Search

The control of movement and orientation of gas-phase molecules has become the focus of many research areas in molecular physics. Here, ND3 molecules are polarized in a segmented, curved electrostatic guide and adiabatically aligned inside a rotatable mass spectrometer (MS). Alignment is probed by photoionization using a linearly polarized laser. Rotation of the polarization at fixed MS orientation has the same effect as the rotation of the MS at fixed polarization, proving that the molecular alignment adiabatically follows the MS axis. Polarization-dependent ion signals reveal state-specific populations and allow for a quantification of the aligned sample in the space-fixed reference frame. [ABSTRACT FROM AUTHOR]

A guided ion beam tandem mass spectrometer was used to study the reactions of U+ with N2 and NO. Reaction cross sections were measured over a wide range of energy for both systems. In each reaction, UN+ is formed by an endothermic process, thereby enabling the direct measurement of the threshold energy and determination of the UN+ bond dissociation energy. For the reaction of U+ + N2, a threshold energy (E0) of 4.02 ± 0.11 eV was measured, leading to D0 (UN+) = 5.73 ± 0.11 eV. The reaction of U+ + NO yields UO+ through an exothermic, barrierless process that proceeds with 94 ± 23% efficiency at the lowest energy. Analysis of the endothermic UN+ cross section in this reaction provides E0 = 0.72 ± 0.11 eV and, therefore, D0 (UN+) = 5.78 ± 0.11 eV. Averaging the values obtained from both reactions, we report D0 (UN+) = 5.76 ± 0.13 eV as our best value (uncertainty of two standard deviations). Combined with precise literature values for the ionization energies of U and UN, we also derive D0 (UN) = 5.86 ± 0.13 eV. Both bond dissociation energies agree well with high-level theoretical treatments in the literature. The formation of UN+ in reaction of U+ with NO also exhibits a considerable increase in reaction probability above ∼3 eV. Theory suggests that this may be consistent with the formation of UN+ in excited quintet spin states, which we hypothesize are dynamically favored because the number of 5f electrons in reactants and products is conserved. [ABSTRACT FROM AUTHOR]

Various charged thorium ions such as singly charged, doubly charged, and triply charged thorium ions trapped in the ion trap can be used to excite the Th-229 first nuclear excited state via the electronic bridge process. We present an integration of a linear ion trap with a time-of-flight mass spectrometer to investigate trapped Th-232 ions. Various charged thorium ions are produced by laser ablation and dynamically loaded into the ion trap. After sufficient collisional cooling, thorium ions are extracted along one of the radial directions for time-of-flight mass spectrometry by rapidly quenching the trapping potential and applying high-voltage extracting pulses. The charge states of thorium ions are identified and the maximum mass resolutions of thorium ions reach ∼100 with initial 300 K collisional cooling. The velocity distributions of ablated various charged thorium ions are measured, and the results agree well with Monte Carlo simulation. Lifetimes of thorium ions are determined to be a few tens of seconds in the ion trap, which are helpful for further spectroscopic studies of Th-229 nuclear transition. [ABSTRACT FROM AUTHOR]

A guided ion beam tandem mass spectrometer was employed to study the reactions of U+ + CO2, UO+ + O2, and the reverse of the former, UO+ + CO. Reaction cross sections as a function of kinetic energy over about a three order of magnitude range were studied for all systems. The reaction of U+ + CO2 proceeds to form UO+ + CO with an efficiency of 118% ± 24% as well as generating UO2+ + C and UCO+ + O. The reaction of UO+ + O2 forms UO2+ in an exothermic, barrierless process and also results in the collision-induced dissociation of UO+ to yield U+. In the UO+ + CO reaction, the formation of UO2+ in an endothermic process is the dominant reaction, but minor products of UCO+ + O and U+ + (O + CO) are also observed. Analysis of the kinetic energy dependences observed provides the bond energies, D0(U+–O) = 7.98 ± 0.22 and 8.05 ± 0.14 eV, D0(U+–CO) = 0.73 ± 0.13 eV, and D0(OU+–O) = 7.56 ± 0.12 eV. The values obtained for D0(U+–O) and D0(OU+–O) agree well with the previously reported literature values. To our knowledge, this is the first experimental measurement of D0(U+–CO). An analysis of the oxide bond energies shows that participation of 5f orbitals leads to a substantial increase in the thermodynamic stability of UO2+ relative to ThO2+ and especially transition metal dioxide cations. [ABSTRACT FROM AUTHOR]

