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Some of the authors of the present research group have previously reported mass spectrometric detection of [PdAu9(PPh3)8(CN)]2+ (PdAu9CN) by atmospheric pressure plasma (APP) irradiation of [MAu8(PPh3)8]2+ (PdAu8) in methanol and proposed based on density functional theory (DFT) calculations that PdAu9CN is constructed by inserting a CNAu or NCAu unit into the Au–PPh3 bond of PdAu8 [Emori et al., J. Chem. Phys. 155, 124312 (2021)]. In this follow-up study, we revisited the structure of PdAu9CN by high-resolution ion mobility spectrometry on an isolated sample of PdAu9CN with the help of dispersion-corrected DFT calculation. In contradiction to the previous proposal, we conclude that isomers in which an AuCN unit is directly bonded to the central Pd atom of PdAu8 are better candidates. This assignment was supported by Fourier transform infrared and ultraviolet–visible spectroscopies of isolated PdAu9CN. The simultaneous formation of [Au(PPh3)2]+ and PdAu9CN suggests that the AuCN species are formed by APP irradiation at the expense of a portion of PdAu8. These results indicate that APP may offer a unique method for transforming metal clusters into novel ones by generating in situ active species that were not originally added to the solution. [ABSTRACT FROM AUTHOR]

Proflavine, a fluorescent cationic dye with strong absorption in the visible, has been proposed as a potential contributor to diffuse interstellar bands (DIBs). To investigate this hypothesis, it is essential to examine the spectra of cold and isolated ions for comparison. Here, we report absorption spectra of proflavine ions, trapped in a liquid-nitrogen-cooled ion trap filled with helium-buffer gas, as well as fluorescence spectra to provide further information on the intrinsic photophysics. We find absorption- and fluorescence-band maxima at 434.2 ± 0.1 and 434.7 ± 0.3 nm, corresponding to a Stokes shift of maximum 48 cm−1, which indicates minor differences between ground-state and excited-state geometries. Based on time-dependent density functional theory, we assign the emitting state to S2 as its geometry closely resembles that of S0, whereas the S1 geometry differs from that of S0. As a result, simulated spectra involving S1 exhibit long Franck-Condon progressions, absent in the experimental spectra. The latter displays well-resolved vibrational features, assigned to transitions involving in-plane vibrational modes where the vibrational quantum number changes by one. Dominant transitions are associated with vibrations localized on the NH2 moieties. Experiments repeated at room temperature yield broader spectra with maxima at 435.5 ± 1 nm (absorption) and 438.0 ± 1 nm (fluorescence). We again conclude that prevalent fluorescence arises from S2, i.e., anti-Kasha behavior, in agreement with previous work. Excited-state lifetimes are 5 ± 1 ns, independent of temperature. Importantly, we exclude the possibility that a narrow DIB at 436.4 nm originates from cold proflavine cations as the band is redshifted compared to our absorption spectra. [ABSTRACT FROM AUTHOR]

When electrolyte solutions are confined in micro- and nanochannels their conductivity is significantly different from those in a bulk phase. Here we revisit the theory of this phenomenon by focusing attention on the reduction in the ion mobility with the concentration of salt and a consequent impact to the conductivity of a monovalent solution, from bulk to confined in a narrow slit. We first give a systematic treatment of electrophoresis of ions and obtain equations for their zeta potentials and mobilities. The latter are then used to obtain a simple expression for a bulk conductivity, which is valid in a concentration range up to a few molars and more accurate than prior analytic theories. By extending the formalism to the electrolyte solution in the charged channel the equations describing the conductivity in different modes are presented. They can be regarded as a generalization of prior work on the channel conductivity to a more realistic case of a nonzero reduction of the electrophoretic mobility of ions with salt concentration. Our analysis provides a framework for interpreting measurements on the conductivity of electrolyte solutions in the bulk and in narrow channels. [ABSTRACT FROM AUTHOR]

Plasma medicine is a field that utilizes reactive species generated from atmospheric low-temperature plasmas for applications such as sterilization, blood coagulation, and cancer therapy. Commercial plasma devices are available for wound healing, but research on the chemical modifications induced by these plasmas is scarce. This study explores the chemical modifications in hemoglobin when exposed to a helium plasma dielectric barrier discharge, with the aim of explaining the potential mechanisms through which it contributes to blood coagulation and enhances wound healing. Optical microscopy of cold atmospheric plasma (CAP) treated whole capillary blood showed an increase in red blood cell (RBC) size and the formation of rouleaux structures. The treatment of whole blood leads to hemolysis of RBCs and the release of intracellular protein content. We then treated purified hemoglobin protein at physiological concentrations, which led to the formation of aggregates that could be observed using ion mobility mass spectrometry (IM–MS), size exclusion chromatography, and optical microscopy. The aggregates formed fibril-like structures as observed using atomic force microscopy. The formation of hemoglobin aggregates is hypothesized to be the result of new intermolecular interactions formed following the CAP-mediated protein oxidation. We studied the changes to hemoglobin structure after treatment with a CAP using high-resolution MS and found that the hemoglobin subunits are oxidized with the addition of at least 4 oxygen atoms each. The intact tetrameric hemoglobin structure remains unchanged; however, the monomeric and dimeric proteins adopt a more compact structure, as observed by IM–MS. We propose that CAP treatment of fresh blood leads to hemolysis, and that the extracellular protein, primarily hemoglobin, is oxidized leading to the formation of aggregates. [ABSTRACT FROM AUTHOR]

Low-temperature plasma (LTP) jets are Food and Drug Administration (FDA)-approved medical devices to remove cancerous tissue and aid in wound healing. However, reports on their reaction with proteins are conflicting, ranging from fragmentation, oxidation, aggregation, or a combination thereof. In this study we bridge the gap between plasma-treatment of short peptides to proteins at physiologically relevant concentrations. The LTP in this study is based on a helium dielectric barrier discharge that forms a plasma-jet, which is directed at the solution without direct contact with the plasma, and results in the formation of reactive oxygen species (ROS) OH• and O2•− in solution. The longer the solution is treated, the more solution-phase ROS form. Treating peptide- and protein-containing solutions leads to extensive oxidation. The ROS led to the same oxidative modifications for peptide M with increasing chain length (9, 18, 37, 76 amino acids), which could be identified with high-resolution mass spectrometry. Oxidized species M + x O led to conformational changes such as compaction and elongation, while the unmodified peptide M remained unaltered, as found by ion mobility spectrometry and size exclusion chromatography. For proteins at high concentration, insoluble aggregates formed and could be identified by UV/V is light scattering and atomic force microscopy. The formation of aggregates is dependent on the amino acid chain length, the peptide concentration, and the time for aggregate formation. These findings highlight the importance of both peptide chain length and concentration in determining the fate of peptides following the exposure to LTP, while also offering valuable insights for the field of plasma medicine. [ABSTRACT FROM AUTHOR]

The document from the journal "Analyst" published by The Royal Society of Chemistry in 2024 provides a comprehensive list of research papers and articles on various topics related to chemistry. The papers cover a wide range of subjects, including electrochemical approaches for biomarker detection, detection of volatile organic compounds, catalytic kinetics, and sensor development for various applications. The journal aims to connect the global chemistry community through impactful research and publications, reinvesting profits back into the field. [Extracted from the article]

