Only two were found in all three fruits, Cy and Pn 3-O-hexosides. The grape berries exhibit high levels of diglucosides, while only raspberries contain Pg derivatives and several di- and trisaccharide anthocyanins. Blueberry uniquely accumulated Pn-malonylhexoside and arabinosyl anthocyanins, and a difference between the two species was found, as cv Biloxi (southern highbush) contained acetyl- and p-coumaroyl glucosides not found in cv Titan (rabbiteye), alongside a preponderance of B-ring tri-substituted anthocyanins. Additionally, in blueberry two isobaric anthocyanins (Pn-hexoside and Mv-arabinoside, MF C₂₂H₂₃O₁₁) were characterized. Sophoroside and rutinoside anthocyanins were found only in the raspberry, where Pn-hexosyl-rutinoside, Cy-3-hexosyl-sophoroside, and a Cy-rutinoside isomer were characterized for the first time. Findings of the study increase the knowledge on these varieties as potential sources of nutraceuticals and natural colorants, also expanding the HR-MS/MS dataset beneficial for their characterization in other fruit varieties.

The misuse of beta-agonist drugs as growth promoters in livestock production, highlighted by the cases of intoxication in Europe in the 1990s, has resulted in strict regulations in the European Union. These restrictions have required the development of increasingly sensitive analytical methods. In June 2022, the European Union Reference Laboratory (EURL BVL Berlin) released the Guidance Document on Minimum Method Performance Requirements (MMPRs), a technical guidance for analytical methods in residue control. The MMPRs represent the minimum concentrations that official laboratories should be able to reliably identify to analyze prohibited substances in different animal matrices. In this work, a qualitative screening method for 21 beta-agonists at half of MMPRs was developed and validated in animal lung and liver by UPLC–MS/MS technique according to Commission Implementing Regulation (EU) 2021/808 requirements. With regard to detection capability CCβ, the results obtained permitted the qualitative determination of 11 clenbuterol-like beta-agonists (Clenbuterol, Bromchlorbuterol, Brombuterol, Cimaterol, Cimbuterol, Clenpenterol, Clenproperol, Hydroxymethylclenbuterol, Mabuterol, Mapenterol, Tulobuterol) at 0.05 μg/kg and for 10 salbutamol-like beta-agonists (Carbuterol, Isoxsuprine, Clencyclohexerol, Ractopamine, Ritodrine, Salbutamol, Terbutaline, Zilpaterol, Fenoterol, Salmeterol) at 0.25 μg/kg. The method was validated for lungs and livers of different animal species (cattle, chicken, sheep, and swine): following the requirements of the above-mentioned Regulation. The method was found to be robust and specific.

Obesity is often linked to protein acetylation and induces intricate changes in post-translational modifications, affecting mitochondrial regulatory instability. Redox signaling is crucial for maintaining cellular homeostasis. The mechanism by which lysine acetylome drives redox signaling may elucidate the complexity of the biological networks underlying obesity. High-fat diet (HFD)–fed mouse livers were lysed, immunoprecipitated with lysine-acetyl antibody-conjugated beads, and labeled with isotopic ¹⁸O/¹⁶O for multiplexing. A total of 2282 proteins and 1384 Kac sites were identified, including 456 newly identified sites that were not matched in the dbPTM and iPTMnet databases. The expression levels of the acetylome were normalized to protein expression, and one-third of the acetylome was quantified. Differentially expressed acetylated proteins were annotated using Gene Ontology; the upregulated proteins belonged to the peroxisomal pathway. The three proteins involved in redox regulation, glutathione S-transferase theta-1, superoxide dismutase 1, and epoxide hydrolase 1, exhibited significant changes at specific sites with acetyl-lysine levels in HFD-fed mouse liver. Our data showed that investigating acetylation pathways can provide insights into the molecular mechanisms driving obesity and offer potential targets for therapeutic interventions.

Mass spectrometry (MS) has emerged as an imperative technology in protein and peptide bioanalysis, offering unparalleled sensitivity, specificity, and dynamic range. However, the complexity of MS datasets, particularly those arising from advanced acquisition methods and diverse biological samples, necessitates the use of specialized data analysis tools. Therefore, selecting the appropriate software is crucial for accurate data interpretation, reproducibility, and regulatory compliance. This review presents a systematic framework to guide researchers in selecting the most suitable MS data analysis tools, spanning key categories such as quantitative analysis, post-translational modification (PTM) identification, and data-independent acquisition (DIA) workflows, tailored to specific experimental goals in protein and peptide bioanalysis.