In the mirabegron (MIR) synthesis, the N‐nitroso mirabegron (NNM) is obtained during synthetic process of MIR; water is being used in reaction under acidic condition. Nitrite source is from water, and secondary amine source is from MIR as it has secondary amine; NNM is generated as an impurity during the synthesis of MIR. The presence of NNM in MIR could potentially affect its effectiveness. The purpose of this study was to establish a Ultra‐performance liquid chromatography‐mass spectrometry/mass spectrometry (UPLC‐MS/MS) methodology to identify NNM in MIR samples. The method for NNM analysis was developed on Acquity HSS T3 (100*2.1) mm 1.8 μm column with gradient elution using mobile phase consisted of 0.1% formic acid in water (mobile phase A) and 0.1% formic acid in methanol (mobile phase B). Mass spectrometer with electrospray ionization operated in the MRM mode was used in the analysis of NNM (m/ z 426.20 → 170.00). The UPLC‐MS/MS methodology proposed showed a good linearity (0.02 to 0.72 ppm), good system precision (RSD = 0.57%), good method precision (RSD = 0.87%), acceptable accuracy (94.5–116.5%), low detection limit (0.006 ppm) and low quantification limit (0.02 ppm) for NNM. The UPLC‐MS/MS methodology proposed can be utilized to assess the quality of MIR sample for the presence of NNM impurity. [ABSTRACT FROM AUTHOR]

Rationale: Elastin‐like polypeptides (ELPs) are elastic and thermoresponsive biopolymers composed of VPGXG repeats (X can be any amino acid except proline), used in biomedical applications, for example, tissue engineering and drug delivery. As different variants of ELP are mostly produced fermentatively, there is a need for the development of analysis methods that allow for absolute protein quantification in both complex matrices and purified samples and MW determination of the final products. Methods: ELPs were intracellularly expressed in Escherichia coli quantified after cell lysis and enzymatic digestion using a proline‐specific protease ProAlanase (Promega) at acidic conditions. Resulting peptides were separated by liquid chromatography, and mass spectrometry analysis was conducted by electrospray ionization high‐resolution mass spectrometry using an Orbitrap mass spectrometer. The addition of a stable isotopically labeled internal standard enabled quantification in complex matrices. Prior to intact mass analysis, ELPs were purified from fermentation broth by inverse temperature cycling. Intact protein analysis was performed using reversed‐phase liquid chromatography, and mass spectrometry analysis was conducted by electrospray ionization high‐resolution mass spectrometry using a time‐of‐flight mass spectrometer. Results: Absolute quantification of ELPs was achieved by utilizing ELP‐specific properties, that is, proline‐rich, soluble at low pH and low temperature. The repetitive nature of ELPs allows for sensitivity increase and use of higher dilution factors to minimize the matrix effects. Despite the lack of amino acids with charged side chains (Arg, His, Lys, Asp, and Glu) in ELP, we demonstrated successful intact protein analysis using reversed‐phase LC coupled to electrospray ionization TOF MS. Moreover, truncated protein forms could be chromatographically separated and characterized as well as N‐terminal modifications. Conclusions: Both methods combined enabled quantitative and qualitative characterization of fermentatively produced ELPs. [ABSTRACT FROM AUTHOR]

We report a micro-fractionation device for high performance liquid chromatography-mass spectrometry to archive chromatographic separations on an array of optimized surface energy traps (SETs). The method has the potential to significantly alter nanoflow LC-MS workflow, decoupling separation and analysis. The wetting characteristics of the SETs cause the HPLC eluent stream to spontaneously split into droplet microfractions. The droplet mirofractions are then dried down to enable facile storage and transport of the archived separation. Discontinuously dewetting array parameters were explored to maximize array volume and resolution using a combination of SET design, shape, size, and spacing. Mass spectrometry analysis is performed utilizing a liquid micro-junction surface sampling probe to extract dried analytes from the surface of the SETs followed by electrospray ionisation. A reverse phase separation of pharmaceutical compounds is "recorded" using the micro-fractionation device followed by "reading" the chromatographic trace with a mass spectrometer 24 hours after the separation was performed/archived, demonstrating a true decoupling of LC, and MS. Additionally, we demonstrate the ability to collect microfractions with sub-one-second integration time, approaching the scan time of a mass spectrometer or UV-Vis detector. With further improvements to the device, sub-1-second micro-fractionation may enable seamless reconstruction of archived chromatograms indistinguishable from online LC-MS data, while also providing the benefits of easy storage and transport of archived separations. [ABSTRACT FROM AUTHOR]