The subtle structural variations among carbohydrate isomers pose significant challenges for their identification and quantification. Here, we propose a strategy for rapid identification and quantification of isomeric disaccharides via derivatization with 4-(3-methyl-5-oxo-pyrazolin-1-yl) benzoic acid (CPMP) and analysing by ion mobility spectrometry (IMS). After derivatization, the ionization efficiency of disaccharides was significantly improved. The disaccharide isomers were distinguished by determining the different ion mobilities of CPMP-labelled disaccharides. Among them, [M + 2CPMP + H]+ was separated with a resolution of 1.484, almost achieving baseline separation. Subsequently, [M + CPMP + Na]+ was used for the relative quantification of lactose and maltose, showing a good linear relationship with R2 > 0.990. Finally, the method was successfully applied to the identification of lactose and maltose in beer and milk. The method is fast, accurate and effective for the identification of disaccharide isomers in complex samples. [ABSTRACT FROM AUTHOR]

High-resolution ion mobility (resolving power > 200) coupled with mass spectrometry (MS) is a powerful analytical tool for resolving isobars and isomers in complex samples. High-resolution ion mobility is capable of discerning additional structurally distinct features, which are not observed with conventional resolving power ion mobility (IM, resolving power ~ 50) techniques such as traveling wave IM and drift tube ion mobility (DTIM). DTIM in particular is considered to be the "gold standard" IM technique since collision cross section (CCS) values are directly obtained through a first-principles relationship, whereas traveling wave IM techniques require an additional calibration strategy to determine accurate CCS values. In this study, we aim to evaluate the separation capabilities of a traveling wave ion mobility structures for lossless ion manipulation platform integrated with mass spectrometry analysis (SLIM IM-MS) for both lipid isomer standards and complex lipid samples. A cross-platform investigation of seven subclass-specific lipid extracts examined by both DTIM-MS and SLIM IM-MS showed additional features were observed for all lipid extracts when examined under high resolving power IM conditions, with the number of CCS-aligned features that resolve into additional peaks from DTIM-MS to SLIM IM-MS analysis varying between 5 and 50%, depending on the specific lipid sub-class investigated. Lipid CCS values are obtained from SLIM IM (TW(SLIM)CCS) through a two-step calibration procedure to align these measurements to within 2% average bias to reference values obtained via DTIM (DTCCS). A total of 225 lipid features from seven lipid extracts are subsequently identified in the high resolving power IM analysis by a combination of accurate mass-to-charge, CCS, retention time, and linear mobility-mass correlations to curate a high-resolution IM lipid structural atlas. These results emphasize the high isomeric complexity present in lipidomic samples and underscore the need for multiple analytical stages of separation operated at high resolution. [ABSTRACT FROM AUTHOR]

The importance of lipids in biology continues to grow with their recent linkages to more diseases and conditions, microbiome fluctuations, and environmental exposures. These associations have motivated researchers to evaluate lipidomic changes in numerous matrices and studies. Lipidomic analyses, however, present numerous challenges as lipid species have broad chemistries that require different extraction methods and instrumental analyses to evaluate and separate their many isomers and isobars. Increasing knowledge about different lipid characteristics is therefore crucial for improving their separation and identification. Here, we present a multidimensional database for lipids analyzed on a platform combining reversed-phase liquid chromatography, drift tube ion mobility spectrometry, collision-induced dissociation, and mass spectrometry (RPLC-DTIMS-CID-MS). This platform and the different separation characteristics it provides enables more confident lipid annotations when compared to traditional tandem mass spectrometry platforms, especially when analyzing highly isomeric molecules such as lipids. This database expands on our previous publication containing only human plasma and bronchoalveolar lavage fluid lipids and provides experimental RPLC retention times, IMS collision cross section (CCS) values, and m/z information for 877 unique lipids from additional biofluids and tissues. Specifically, the database contains 1504 precursor [M + H]+, [M + NH4]+, [M + Na]+, [M-H]−, [M-2H]2−, [M + HCOO]−, and [M + CH3COO]− ion species and their associated CID fragments which are commonly targeted in clinical and environmental studies, in addition to being present in the chloroform layer of Folch extractions. Furthermore, this multidimensional RPLC-DTIMS-CID-MS database spans 5 lipid categories (fatty acids, sterols, sphingolipids, glycerolipids, and glycerophospholipids) and 24 lipid classes. We have also created a webpage (tarheels.live/bakerlab/databases/) to enhance the accessibility of this resource which will be populated regularly with new lipids as we identify additional species and integrate novel standards. [ABSTRACT FROM AUTHOR]

Aberrant lipid metabolism has been widely recognized as a hallmark of various diseases. However, the comprehensive analysis of distinct lipids is challenging due to the complexity of lipid molecular structures, wide concentration ranges, and numerous isobaric and isomeric lipids. Usually, liquid chromatography-mass spectrometry (LC-MS)-based lipidomics requires a long time for chromatographic separation to achieve optimal separation and selectivity. Ion mobility (IM) adds a new separation dimension to LC-MS, significantly enhancing the coverage, sensitivity, and resolving power. We took advantage of the rapid separation provided by ion mobility and optimized a fast and broad-coverage lipidomics method using the LC-IM-MS technology. The method required only 8 minutes for separation and detected over 1000 lipid molecules in a single analysis of common biological samples. The high reproducibility and accurate quantification of this high-throughput lipidomics method were systematically characterized. We then applied the method to comprehensively measure dysregulated lipid metabolism in patients with colorectal cancer (CRC). Our results revealed 115 significantly changed lipid species between preoperative and postoperative plasma of patients with CRC and also disclosed associated differences in lipid classes such as phosphatidylcholines (PC), sphingomyelins (SM), and triglycerides (TG) regarding carbon number and double bond. Together, a fast and broad-coverage lipidomics method was developed using ion mobility-mass spectrometry. This method is feasible for large-scale clinical lipidomic studies, as it effectively balances the requirements of high-throughput and broad-coverage in clinical studies. [ABSTRACT FROM AUTHOR]

The report presents first high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based method for the determination of plasma 2-(3-hydroxy-5-phosphonooxymethyl-2-methyl-4-pyridyl)-1,3-thiazolidine-4-carboxylic acid (HPPTCA), an adduct of cysteine and active form of vitamin B6 pyridoxal 5′-phosphate. The assay employs 4-deoxypyridoxine (4-DPD) as an internal standard. Sample preparation procedure primarily involves acetonitrile (ACN) extraction of HPPTCA from plasma proteins, sample deproteinization by ultrafiltration, and dilution of ultrafiltrate with mobile phase prior to chromatographic analysis. The chromatographic separations of HPPTCA and 4-DPD are achieved within 6 min at 20 °C on X-Bridge Glycan BEH Amide (100 × 2.1 mm, 2.5 μm) column using gradient elution. The eluent consists of 0.1% formic acid in a mixture of solvent A (water and ACN (95:5, v: v)) and solvent B (water and ACN (5:95, v: v)) delivered at a flow rate of 0.3 mL/min. The assay linearity was observed within 0.25-10 µmol/L in plasma. The limit of quantification was found to be 0.25 µmol/L. The method was successfully applied to plasma samples delivered by apparently healthy donors showing that the HPLC-MS/MS assay is suitable for human plasma screening. The presence of HPPTCA was confirmed in eleven of fifteen study samples. The HPPTCA concentration ranged from 0.55 to 8.39 µmol/L. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aim Methods Results Conclusions Trial Registration Non‐invasive biomarkers may reduce post‐colonoscopy colorectal cancer (CRC) rates and colonoscopy overuse in Lynch syndrome. Unlike faecal immunochemical test (FIT), faecal volatile organic compounds (VOCs) may accurately detect both advanced and non‐advanced colorectal neoplasia.The aim of this study was to evaluate the potential of faecal VOCs—separately and with FIT—to guide optimal colonoscopy intervals in Lynch syndrome.Prospective longitudinal multicentre study in which individuals with Lynch syndrome collected faeces before and after high‐quality surveillance colonoscopy. VOC‐patterns were analysed using field asymmetric ion mobility spectrometry (FAIMS) and gas chromatography‐ion mobility spectrometry (GC‐IMS) followed by machine learning pipelines, and combined with FIT at 2.55 μg Hb/g faeces. Gas chromatography time‐of‐flight mass spectrometry analysed individual VOC abundance.Among 200 included individuals (57% female, median 51 years), 62 had relevant neoplasia at colonoscopy: 3 CRC, 6 advanced adenoma (AA), 3 advanced serrated lesion (ASL), and 50 non‐advanced adenoma (NAA). Respective sensitivity and negative predictive value for CRC and AA (and also ASL in case of FAIMS) were 100% and 100% using FAIMS (54% specificity), and 89% and 99% using GC‐IMS (58% specificity). Respective sensitivity and specificity for any relevant neoplasia were 88% and 44% (FAIMS) and 84% and 28% (GC‐IMS); accuracy did not significantly improve upon VOC‐FIT. VOC‐patterns differed before and after polypectomy (AUC 0.70). NAA showed decreased faecal abundance of butanal, 2‐oxohexane, dimethyldisulphide and dimethyltrisulphide.In Lynch syndrome, faecal VOCs may be a promising strategy for postponing colonoscopy and for follow‐up after polypectomy. Our results serve as a stepping stone for large validation studies.NL8749 [ABSTRACT FROM AUTHOR]