Activation, break‐in, and/or pre‐treatment protocols are generally applied to energy conversion devices before regular operation to reach stable performance. There remains much to understand about the relationships among physical properties, performance, and electrochemical pre‐treatments. Here, a design‐of‐experiments (DoE) strategy is employed to address this gap by demonstrating the influence of five pre‐treatment parameters for carbon‐supported Pt‐nanoparticle catalysts on the electrocatalytic oxygen reduction reaction (ORR). A subset of pre‐treatments, developed using a central composite design, are tested in a flow cell combined with an inductively‐coupled plasma mass spectrometer (on‐line ICP‐MS). The DoE‐based approach facilitates comprehensive insights from two orders of magnitude fewer experiments than a conventional grid search. The coupled on‐line ICP‐MS setup enables effective catalysis and real‐time catalyst dissolution data. Leveraging insights from DoE for on‐line ICP‐MS and additional characterization, a model is built between the degradation of a multi‐dimensional supported Pt surface, its performance, and applied electrochemical parameters. These investigations identify surface modifications, such as oxidation, and subsequent restructuring of Pt during pre‐treatment as a primary cause of performance deterioration during ORR. By combining DoE with advanced characterization techniques, a powerful approach is demonstrated to gain a mechanistic understanding of pre‐treatment protocols that can be broadly adapted to various reaction chemistries. [ABSTRACT FROM AUTHOR]

Background: Dietary assessment is usually performed through imprecise tools, leading to error-prone associations between diet and health-related outcomes. Metabolomics has been applied in recent years to develop biomarkers of food intake (BFIs) and to study metabolites in the diet-microbiome crosstalk. Candidate BFIs exist to detect intake of meat and to a lesser extent dairy, but validation and further development of BFIs are needed. Here, we aim to identify biomarkers that differentiate between intakes of red meat and dairy, to validate previously reported BFIs for these foods, and to explore the effect of protein-matched meals on selected microbial metabolites. Methods: We conducted a randomized, controlled, cross-over single-meal study comparing a meal with highly fermented yogurt and cheese, and a meal with beef and pork meatballs. Postprandial urine samples from 17 subjects were collected sequentially after each meal up to 24 h and analyzed by untargeted metabolomics through ultra-high-performance-liquid chromatography (UHPLC) coupled via electrospray (ESI) source to a qTOF mass spectrometer. Univariate (repeated measures ANOVA) and multivariate (PLSDA, ML-PLSDA) data analyses were used to select BFIs differentiating the two meals. 3-Indoxyl sulfate, p-cresol sulfate, and several other microbial amino acid catabolites were additionally explored within the urine profiles. Results: Thirty-eight markers of meat and dairy intake were selected and are presented along with their excretion kinetics. Carnosine, taurine, and creatine, as well as hydroxyproline-based dipeptides are confirmed as meat BFIs. For dairy, previously reported metabolites such as acyl-glycines are confirmed, while proline-based dipeptides are reported as novel putative BFIs. Microbial metabolites showed only marginal evidence of differential formation after the two meals. Conclusion: This study allowed us to validate the postprandial kinetics of previously suggested biomarkers of meat and dairy intake and to identify new potential biomarkers. The excretion kinetics are useful to ensure that the collection of urine covers the correct time window in future dietary studies. The BFIs add to the existing body of biomarkers and may further be used in combination to provide a more reliable assessment of meat and dairy intake. Proteolytic microbial metabolites should be further investigated to assess the effect of different protein sources on health. [ABSTRACT FROM AUTHOR]

Collision cross section (CCS) of organic compounds can be measured via Fourier transform‐based mass spectrometry (MS) by modeling the decay rate of transient signals in the analyzer. Deriving CCS values of low‐mass molecules (mass < 2000 Da and CCS < 500 Å2) with Orbitrap MS is challenging due to their high axial frequencies and small absolute variances in cross‐sectional profiles. Here, we acquired mass spectra of progressively more complex low‐mass analytes using commercial Orbitrap mass spectrometers. The transient signals were processed using Fast Fourier transform (FFT) and short‐time Fourier transform (StFFT) to derive decay constants of multiple select ionic species from a single MS full‐scan experiment. Decay constants were translated into CCS values using at least two internal standards in the same mass spectrum. Our results suggest target ionic species should have high S/N in order to derive CCS values with ≤0.5% uncertainty. Limitations in the precision of CCS measurements reflect local space charge effects that disturb ion motion in the analyzer. The derived CCS values of polymer like fragments of Ultramark 1621 and small molecules such as individual protonated amino acids can achieve average ±1% error with selection of internal standards across a wide mass range. Future studies need to optimize the strategy to select internal standards in order to improve the precision and accuracy of CCS measurements for small molecules via Orbitrap MS. [ABSTRACT FROM AUTHOR]