Premise: Plants generate a wide array of signals such as olfactory cues to attract and manipulate the response of pollinators. The present study addresses the temporal patterns of scent emission as an additional dimension to the scent composition. The expectation is that divergent floral function is reflected in divergent qualitative and temporal emission patterns. Methods: We used GC‐ion mobility spectrometry with an integrated pre‐concentration for automated acquisition of the temporal trends in floral volatile emissions for N. viridiflorus, N. papyraceus, and N. cantabricus subsp. foliosus. Results: We found a considerable increase in scent emissions and changes in scent composition for N. viridiflorus at night. This increase was particularly pronounced for aromatic substances such as benzyl acetate and p‐cresol. We found no diurnal patterns in N. papyraceus, despite a similar qualitative composition of floral volatiles. Narcissus cantabricus subsp. foliosus showed no diurnal patterns either and differed considerably in floral scent composition. Conclusions: Scent composition, circadian emission patterns, and floral morphology indicate divergent, but partially overlapping pollinator communities. However, the limited pollinator data from the field only permits a tentative correlation between emission patterns and flower visitors. Narcissus papyraceus and N. cantabricus show no clear diurnal patterns and thus no adjustment to the activity patterns of their diurnal pollinators. In N. viridiflorus, timing of scent emission indicates an adaptation to nocturnal flower visitors, contradicting Macroglossum as the only reported pollinator. We propose that the legitimate pollinators of N. viridiflorus are nocturnal and are still unidentified. [ABSTRACT FROM AUTHOR]

The study of metal ion's role in the biological processes of Alzheimer's disease has spurred investigations into the coordination chemistry of amyloid beta peptide and its fragments. Nano‐electrospray ionization mass spectrometry (nESI‐MS) has been utilized to examine the stabilization of bound anions on multiprotein complexes without bulk solvent. However, the effects of anions on metal ion binding interactions with amyloid beta peptide have not been explored. This study directly examined metal‐peptide complexes using nESI‐MS and investigated the effects of various anions on the binding ratio and stability of these complexes from ammonium salt solutions. The results indicate that different anions have distinct effects on the binding ratio and stability of various metal‐peptide complexes. Of these, the bicarbonate ion exhibits the highest binding ratios for metal‐peptide complexes, while binding ratios for these complexes in phosphate are comparatively low. Our results suggest that acetate, formate, bicarbonate, and phosphate have weak affinities and act as weak stabilizers of the metal‐peptide complex structure in the gas phase. Intriguingly, chloride and sulfate act as stabilizers of the metal‐peptide complex in the gas phase. The rank order determined from these data is substantially different from the Hofmeister salt series in solution. Although this outcome was anticipated due to the reduced influence of anions and water solvation, our findings correlate well with expected anion binding in solution and emphasize the importance of both hydration layer and anion‐metal‐peptide binding effects for Hofmeister‐type stabilization in solution. This approach proved useful in examining the interactions between metal ions and amyloid beta peptide, which are relevant to Alzheimer's disease, using direct ESI‐MS. [ABSTRACT FROM AUTHOR]

The World Health Organization has emphasized the importance of consuming small fruits for the prevention of chronic health problems, including diabetes, cardiovascular diseases, cancer, and obesity, which are named chronic non-communicable diseases (NCDs). Azara serrata Ruiz & Pav., commonly called "aroma de Castilla", is a shrub endemic to Chile from the Salicaceae family that produces an underutilized blue-grey berry that grows wild in southern Chile. The species is widely used as a medicinal plant by the Andean communities of southern Chile. In this work, a high-resolution mass spectrometric analysis of the methanolic extract revealed several phenolic compounds for the first time in the edible berry of this endemic species. Furthermore, several glycosylated anthocyanins were detected and quantified using UHPLC coupled with UV/Vis detection and trapped ion mobility mass spectrometry (UHPLC-DAD-TIMS-TOF) for the anthocyanin-rich extract, which was prepared using an optimized anthocyanin extraction protocol. The extract proved to be active in the inhibition of several enzymes linked to NCDs, such as acetylcholinesterase, tyrosinase, amylase, lipase, and glucosidase (IC50 = 3.92 ± 0.23, 12.24 ± 0.03, 11.12 ± 0.10, 32.43 ± 0.0, and 371.6 ± 0.0 μg/mL, respectively). Furthermore, the extract concentrated in anthocyanins showed good antioxidant activity evidenced by the bleaching of the radicals DPPH and ABTS, ferric-reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC). The results show that these neglected endemic small berries can be a source of healthy phytochemicals. These Chilean berries can be used as functional food and their extracts are candidates for use as functional ingredients in naturally healthy products. [ABSTRACT FROM AUTHOR]