Rational: Nickel is one of humans' most prevalent triggers of allergic contact dermatitis. However, the underlying mechanisms of this allergy still need to be fully understood. One aspect that has yet to be explored is the direct impact of common metal allergens on the skin's metabolites and lipids composition. Method: Our study employed matrix‐assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to analyze spatially resolved metabolic alterations induced by nickel exposure. Cross‐sections of ex vivo porcine ear skin exposed to increasing nickel (II) ion concentrations (17–167 μg/cm2) were measured with an AP‐SMALDI5 AF ion source coupled to Q Exactive HF Orbitrap mass spectrometer. Additionally, the penetration of nickel ions into the skin was observed through its pink complexation with dimethylglyoxime under light microscopy. Results: For nickel ion concentrations up to 84 μg/cm2, most nickel ions were stopped within the stratum corneum, while only a very small proportion of nickel ions penetrated the viable epidermis and dermis. Stratum corneum locations with high nickel ion concentrations showed a decrease in arginine and ceramides. Furthermore, several phosphatidylcholine and sphingomyelin species were found to be downregulated in the viable epidermis and dermis due to the nickel exposure. Conclusion: Nickel penetrates at a trace level into the viable skin and induces severe metabolomic and lipidomic changes in the stratum corneum, epidermis, and dermis, indicating a change in the skin (barrier) function. These findings contribute to a deeper understanding of nickel‐induced skin allergies and provide a solid foundation for further research. [ABSTRACT FROM AUTHOR]

Background: It is presently considered that Corynebacterium especially Corynebacterium kroppenstedtii (CK) infection, is one of the important causes of granulomatous lobular mastitis (GLM). However, the pathogen of mastitis in the past two years has been identified as a newly discovered Corynebacterium. But it is unclear whether the pathogen associated with the occurrence of GLM is also this bacterium. Methods: GLM female patients with positive bacterial culture in pus specimens from February 2023 to February 2024 who were identified as CK infection by mass spectrometer were selected as the research objects in this study, and the clinical isolates were identified by 16S rDNA sequencing technology to identify the specific pathogen of GLM-related bacterial infection. Subsequently, the clinical characteristics of the patients were compared with those of GLM patients without bacterial infection during the same period, to explore the effect of this particular type of Corynebacterium infection on disease development in GLM patients. Finally, we tested the minimum inhibitory concentration (MIC) values of antibiotics when inhibiting these separation strains in vitro through the E-Test experiment, to evaluate their medicine sensitivity. Results: A total of 31 GLM patients initially diagnosed with Corynebacterium kroppenstedtii (CK) infection via MALDI-TOF MS were enrolled in the study. However, subsequent 16S rDNA sequencing revealed that 28 isolates (90.32%) were actually identified as the newly recognized Corynebacterium parakroppenstedtii (CPK). This discovery challenges the conventional belief that CK is the primary pathogen of GLM, suggesting instead that CPK is the predominant pathogen associated with GLM bacterial infections. Comparative analysis of the clinical characteristics between the two groups revealed a significantly higher recurrence rate among CPK-infected GLM patients compared to those without CPK infection, along with elevated prolactin levels (P < 0.05). The sensitivity test results indicated high sensitivity of the isolates to vancomycin, linezolid, and rifampicin. Conclusion: In conclusion, this study highlights that Corynebacterium kroppenstedtii strains isolated from GLM specimens were Corynebacterium parakroppenstedtii, serving as the primary pathogen closely linked to GLM's occurrence. CPK infection significantly increases the risk of recurrence in GLM patients, with elevated prolactin levels potentially playing a pivotal role in this process. In clinical antimicrobial treatment, antimicrobials other than penicillin and ciprofloxacin may be empirically administered when sensitivity test results are inconclusive. [ABSTRACT FROM AUTHOR]

Skin barrier impairment is becoming increasingly common due to changes in lifestyle and modern living environments. Oily sensitive skin (OSS) is a condition that is characterized by an impaired skin barrier. Thus, examining the differences between OSS and healthy skin will enable a more objective evaluation of the characteristics of OSS and facilitate investigations of potential treatments. Initially, a self-assessment questionnaire was used to identify patients with OSS. Biophysical measurements and LAST scores were used to determine whether skin barrier function was impaired. Epidermal biophysical properties, including skin hydration, transepidermal water loss (TEWL), sebum content, erythema index (EI), and a* value, were measured with noninvasive instruments. We subsequently devised a noninvasive D-square sampling technique to identify changes in the skin metabolome in conjunction with an untargeted metabolomics analysis with an Orbitrap Q ExactiveTM series mass spectrometer. In the stratum corneum of 47 subjects, 516 skin metabolites were identified. In subjects with OSS, there was an increase in the abundance of 15 metabolites and a decrease in the abundance of 48 metabolites. The participants with OSS were found to have the greatest disruptions in sphingolipid and amino acid metabolism. The results revealed that an impaired skin barrier is present in patients with OSS and offers a molecular target for screening for skin barrier damage. [ABSTRACT FROM AUTHOR]

A possibility of studying effects of the main background ions formed by the main elements of inductively coupled plasma (H, N, O, and Ar) at the working parameters of the normal ("hot") plasma mode by thermodynamic modeling is assessed. Such ions, responsible for the strongest spectral interferences in the mass spectra are always observed upon the injection of aqueous ("wet") sample solutions into inductively coupled plasma mass spectrometers (ICP MS). The quantitative composition of the main background ions in an ICP MS is calculated as a function of plasma temperature in the temperature range from 3000 to 8000 K using thermodynamic modeling. The results of modeling were compared with the experimental data on the measured mass spectra of the main background ions and a high degree of correlation between the theoretical and experimental results was shown. The agreement between the results of calculations the experimental data validates the thermodynamic model of thermochemical processes in an ICP MS used and its applicability to subsequent calculations in fulfilling analytical tasks. A possibility of the unambiguous assessment of gas-kinetic plasma temperature is confirmed by comparing the theoretical and experimental mass spectra of the main ICP background ions in a normal mode. It was found that the calculated and experimental data on the concentration of only NO+ ions do not agree with the regularities noticed for the other background ions in the normal ICP mode. [ABSTRACT FROM AUTHOR]

Aim Methods Results Conclusions Vitamin D is an essential micronutrient for multiple physiological processes, and its deficiency remains a world‐wide public health problem that cannot be ignored. Dried blood spot (DBS) is a convenient tool in large‐scale epidemiological studies, but its application in evaluating vitamin D status in Chinese population is still scarce. Herein, we aimed to determine the vitamin D status in Chinese pre‐school children using DBS coupled with LC‐MS/MS method.We first developed a sensitive and reliable method for the determination of 25‐hydroxyvitamin D (25(OH)D) in DBS samples using an ultra‐high‐performance liquid chromatograph coupled with triple quadrupole mass spectrometer (UHPLC‐QQQ‐MS/MS). Next, we conducted a pilot study to compare the 25(OH)D concentration in DBS and serum samples. Finally, the assay method was used to evaluate vitamin D status in Chinese pre‐school children.The present method was validated to be reliable and robust for the determination of 25(OH)D in DBS samples. Comparable consistency was observed between the 25(OH)D concentration in DBS and serum samples. A total of 3826 DBS samples collected from children aged 1–7 years were determined. The median concentration of 25(OH)D was 19.57 ng/mL (interquartile range 14.73–24.36 ng/mL), and decreased from 1 to 7 years of age. In addition, 13.51% of male children and 15.12% female children are found to be deficient in 25(OH)D.DBS coupled with LC‐MS/MS is a feasible strategy to evaluate vitamin D status in epidemiological studies. And vitamin D deficiency remains a common health problem in Chinese pre‐school children. [ABSTRACT FROM AUTHOR]

By taking advantage of recent analytical advances, we herein develop the 226Ra/230Th isotope systematics as a novel tool for quantifying nitrate and dissolved silicate fluxes across the sediment–water interface of the deep-ocean floor. Sediment cores were retrieved from the seabed between 4927 m and 5951 m in the North Pacific Ocean. Downcore profiles of 230Th and both dissolved and total 226Ra were measured using a high-sensitivity inductively coupled plasma mass spectrometer. At all study sites, a marked deficit of total 226Ra with respect to 230Th was observed between 0 and 20 cm, indicating active migration of soluble 226Ra from the sediment into the overlying seawater. By constructing the mass balance of 226Ra in the sediment column, the flux of dissolved 226Ra across the sediment–water interface was estimated to range from 461 to 1320 dpm m−2 yr−1. When coupled to a diffusive transport model as developed by early investigators, these flux values of 226Ra enabled us to calculate the flux of any dissolved constituent of interest by measuring their bottom water concentrations and pore water "saturation" concentrations. Based on the 226Ra/230Th disequilibrium approach, the derived fluxes vary between 4.1 and 10.5 mmol m−2 yr−1 for nitrate and between 11 and 49 mmol m−2 yr−1 for dissolved silicate. A compilation of nitrate and silicate fluxes from the seabed in the deep Pacific Ocean shows that these values are consistent with historical flux measurements based on the conventional core incubation method in the same study region. In addition, both nitrate and silicate fluxes exhibit a clear depth-dependent trend. Overall, our results suggest that sedimentary diagenetic alterations at the North Pacific Ocean floor below ∼ 5000 m are efficient so that only < 2 % of the particulate organic carbon and < 12 % of the biogenic opal raining to the seafloor are ultimately preserved in the sediment. [ABSTRACT FROM AUTHOR]