Ion mobility spectroscopy is a technique to characterize compounds based on the differences in the migration of sample ions under the combined action of electric field and air flow. Ions can be separated according to their quantity of electric charge, mass, size and shape. Meanwhile, the collision cross section of the ions can also be calculated to obtain chemical compound structural information, which has shown excellent performance in separating isomers of substances. In recent years, a variety of ion mobility technologies combined with mass spectrometry technology have emerged, and been widely used in food, biology, medicine, environment and other fields. In this paper, the types and working principles of ion mobility spectroscopy are introduced, the advantages and disadvantages of various types of instruments are analyzed, and the application of ion mobility spectrometry, liquid chromatography and mass spectrometry multidimensional combination in analyzing and identifying nutritive and active ingredients and chemical hazards in food is reviewed. The application prospect and development trend of this technology are also prospected. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusions Cold atmospheric plasma (CAP) is a novel approach for cancer treatment. It can be used to treat liquids—plasma‐activated media (PAM)—which are then transferred to the target as an exogenous source of reactive oxygen and nitrogen species (RONS). The present study aimed at chemically characterizing different PAM and assessing their in vitro selectivity against head and neck cancer cells (HNC).PAM were obtained by exposing 2 and 5 mL of cell culture medium to CAP for 5, 10 and 20 min at a 6 mm working distance. Anions kinetics was evaluated by ion chromatography. Cell proliferation inhibition, apoptosis occurrence, and cell cycle modifications were assessed by MTS and flow cytometry, on human epidermal keratinocyte (HaCaT) and HNC cell lines HSC3, HSC4 and A253.The 2 mL conditions showed a significant reduction in cell proliferation whereas for the 5 mL the effect was milder, but the time‐dependence was more evident. HaCaT were unaffected by the 5 mL PAM, indicating a selectivity for cancer cells.The media chemical composition modified by CAP exposure influenced cell proliferation by modulating cell cycle and inducing apoptosis in cancer cells, without affecting normal cells. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A highly efficient and sensitive ion mobility spectrometry (IMS) system with laser desorption sampling was applied for rapid explosive detection using different surface materials. This portable IMS detector, powered by a battery, offers mobility and is suitable for use in the field or combat zones. The laser desorption (LD) sampling of common explosives (Trinitrotoluene—TNT; Dinitrotoluenes—DNTs; Hexogene—RDX; pentaerythritol tetranitrate—PETN; plastic explosives—Compound 4 (C-4) and Semtex) on a wide range of common surface materials, such as metal, ceramic, plastic, glass, drywall, paper, wood, and textiles, was studied. Successful detection was achieved on nearly all surfaces except flammable materials (paper, wood, and textiles). The limit of detection (LOD) was determined for each explosive and specific surface, demonstrating an impressive LOD of 7 ng/mm2 for TNT. RDX, C-4, PETN, and Semtex achieved LOD values of 15 ng/mm2, while DNTs showed an LOD of approximately 50 ng/mm2. [ABSTRACT FROM AUTHOR]

Mass spectrometry (MS) has revolutionized clinical chemistry, offering unparalleled capabilities for biomolecule analysis. This review explores the growing significance of mass spectrometry (MS), particularly when coupled with liquid chromatography (LC), in identifying disease biomarkers and quantifying biomolecules for diagnostic and prognostic purposes. The unique advantages of MS in accurately identifying and quantifying diverse molecules have positioned it as a cornerstone in personalized-medicine advancement. MS-based technologies have transformed precision medicine, enabling a comprehensive understanding of disease mechanisms and patient-specific treatment responses. LC-MS has shown exceptional utility in analyzing complex biological matrices, while high-resolution MS has expanded analytical capabilities, allowing the detection of low-abundance molecules and the elucidation of complex biological pathways. The integration of MS with other techniques, such as ion mobility spectrometry, has opened new avenues for biomarker discovery and validation. As we progress toward precision medicine, MS-based technologies will be crucial in addressing the challenges of individualized patient care, driving innovations in disease diagnosis, prognosis, and treatment strategies. [ABSTRACT FROM AUTHOR]

Rationale: Optimizing the structure of digital polymers is an efficient strategy to ensure their tandem mass spectrometry (MS/MS) readability. In block‐truncated poly(phosphodiester)s, homolysis of C–ON bonds in long chains permits the release of smaller blocks amenable to sequencing. Yet the dissociation behavior of diradical blocks was observed to strongly depend on their charge state. Methods: Polymers were ionized in negative mode electrospray and activated in‐source so that blocks released as primary fragments can be investigated using ion mobility spectrometry (IMS) or sequenced in the post‐IMS collision cell. Collision cross sections (CCS) were derived from arrival times using a calibration procedure developed for polyanions using the IMSCal software. A multistep protocol based on quantum methods and classical molecular dynamics was implemented for molecular modeling and calculation of theoretical CCS. Results: Unlike their triply charged homologues, dissociation of diradical blocks at the 2– charge state produces additional fragments, with +1 m/z shift for those holding the nitroxide α‐termination and −1 m/z for those containing the carbon‐centered radical ω‐end. These results suggest cyclization of these diradical species, followed by H• transfer on activated reopening of this cycle. This assumption was validated using IMS resolution of the cyclic/linear isomers and supported by molecular modeling. Conclusions: Combining IMS with molecular modeling provided new insights into how the charge state of digital blocks influences their dissociation. These results permit to define new guidelines to improve either ionization conditions or the structural design of these digital polymers for best MS/MS readability. [ABSTRACT FROM AUTHOR]

Nature uses various chiral and unsymmetric building blocks to form substantial and complex supramolecular assemblies. In contrast, the majority of organic ligands used in metallosupramolecular chemistry are symmetric and achiral. Here we extend the group of unsymmetric chiral bile acids used as a scaffold for organic bispyridyl ligands by employing chenodeoxycholic acid (CDCA), an epimer of the previously used ursodeoxycholic acid (UDCA). The epimerism, flexibility, and bulkiness of the ligands leads to large structural differences in coordination products upon reaction with Pd(NO3)2. The UDCA‐bispyridyl ligand self‐assembles quantitatively into a single crown‐like Pd3L6 complex, whereas the CDCA ligand provides a mixture of coordination complexes of general formula PdnL2n, i.e., Pd2L4, Pd3L6, Pd4L8, Pd5L10, and even Pd6L12 containing an impressive 120 chiral centers. The coordination products were studied by a combination of analytical methods, with ion‐mobility mass spectrometry (IM‐MS) providing valuable details on their structure and allowed an effective separation of m/z 1461 to individual signals according to the arrival time distribution, thereby revealing four different ions of [Pd3L6(NO3)3]3+, [Pd4L8(NO3)4]4+, [Pd5L10(NO3)5]5+, and [Pd6L12(NO3)6]6+. The structures of all the complexes were modelled using DFT calculations. Finally, the challenges and conclusions in determining the specific structural identity of these unsymmetric species are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the improvement of food safety requirements, rapid, nondestructive, accurate, and high-throughput determination of volatile ingredients plays an important role in the analysis area. Owing to the advantages of high separation efficiency, high sensitivity, no sample pretreatment requirement, and fast response, gas chromatography–ion mobility spectrometry (GC–IMS) is important in the nondestructive and rapid detection of volatile organic compounds in the fields of biology, pathology, and food science. In the end, current GC–IMS applications in food safety control and quality analysis are systematically reviewed based on developments in working principles, experimental processes, and methods in cheminformatics and bioinformatics. In addition, the latest developments and advances, practical challenges and limitations, and requirements for GC–IMS applications are also critically discussed, providing new insights into GC–IMS application in food science. [ABSTRACT FROM AUTHOR]

To address the challenge of relying on complex biochemical methods for identifying rice species, a prediction model that combines gas chromatography-ion mobility spectroscopy (GC-IMS) with a convolutional neural network (CNN) was developed. The model utilizes the GC-IMS fingerprint data of each rice variety sample, and an improved CNN structure is employed to increase the recognition accuracy. First, an improved generative adversarial network based on the diffusion model (DGAN) is used for data enhancement to expand the dataset size. Then, on the basis of a residual network called ResNet50, a transfer learning method is introduced to improve the training effect of the model under the condition of a small sample. In addition, a new attention mechanism called Triplet is introduced to further highlight useful features and improve the feature extraction performance of the model. Finally, to reduce the number of model parameters and improve the efficiency of the model, a method called knowledge distillation is used to compress the model. The results of our experiments revealed that the recognition accuracy for identifying the 10 rice varieties was close to 96%; hence, the proposed model significantly outperformed traditional models such as principal component analysis and support vector machine. Furthermore, compared to the traditional CNN, our model reduced the number of parameters and number of computations by 53% and 55%, respectively, without compromising classification accuracy. The study also suggests that the combination of GC-IMS and our proposed deep learning method had better discrimination abilities for rice varieties than traditional chromatography and other spectral analysis methods and that it effectively identified rice varieties. [ABSTRACT FROM AUTHOR]