Rationale: Stable isotope analysis of bone provides insight into animal foraging and allows for ecological reconstructions over time, however pre‐treatment is required to isolate collagen. Pre‐treatments typically consist of demineralization to remove inorganic components and/or lipid extraction to remove fats, but these protocols can differentially affect stable carbon (δ13C) and nitrogen (δ15N) isotope values depending on the chemicals, tissues, and/or species involved. Species‐specific methodologies create a standard for comparability across studies and enhance understanding of collagen isolation from modern cetacean bone. Methods: Elemental analyzers coupled to isotope ratio mass spectrometers were used to measure the δ13C and δ15N values of powdered killer whale (Orcinus orca) bone that was intact (control) or subjected to one of three experimental conditions: demineralized, lipid‐extracted, and both demineralized and lipid‐extracted. Additionally, C:N ratios were evaluated as a proxy for collagen purity. Lastly, correlations were examined between control C:N ratios vs. historical age and control C:N ratios vs. sample characteristics. Results: No significant differences in the δ15N values were observed for any of the experimental protocols. However, the δ13C values were significantly increased by all three experimental protocols: demineralization, lipid extraction, and both treatments combined. The most influential protocol was both demineralization and lipid extraction. Measures of the C:N ratios were also significantly lowered by demineralization and both treatments combined, indicating the material was closer to pure collagen after the treatments. Collagen purity as indicated via C:N ratio was not correlated with historical age nor sample characteristics. Conclusions: If only the δ15N values from killer whale bone are of interest for analysis, no pre‐treatment seems necessary. If the δ13C values are of interest, samples should be both demineralized and lipid‐extracted. As historical age and specimen characteristics are not correlated with sample contamination, all samples can be treated equally. [ABSTRACT FROM AUTHOR]

A portable mass spectrometer (PMS) was combined with a mesoporous silica material (SBA-15) coated solid-phase microextraction (SPME) Arrow to develop a rapid, easy-to-operate and sensitive method for detecting five veterinary drugs—amantadine, thiabendazole, sulfamethazine, clenbuterol, and ractopamine—in milk and chicken samples. Equipped with a pulsed direct current electrospray ionization source and a hyperboloid linear ion trap, the PMS can simultaneously detect all five analytes in approximately 30 s using a one-microliter sample. Unlike traditional large-scale instruments, this method shows great potential for on-site detection with no need for chromatographic pre-separation and minimal sample preparation. The SBA-15-SPME Arrow, fabricated via electrospinning, demonstrated superior extraction efficiency compared to commercially available SPME Arrows. Optimization of the coating preparation conditions and SPME procedures was conducted to enhance the extraction efficiency of the SBA-15-SPME Arrow. The extraction and desorption processes were optimized to require only 15 and 30 min, respectively. The SBA-15-SPME Arrow–PMS method showed high precision and sensitivity, with detection limits and quantitation limits of 2.8–9.3 µg kg−1 and 10–28 µg kg−1, respectively, in milk. The LOD and LOQ ranged from 3.5 to 11.7 µg kg−1 and 12 to 35 µg kg−1, respectively, in chicken. The method sensitivity meets the requirements of domestic and international regulations. This method was successfully applied to detect the five analytes in milk and chicken samples, with recoveries ranging from 85% to 116%. This approach represents a significant advancement in food safety by facilitating rapid, in-field monitoring of veterinary drug residues. [ABSTRACT FROM AUTHOR]

One of the still-debated topics regarding the olfactory function concerns the presence or absence of sex-related differences in individuals. In this study, we checked for a relationship between the olfactory function of females and males and their ability to perceive single molecules, and researched how this can influence the intensity with which the complex odor formed by a set of single molecules is perceived. First, females and males were classified as normosmic or hyposmic based on the TDI olfactory score obtained using the Sniffin' Sticks test. Subsequently, the headspace of roasted coffee beans, as a complex olfactory stimulus, was broken down into single molecules by means of a chromatographic column; these were simultaneously conveyed to a mass spectrometer (for their subsequent classification) and to the human nose, which acts as a chemical sensor by means of an olfactometer port. The results obtained with this gas chromatography–olfactometry approach show both qualitative and quantitative differences between females and males, with females performing better than males. In addition, the odor intensity reported by females when sniffing pen #10, containing coffee aroma, is significantly higher than that reported by males. In conclusion, these data highlight that the human ability to perceive both single compounds and complex odors is strongly conditioned, not only by the olfactory function of individuals, but also by their sex. [ABSTRACT FROM AUTHOR]