Understanding and controlling the chemical behavior of iron and iron oxide clusters requires accurate thermochemical data, which, because of the complex electronic structure of transition metal clusters, can be difficult to calculate reliably. Here, dissociation energies for Fe 2 + , Fe2O+, and Fe 2 O 2 + are measured using resonance enhanced photodissociation of clusters contained in a cryogenically cooled ion trap. The photodissociation action spectrum of each species exhibits an abrupt onset for the production of Fe+ photofragments from which bond dissociation energies are deduced for Fe 2 + (2.529 ± 0.006 eV), Fe2O+ (3.503 ± 0.006 eV), and Fe 2 O 2 + (4.104 ± 0.006 eV). Using previously measured ionization potentials and electron affinities for Fe and Fe2, bond dissociation energies are determined for Fe2 (0.93 ± 0.01 eV) and Fe 2 − (1.68 ± 0.01 eV). Measured dissociation energies are used to derive heats of formation ΔfH0( Fe 2 + ) = 1344 ± 2 kJ/mol, ΔfH0(Fe2) = 737 ± 2 kJ/mol, ΔfH0( Fe 2 − ) = 649 ± 2 kJ/mol, ΔfH0(Fe2O+) = 1094 ± 2 kJ/mol, and ΔfH0( Fe 2 O 2 + ) = 853 ± 21 kJ/mol. The Fe 2 O 2 + ions studied here are determined to have a ring structure based on drift tube ion mobility measurements prior to their confinement in the cryogenic ion trap. The photodissociation measurements significantly improve the accuracy of basic thermochemical data for these small, fundamental iron and iron oxide clusters. [ABSTRACT FROM AUTHOR]

Polymer cation exchange membranes (CEMs) are widely used in water treatment processes. The fundamental factors that control the separation and selectivity of cations with different valences in CEMs are not fully understood. In this study, we use atomistic molecular dynamics simulations to investigate the underlying molecular mechanisms that control the mobility of cations with different valences in Nafion membranes. Our results indicate structural differences in binding of monovalent and divalent cations, which gives rise to differences in ion diffusion in Nafion. Monovalent cations are shown to be "territorially" bound, i.e., bound while partially hydrated, to the fixed charge groups whereas divalent cations are shown to be "site" bound, i.e., bound while fully dehydrated, to the charge groups on the polymer. This difference in binding structure gives rise to differences in transport characteristics of cations in Nafion. [ABSTRACT FROM AUTHOR]

Rationale: Spironolactone is a steroidal drug prescribed for a variety of medical conditions and is extensively metabolized quickly after administration. Measurement of spironolactone and its metabolites remains challenging using mass spectrometry (MS) due to in-source fragmentation and relatively poor ionization using electrospray ionization. Therefore, improved methods of measurements are needed, particularly in the case of small sample volumes. Methods: Girard's reagent P (GP) derivatization of spironolactone was employed to improve response and provide an MS-based solution to the measurement of spironolactone and its metabolites. We performed ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESIMS/MS) and ion mobility spectrometry (IMS)-high-resolution mass spectrometry (HRMS) to fully characterize the GP derivatization products. Analytes were studied in positive ionization mode, and MS/MS was performed using nonresonance and resonance excitation collision-induced dissociation. Results: We observed the successful GP derivatization of spironolactone and its metabolites using authentic chemical standards. A signal enhancement of 1-2 orders of magnitude was observed for GP-derivatized versions of spironolactone and its metabolites. Further, GP derivatization eliminated in-source fragmentation. Finally, we performed GP derivatization and ultra-high-performance liquid chromatography- high-resolution mass spectrometry (UHPLC-HRMS) in a small volume of murine serum (20 µL) from spironolactone-treated and control animals and observed multiple spironolactone metabolites only in the spironolactone-treated group. Conclusions: GP derivatization was proven to have advantageous mass spectral performance (e.g., limiting in-source fragmentation, enhancing signals, and eliminating isobaric analytes) for spironolactone and its metabolites. This work and the detailed characterization using ultra-high-performance liquid chromatography- high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) and IMS serve as the foundation for future developments in reaction optimization and/or quantitative assay development. [ABSTRACT FROM AUTHOR]

Small extracellular vesicles (EVs) play a pivotal role in intercellular communication across various physiological and pathological contexts. Despite their growing significance as disease biomarkers and therapeutic targets in biomedical research, the lack of reliable isolation techniques remains challenging. This study characterizes vesicles that were isolated from conditioned culture media (CCM) sourced from three myeloma cell lines (MM.1S, ANBL-6, and ALMC-1), and from the plasma of healthy donors and multiple myeloma patients. We compared the efficacy, reproducibility, and specificity of isolating small EVs using sucrose cushion ultracentrifugation (sUC) vs. ultrafiltration combined with size-exclusion chromatography (UF-SEC). Our results demonstrate that UF-SEC emerges as a more practical, efficient, and consistent method for EV isolation, outperforming sUC in the yield of EV recovery and exhibiting lower variability. Additionally, the comparison of EV characteristics among the three myeloma cell lines revealed distinct biomarker profiles. Finally, our results suggest that HBS associated with Tween 20 improves EV recovery and preservation over PBS. Standardization of small EV isolation methods is imperative, and our comparative evaluation represents a significant step toward achieving this goal. [ABSTRACT FROM AUTHOR]

There is a significant unmet need for clinical reflex tests that increase the specificity of prostate-specific antigen blood testing, the longstanding but imperfect tool for prostate cancer diagnosis. Towards this endpoint, we present the results from a discovery study that identifies new prostate-specific antigen reflex markers in a large-scale patient serum cohort using differentiating technologies for deep proteomic interrogation. We detect known prostate cancer blood markers as well as novel candidates. Through bioinformatic pathway enrichment and network analysis, we reveal associations of differentially abundant proteins with cytoskeletal, metabolic, and ribosomal activities, all of which have been previously associated with prostate cancer progression. Additionally, optimized machine learning classifier analysis reveals proteomic signatures capable of detecting the disease prior to biopsy, performing on par with an accepted clinical risk calculator benchmark. [ABSTRACT FROM AUTHOR]

Recently, our group has shown that fentanyl and many of its analogues form prototropic isomers ("protomers") during electrospray ionization. These different protomers can be resolved using ion mobility spectrometry and annotated using mobility‐aligned tandem mass spectrometry fragmentation. However, their formation and the extent to which experimental variables contribute to their relative ratio remain poorly understood. In the present study, we systematically investigated the effects of mixtures of common chromatographic solvents (water, methanol, and acetonitrile) and pH on the ratio of previously observed protomers for 23 fentanyl analogues. Interestingly, these ratios (N‐piperidine protonation vs. secondary amine/O = protonation) decreased significantly for many analogues (e.g., despropionyl ortho‐, meta‐, and para‐methyl fentanyl), increased significantly for others (e.g., cis‐isofentanyl), and remained relatively constant for the others as solvent conditions changed from 100% organic solvent (methanol or acetonitrile) to 100% water. Interestingly, pH also had significant effects on this ratio, causing the change in ratio to switch in many cases. Lastly, increasing conditions to pH ≥ 4.0 also prompted the appearance of new mobility peaks for ortho‐ and para‐methyl acetyl fentanyl, where all previous studies had only showed one single distribution. Because these ratios have promise to be used qualitatively for identification of these (and emerging) fentanyl analogues, understanding how various conditions (i.e., mobile phase selection and/or chromatographic gradient) affect their ratios is critically important to the development of advanced ion mobility and mass spectrometry methodologies to identify fentanyl analogues. [ABSTRACT FROM AUTHOR]