Background: Dietary assessment is usually performed through imprecise tools, leading to error-prone associations between diet and health-related outcomes. Metabolomics has been applied in recent years to develop biomarkers of food intake (BFIs) and to study metabolites in the diet-microbiome crosstalk. Candidate BFIs exist to detect intake of meat and to a lesser extent dairy, but validation and further development of BFIs are needed. Here, we aim to identify biomarkers that differentiate between intakes of red meat and dairy, to validate previously reported BFIs for these foods, and to explore the effect of proteinmatched meals on selected microbial metabolites. Methods: We conducted a randomized, controlled, cross-over single-meal study comparing a meal with highly fermented yogurt and cheese, and a meal with beef and pork meatballs. Postprandial urine samples from 17 subjects were collected sequentially after each meal up to 24 h and analyzed by untargeted metabolomics through ultra-high-performance-liquid chromatography (UHPLC) coupled via electrospray (ESI) source to a qTOF mass spectrometer. Univariate (repeated measures ANOVA) and multivariate (PLSDA, ML-PLSDA) data analyses were used to select BFIs differentiating the two meals. 3-Indoxyl sulfate, p-cresol sulfate, and several other microbial amino acid catabolites were additionally explored within the urine profiles. Results: Thirty-eight markers of meat and dairy intake were selected and are presented along with their excretion kinetics. Carnosine, taurine, and creatine, as well as hydroxyproline-based dipeptides are confirmed as meat BFIs. For dairy, previously reported metabolites such as acyl-glycines are confirmed, while proline-based dipeptides are reported as novel putative BFIs. Microbial metabolites showed only marginal evidence of differential formation after the two meals. Conclusion: This study allowed us to validate the postprandial kinetics of previously suggested biomarkers of meat and dairy intake and to identify new potential biomarkers. The excretion kinetics are useful to ensure that the collection of urine covers the correct time window in future dietary studies. The BFIs add to the existing body of biomarkers and may further be used in combination to provide a more reliable assessment of meat and dairy intake. Proteolytic microbial metabolites should be further investigated to assess the effect of different protein sources on health. [ABSTRACT FROM AUTHOR]

The retina plays a crucial role in processing and decoding visual information, both in normal development and during myopia progression. Recent advancements have introduced a library-independent approach for data-independent acquisition (DIA) analyses. This study demonstrates deep proteome identification and quantification in individual mice retinas during myopia development, with an average of 6,263 ± 86 unique protein groups. We anticipate that the use of a predicted retinal-specific spectral library combined with the robust quantification achieved within this dataset will contribute to a better understanding of the proteome complexity. Furthermore, a comprehensive mice retinal-specific spectral library was generated, encompassing a total identification of 9,401 protein groups, 70,041 peptides, 95,339 precursors, and 761,868 transitions acquired using SWATH-MS acquisition on a ZenoTOF 7600 mass spectrometer. This dataset surpasses the spectral library generated through high-pH reversed-phase fractionation by data-dependent acquisition (DDA). The data is available via ProteomeXchange with the identifier PXD046983. It will also serve as an indispensable reference for investigations in myopia research and other retinal or neurological diseases. [ABSTRACT FROM AUTHOR]

In this article, a brief review of the development of the Knudsen effusion mass spectrometric (KEMS) approach in the Theoretical Metallurgy Department of the KTH Royal Institute of Technology and in the in the Laboratory of Metallurgy of the Helsinki University of Technology and modifications of quadrupole model QMG420 mass spectrometers, is presented. The thermodynamic data obtained from vaporization of standards, such as NaCl, CsCl, B2O3, and Ag, and of the B2O3–Al2O3 and ZnO–P2O5 systems is compared with the data obtained using a magnetic MS1301 mass spectrometer. For the first time, composition of the vapor phase over the Dy2O3–DyF3, CaO–CaCl2, and Cu–Mg systems and the partial pressures of components at high temperatures are investigated. The experimental data obtained for the investigated systems are used for prediction of the vaporization processes and modeling of thermodynamic properties and high‐temperature phase equilibria in the multicomponent systems used in metallurgy. An account is given of the detailed studies of the vaporization processes and thermodynamic properties of some multicomponent systems composed of oxides, fluorides, and carbonates forming mold powders for continuous casting of steel. Some new directions of the ongoing studies by the KEMS method are summarized. [ABSTRACT FROM AUTHOR]

This study reports the development of an effective high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the quantification of two analogs of rosmarinic acid (RA) in rat plasma, namely methyl (E)-2-(3-(3,4-difluorophenyl)acrylamido)-3-(3,4-dihydroxyphenyl)propanoate (A11) and methyl (E)-3-(3,4-dihydroxyphenyl)-2-(3-(3,4-dihydroxyphenyl)acrylamido)propanoate (A2). These analogs, featuring N atoms instead of O atoms, exhibit enhanced bioavailability and distinct pharmacological activities compared with RA. The HPLC separation was carried out on a C18 column (1.9 μm, 2.1 mm × 100 mm) coupled with a security guard C18 column (5 μm, 2.1 mm × 10 mm). A triple-quadrupole mass spectrometer equipped with an electrospray ionization ion source was utilized for ion generation. Pseudoephedrine hydrochloride was utilized as a standard, and a single-step protein precipitation method using isopropanol:ethyl acetate (v/v, 20:80) was employed for sample pretreatment. The developed method demonstrated excellent linearity over the concentration range of 5–750 ng/ml for both A11 and A2, with relative standard deviations of <15% and relative errors within 15% during daily course analysis. The method allowed for the unambiguous quantification and identification of A11 and A2 in vivo. The results of this study provide a meaningful foundation for evaluating the clinical applications of these analogs. [ABSTRACT FROM AUTHOR]