Human milk oligosaccharides (HMOs) are an important class of biomolecules responsible for the healthy development of the brain‐gut axis of infants. Unfortunately, their accurate characterization is largely precluded due to a variety of reasons – there are over 200 possible HMO structures whereas only 10s of these are available as authentic analytical standards. Furthermore, their isomeric heterogeneity stemming from their many possible glycosidic linkage positions and corresponding α/β anomericities further complicates their analyses. While liquid chromatography coupled to tandem mass spectrometry remains the gold standard for HMO analyses, it often times cannot resolve all possible isomeric species and thus warrants the development of other orthogonal approaches. High‐resolution ion mobility spectrometry coupled to mass spectrometry has emerged as a rapid alternative to condensed‐phase separations but largely has remained limited to qualitative information related to the resolution of isomers. In this work, we have assessed the use of permethylation to improve both the resolution and sensitivity of HMO analyses with cyclic ion mobility separations coupled with mass spectrometry. In addition to this, we have developed the first‐ever high‐resolution collision cross‐section database for permethylated HMOs using our previously established calibration protocol. We envision that this internal reference database generated from high‐resolution cyclic ion mobility spectrometry‐mass spectrometry will greatly aid in the accurate characterization of HMOs and provide a valuable, orthogonal, approach to existing liquid chromatography–tandem mass spectrometry‐based methods. [ABSTRACT FROM AUTHOR]

An ion mobility mass spectrometry (IM‐MS) investigation using a Synapt G2 mass spectrometer was conducted to separate anions generated from the three regioisomers of sulfobenzoic acid. The results revealed that the differences in arrival time distributions (ATDs) were inadequate to differentiate the isomers unambiguously. However, the ATD profiles of the product ions, generated by fragmenting the respective mass‐selected m/z 201 precursor ions in the Trap region of the three‐compartment traveling‐wave ion guide of the Synapt G2 mass spectrometer, were distinctly different, enabling definitive differentiation of the isomers. An arrival‐time peak for an ion of m/z 157 resulting from the loss of CO2 from the respective precursors was common to all three mobilograms. However, only the profile recorded from the para‐isomer exhibited a unique arrival‐time peak for an ion of m/z 137, originating from an SO2 loss. Such a peak corresponding to an SO2 loss was absent in the ATD profiles of the ortho‐ and meta‐isomers. Additionally, the mobilogram of the meta‐isomer displayed a unique peak at 3.42 ms. Based on its product ion spectrum, this peak was attributed to the bisulfite anion (m/z 81; HSO3ˉ). Previously, this meta‐isomer specific m/z 81 ion had been proposed to originate from a two‐step process involving the intermediacy of an m/z 157 ion formed by CO2 loss. However, our detailed tandem mass spectrometric experiments suggest that the m/z 81 is not a secondary product but rather an ion that originated from a direct elimination of a benzyne derivative from the m/z 201 precursor ion. [ABSTRACT FROM AUTHOR]

Heat treatment is widely applied in food processing, but its significant effects on flavor are often overlooked. This study explored how heat treatment impacts the flavor compounds of Antarctic krill. The volatile substances and flavor profiles of Antarctic krill post steaming or hot air drying were analyzed using headspace solid-phase microextraction, gas chromatography-mass spectrometry (HS-SPME-GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS), and electronic tongue detection techniques. Free amino acids (FAAs) content, the main flavor precursors, were quantified and compared. The results showed that the FAAs content of SK was the lowest at 48.44 ± 2.10 mg/g db, while the FAAs content of HD_105 was the highest at 67.42 ± 1.77 mg/g db. Drying amplified the flavor intensity of umami and bitter amino acids, while steaming significantly increased the content of the sweet amino acid proline (p < 0.05). The electronic tongue discerned that drying had more pronounced effects than steaming on saltiness, umami, bitterness, and astringency. By combining the volatile organic compounds (VOCs) fingerprints with the results of the GC-MS analysis of five samples, it was observed that the richness in fat and aromatic taste of shrimp powder after hot air drying at 60℃ (HD_60) and 80℃ (HD_80) was enhanced. Krill dried at 105℃ (HD_105) predominantly exhibited a roasted flavor profile, while steamed krill (SK) displayed minimal alterations in volatile flavors. In summary, steaming increased the sweet amino acid content in krill, while drying enhanced krill's aroma characteristics. This study furnishes valuable insights for the subsequent processing and utilization of Antarctic krill to augment its flavor quality. [ABSTRACT FROM AUTHOR]

In the field of quality analysis of food and flavoring products, gas chromatography–quadrupole mass spectrometry–ion mobility spectrometry (GC-QMS-IMS) is a powerful technique for the simultaneous detection of volatile organic compounds (VOCs) by both QMS and IMS. GC is an established technique for the separation of complex VOC-rich food products. While subsequent detection by IMS features soft ionization of fragile compounds (e.g., terpenes) with characteristic drift times, MS provides analytes' m/z values for database substance identification. A limitation of the prominently used static-headspace-based GC-QMS-IMS systems is the substantially higher sensitivity of IMS in comparison to full-scan QMS. The present study describes a new prototypic trapped-headspace (THS)-GC-QMS-IMS setup using mango purees. This approach ultimately allows the combination of soft ionization with m/z values obtained from database-searchable electron ionization (EI) spectra. The new setup features aligned retention times for IMS and MS and sufficient signal intensities for QMS and IMS. The results demonstrate that THS-GC-QMS-IMS allows for the classification of mango purees from different cultivars and that it could be a promising alternative method for authenticity control of food, flavors, and beverages. [ABSTRACT FROM AUTHOR]

[Display omitted] A "once-in-a-millennium" super rainstorm battered Zhengzhou, central China, from 07/17/2021 to 07/22/2021 (named "7.20" Zhengzhou rainstorm). It killed 398 people and caused billions of dollars in damage. A pressing question is whether rainstorms of this intensity can be effectively documented by geological archives to understand better their historical variabilities beyond the range of meteorological data. Here, four land snail shells were collected from Zhengzhou, and weekly to daily resolved snail shell δ 18O records from June to September of 2021 were obtained by gas-source mass spectrometry and secondary ion mass spectrometry. The daily resolved records show a dramatic negative shift between 06/18/2021 and 09/18/2021, which has been attributed to the "7.20" Zhengzhou rainstorm. Moreover, the measured amplitude of this shift is consistent with the theoretical value estimated from the flux balance model and instrumental data for the "7.20" Zhengzhou rainstorm. Our results suggest that the ultra-high resolution δ 18O of land snail shells have the potential to reconstruct local synoptic scale rainstorms quantitatively, and thus fossil snail shells in sedimentary strata can be valuable material for investigating the historical variability of local rainstorms under different climate backgrounds. [ABSTRACT FROM AUTHOR]

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AbstractObjectiveMethodsResultsConclusionAngiotensin-converting enzyme (ACE, EC 3.4.15.1) is a very important factor in the regulation of blood pressure. Also, the inhibition of ACE with natural compounds has been a very important research area in the treatment of high blood pressure. ACE was purified and characterized from sheep plasma. Molecular docking studies and the inhibition effect of thiamine, riboflavin, and captopril on ACE were investigated.Herein, ACE was purified from sheep plasma by affinity chromatography. The effect of thiamine and riboflavin on ACE was researched. Molecular docking studies were performed to understand the molecular interactions between thiamine, riboflavin, and captopril with ACE.The purification coefficient was found to be 8636 fold. The binding energy of thiamine, riboflavin, and captopril was found to be -6.7 kcal/mol, -8.1 kcal/mol, and -5.5 kcal/mol, respectively. Thiamine conformed to three conventional hydrogen bonds with ASP:415, HIS:513, and LYS:454. Riboflavin formed four conventional hydrogen bonds with GLN:281, GLU:376, THR:282, and TYR:520. Captopril formed two conventional hydrogen bonds with ARG:124, one conventional hydrogen bond with TYR:62 and ASN:85, and one carbon-hydrogen bond with ASN:66. Molecular docking results showed that thiamine, riboflavin, and captopril interacted with ACE through hydrogen bonding and hydrophobic interactions. Thiamine and riboflavin indicated significant inhibition effects on ACE. The IC50 values of thiamine, riboflavin, and captopril were found as 960.56 µM, 11.02 µM, and 1.60 nM, respectively. Ki values for thiamine, riboflavin, and captopril were determined as 1352.04 µM, 12.30 µM, and 1.06 nM, respectively.In this work, it was concluded that thiamine and riboflavin may have preventive and therapeutical impacts against high blood pressure with their ACE inhibitor effect. Thiamine and riboflavin showed a lower inhibitory effect with a higher IC50 than captopril. However, when the inhibitory effect of thiamine and riboflavin vitamins is compared to captopril, it is concluded that they may be natural inhibitors with fewer side effects. [ABSTRACT FROM AUTHOR]

Amyloidosis is a disease characterized by local and systemic extracellular deposition of amyloid protein fibrils where its excessive accumulation in tissues and resistance to degradation can lead to organ failure. Diagnosis is challenging because of approximately 36 different amyloid protein subtypes. Imaging methods like immunohistochemistry and the use of Congo red staining of amyloid proteins for laser capture microdissection combined with liquid chromatography tandem mass spectrometry (LMD/LC–MS/MS) are two diagnostic methods currently used depending on the expertise of the pathology laboratory. Here, we demonstrate a streamlined in situ amyloid peptide spatial mapping by Matrix Assisted Laser Desorption Ionization–Mass Spectrometry Imaging (MALDI-MSI) combined with Trapped Ion Mobility Spectrometry for potential transthyretin (ATTR) amyloidosis subtyping. While we utilized the standard LMD/LC–MS/MS workflow for amyloid subtyping of 31 specimens from different organs, we also evaluated the potential introduction in the MS workflow variations in data acquisition parameters like dynamic exclusion, or testing Data Dependent Acquisition combined with High-Field Asymmetric Waveform Ion Mobility Spectrometry (DDA FAIMS) versus Data Independent Acquisition (DIA) for enhanced amyloid protein identification at shorter acquisition times. We also demonstrate the use of Mascot's Error Tolerant Search and PEAKS de novo sequencing for the sequence variant analysis of amyloidosis specimens. [ABSTRACT FROM AUTHOR]

The effect of the sweat and grease deposits (SGD) from fingerprints on the detection efficiency of trace amounts of explosive substances—triacetone triperoxide (TATP), hexamethylene triperoxide diamine (HMTD), and ammonium nitrate (AN) by ion mobility spectrometry in air at atmospheric pressure was investigated. Among the main components of SGD, urea is identified as a positive mode influencer, while lactic acid (LA) affects in a negative mode. The presence of urea or SGD in the sample does not significantly affect the detection of TATP in the positive mode but decreases the efficiency of HMTD ion formation and leads to the appearance of adduct cations of HMTD and urea. The presence of lactic acid or SGD slightly decreases the efficiency of ammonium nitrate ion formation in the negative mode and significantly alters the qualitative composition of HMTD ions, leading to the appearance of HMTD and LA adduct anions. In the absence of any impurities in the sample, the best reduced limit of detection (signal-to-noise ratio = 3σ), estimated at 30–50 pg, was observed for HMTD. The lifetime of HMTD, TATP, and AN traces on aluminum foil under laboratory conditions was determined to be 1, 3, and 12 h for samples with masses of mHMTD 1 × 10–9, 2 × 10–9, and 1 × 10–8 g and surface densities ds of 0.008, 0.016, and 0.08 μg/cm2, respectively; 102 and 103 s for mTATP 1 × 10–5 and 1 × 10–4 g and ds of 80 and 800 μg/cm2, respectively; 12 and 25 h for mAN 3 × 10–8 and 5 × 10–8 g and ds of 0.24 and 0.4 μg/cm2, respectively. [ABSTRACT FROM AUTHOR]

Summary: In this study, the effect of different fermenters on the quality and flavour of fermented mandarin fish was investigated via pH, salt content, moisture content, thiobarbituric acid, microbial community, free amino acids and volatile compounds. The results demonstrated that the inoculated fermentation effectively suppressed fish fat oxidation, resulting in significantly higher levels of umami amino acids in mandarin fish compared to the natural fermentation group (P < 0.05). Additionally, certain bitter amino acids were also inhibited. Moreover, the total amino acid content of the mixed inoculated fermentation group was significantly elevated compared to other groups, reaching 300.21 ± 5.37 mg/100 g. The synergistic effect of free amino acids and flavour‐enhancing nucleotides significantly influenced the taste of the fermented fish, with the mixed inoculation fermentation group exhibiting a significantly higher Equivalent umami concentration (EUC) value compared to other groups, reaching 216.06 ± 20.13 mgMSG/100 g on the sixth day of fermentation. A total of 47 volatile compounds were detected by using headspace gas chromatography‐ion mobility spectrometry (HS‐GC‐IMS), and the results demonstrated that inoculated fermentation positively influenced the development of fish flavour, and mixed inoculated fermentation proved to be more effective. This study provides a theoretical foundation for the industrial production of fermented fish products and offers potential avenues for technical enhancement. [ABSTRACT FROM AUTHOR]

Seminal plasma contains a heterogeneous population of extracellular vesicles (sEVs) that remains poorly characterized. This study aimed to characterize the lipidomic profile of two subsets of differently sized sEVs, small (S-) and large (L-), isolated from porcine seminal plasma by size-exclusion chromatography and characterized by an orthogonal approach. High-performance liquid chromatography–high-resolution mass spectrometry was used for lipidomic analysis. A total of 157 lipid species from 14 lipid classes of 4 major categories (sphingolipids, glycerophospholipids, glycerolipids, and sterols) were identified. Qualitative differences were limited to two cholesteryl ester species present only in S-sEVs. L-sEVs had higher levels of all quantified lipid classes due to their larger membrane surface area. The distribution pattern was different, especially for sphingomyelins (more in S-sEVs) and ceramides (more in L-sEVs). In conclusion, this study reveals differences in the lipidomic profile of two subsets of porcine sEVs, suggesting that they differ in biogenesis and functionality. [ABSTRACT FROM AUTHOR]

Huajiao (Zanthoxylum bungeanum Maxim.) is extensively cultivated in various countries, including China, Korea, and India, owing to its adaptability to diverse environments. This study comprehensively analyzed the volatile substance composition of 14 varieties of red huajiao with distinct geographical origins. Thermal analysis methods, gas chromatography‐mass spectrometry (GC‐MS), and headspace‐ion mobility chromatography (HS‐IMS) were employed to evaluate the total volatile substance composition and content. The study revealed minor variations in water content, volatile matter content, and fractions among the geographically sourced huajiao samples. Utilizing correlation analysis based on GC‐MS and orthogonal partial least squares discriminant analysis (OPLS‐DA) with HS‐IMS, a robust classification method for the 14 types of huajiao was developed. Applying the variable importance in the projection (VIP) method, seven distinctive components were identified as potential markers for distinguishing the geographical origins of red huajiao. By integrating climatic and topographical factors of the 14 huajiao varieties, the correlation analysis of GC‐MS, and OPLS‐DA classification outcomes from HS‐IMS elucidated the influence of geo‐environmental factors on huajiao components and contents. This research provides insights into the impact of diverse geographic environments on the constituents and characteristics of huajiao. It offers valuable guidance for selecting optimal cultivation locations to enhance huajiao quality, aiding consumers in making informed choices. [ABSTRACT FROM AUTHOR]

Broader adoption of native mass spectrometry (MS) and ion mobility‐mass spectrometry (IM‐MS) has propelled the development of several techniques which take advantage of the selectivity, sensitivity, and speed of MS to make measurements of complex biological molecules in the gas phase. One such method, collision induced unfolding (CIU), has risen to prominence in recent years, due to its well documented capability to detect shifts in structural stability of biological molecules in response to external stimuli (e.g., mutations, stress, non‐covalent interactions, sample conditions etc.). This increase in reported CIU measurements is enabled partly due to advances in IM‐MS instrumentation by vendors, and also innovative method development by researchers. This perspective highlights a few of these advances and concludes with a look forward toward the future of the gas phase unfolding field. [ABSTRACT FROM AUTHOR]

Honey is rich in nutrients and has a wide range of biological activities. However, due to the different botanical origins, geographical origins, entomological origins, and maturity, honey shows significant differences in their endogenous compositions and nutritional values. Volatile organic compounds (VOCs) are closely related to the characteristic properties of honey, and can be used to characterize the differences between honey. Gas chromatography-ion mobility spectroscopy (GC-IMS) is a new technology which combines gas chromatography with ion mobility spectroscopy for the determination of VOCs. In recent years, GC-IMS has been gradually applied to entomological origins identification, geographical origin tracing, botanical origin differentiation, adulteration identification and maturity evaluation of honey, and has achieved good results, showing great application potential in honey quality evaluation. In this paper, the application research progress of GC-IMS for honey quality evaluation is summarized. It is suggested that future research should be carried out from the aspects of establishing honey GC-IMS database, developing GC-IMS equipment with fusion quantitative function, developing the technical standard of quality evaluation based on GC-IMS, and using GC-IMS in combination with other detection technologies, in order to provide reference for the application of GC-IMS for honey quality control, flavor research and product development. [ABSTRACT FROM AUTHOR]

Gas chromatography–ion mobility spectrometry (GC-IMS) is a smart method that has been applied to determine the volatile compounds in Chinese teas, but its use in comparing the volatile compounds of different types of tea has not been mentioned. In this study, the volatile compounds found in four types of samples (green, yellow, white, and black teas) made with fresh leaves of Camellia sinensis (L.) Kuntze 'Zhongcha 111' were analyzed using GC-IMS. The results showed that 93 volatile compounds were identified from our tea samples and that the average volume of aldehydes was higher than that for other compounds, especially in white tea. The different samples were successfully categorized using multivariate statistical analysis. Using partial least squares discriminant analysis (PLS-DA), we found 15 key compounds, including four differential components: (E)-2-hexenal, 2-furanmethanethio, 2-hexanol, and 1-octene. There were 29 common components, and their total content reached 386.0 μg/g. Moreover, the 3-methyl-2-butenal and dimethyl disulfide detected in the four samples were also differential compounds, varying according to the manufacturing technology. Thus, this study demonstrates that different types of teas can be discriminated easily using GC-IMS and that this is helpful to shorten the time for improving tea quality and developing new products. [ABSTRACT FROM AUTHOR]

To explore the effect of yeast-Agastache rugosus complex solution on the deodorization of tilapia, the deodorization process was optimized by single factor and response surface experiments. Gas chromatography ion mobility spectroscopy (GC-IMS) was used to identify the volatile components of tilapia meat before and after deodorization, and partial least squares discriminant analysis (OPLS-DA) was used to distinguish and analyze the differences. Results showed that when the conditions of a mass concentration of 2.1 g/100 mL, the ratio of solid to liquid was 1:3.09 (g:mL), and the deodorization time of 32 minutes, the fishy degree was the lowest and the sensory score was the highest. A total of 22 volatile compounds, mainly aldehydes and alcohols, were detected by GC-IMS. After deodorization, the relative content of aldehydes decreased from 50.64% to 40.82%, and that of alcohols decreased from 34.00% to 27.77% . According to the odor threshold value, the substances with relative odor activity value (ROAV) was greater than 1 were 1-octen-3-ol, 1-hexanol, heptanal, nonanal, octyl aldehede, ethyl acetate, and acetic acid hexyl ester. Five key fishy substances (VIP > 1) were screened by partial least squares discriminant analysis and variable importance in projection (VIP). They were octyl aldehede, nonanal, heptanal, 1-octen-3- ol, and 1-hexanol. The interaction of these substances had an important impact on the fishy smell of tilapia. [ABSTRACT FROM AUTHOR]

Glycosaminoglycans (GAGs) are linear and acidic polysaccharides. They are ubiquitous molecules, which are involved in a wide range of biological processes. Despite being structurally simple at first glance, with a repeating backbone of alternating hexuronic acid and hexosamine dimers, GAGs display a highly complex structure, which predominantly results from their heterogeneous sulfation patterns. The commonly applied method for compositional analysis of all GAGs is "disaccharide analysis." In this process, GAGs are enzymatically depolymerized into disaccharides, derivatized with a fluorescent label, and then analysed through liquid chromatography. The limiting factor in the high throughput analysis of GAG disaccharides is the time‐consuming liquid chromatography. To address this limitation, we here utilized trapped ion mobility‐mass spectrometry (TIM‐MS) for the separation of isomeric GAG disaccharides, which reduces the measurement time from hours to a few minutes. A full set of disaccharides comprises twelve structures, with eight possessing isomers. Most disaccharides cannot be differentiated by TIM‐MS in underivatized form. Therefore, we developed chemical modifications to reduce sample complexity and enhance differentiability. Quantification is performed using stable isotope labelled standards, which are easily available due to the nature of the performed modifications. [ABSTRACT FROM AUTHOR]

Polymers have a wide range of applications depending on their composition, size, and architecture. Varying any of these three characteristics can greatly impact the resulting chemical, physical, and mechanical properties. While many techniques are available to determine polymer composition and size, determining the exact polymer architecture is more challenging. Herein, tandem mass spectrometry (MS/MS) and ion mobility mass spectrometry (IM-MS) methods are utilized to derive crucial architectural information about dithiol-yne comb polymers. Based on their unique fragmentation products and IM drift times, dithiol-yne oligomers with distinct architectures were successfully differentiated and characterized. Additionally, experimental collision cross-sections (Ω) derived via IM-MS were compared to theoretically extracted Ω values from molecular dynamics simulated structures to deduce the architectural motif of these comb oligomers. Overall, this work demonstrates the benefits of combining various mass spectrometry techniques in order to gain a complete understanding of a complex polymer mixture. [ABSTRACT FROM AUTHOR]