Background: 1,3,4-thiadiazole nucleus is a flexible nucleus. There are numerous biological activities showed by this nucleus. Anticancer, anthelmintic, antimicrobial, anti-inflammatory, antioxidant; anti-HIV, anti- tubercular and anti-carbonic anhydrase are a few activities showed by 1,3,4-thiadiazole derivatives. This project study aimed to investigate the anthelmintic and in silico anticancer activity of derivatives of 1,3,4-thiadiazole. Materials and Methods: The UV visible spectrophotometer (Shimadzu UV-1900) has been used to determine λmax of the synthesized molecules. The FT-IR (Bruker Alpha-II) spectrometer was used for IR spectra (4000-400 cm-1) via the KBr disc method. Proton (1H) and Carbon-13 (13C) NMR spectra were recorded in CDCl3 or (D6) DMSO at 300-500 MHz and 101-125 MHz, respectively, using the Bruker AV-III 400 spectrometer (Germany). High-Resolution Mass Spectra (HRMS) were obtained using the Xevo G2-XS QT of Mass Spectrometer (USA) with positive ESI mode at 70 eV. Results: The bonding energy for compounds 1, 2 and 3 were all in the range -42.929 to -48.909 kcal/mol. Results of the docking study shows interactions of compound 3 with the neighboring residues and showing significant anticancer activity. The presence of o-nitro, m-nitro and p-hydroxy groups makes compounds 1 (105.77%), 2 (131.67%) and 3 (155.54%) more potent and nearly equal in terms of inhibition percentage when compared to standard ascorbic acid. Compound-1 [5-([1,1'-biphenyl]-4-yl)- N -(2-nitrobenzylidene)- 1,3,4-thiadiazol-2-amine] showed significant anthelmintic activity. Conclusion: The biological profiles of these new generations of thiadiazoles would represent a fruitful matrix for further development of better medicinal agents. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to combine proteomics and metabolomics to evaluate the immune system of short‐track speed skaters (STSS) before and after a training course. Our research focused on changes in urinary proteins and metabolites that have the potential to serve as indicators for training load. Methods: Urine samples were collected from 21 elite STSS (13 male and 8 female) of the China National Team before and immediately after one training course. First‐beat sports sensor was used to monitor the training load. Proteomic detection was performed using a Thermo UltiMate 3000 ultra high performence chromatography nano liquid chromatograph and an Orbitrap Exploris 480 mass spectrometer. MSstats (R package) was used for the statistical evaluation of significant differences in proteins from the samples. Two filtration criteria (fold change [FC] > 2 and p < 0.05) were used to identify the differential expressed proteins. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis for differential proteins was performed to identify the pathways involved. Nontargeted metabolomic detection was performed using ultra performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS_) with an ACQUITY 2D UPLC plus Q Exactive (QE) hybrid Quadrupole‐Orbitrap mass spectrometer. Differential metabolites were identified using non‐parametric statistical methods (Wilcox's rank test). Two filtration criteria (FC > 1.2 and p < 0.05) were used to identify differential metabolites. Combined analysis of proteomic and metabolomics were performed on the "Wu Kong" platform. Correlation analysis was performed using Spearman's rank correlation coefficient. Results: (1) The most upregulated proteins were immune‐related proteins, including complement proteins (C9, C4–B, and C9) and immunoglobulins (IgA, IgM, and IgG). The most downregulated proteins were osteopontin (OPN) and CD44 in urine. The correlation analysis showed that the content of OPN and CD44 (the receptor for OPN) in urine were significantly negatively correlated with the upregulated immune‐related proteins. The content of OPN and CD44 is sex‐dependent and negatively correlated with the training load. (2) The most upregulated metabolites included lactate, cortisol, inosine, glutamine, argininosuccinate (the precursor for arginine synthesis), 3‐methyl‐2‐oxobutyrate (the catabolite of valine), 3‐methyl‐2‐oxovalerate (the catabolite of isoleucine), and 4‐methyl‐2‐oxopentanoate (the catabolite of leucine), which is sex‐dependent and negatively correlated with OPN and CD44. (3) The joint analysis revealed five main related pathways, including the immune and innate immune systems. The enriched immune‐related proteins included complements, immunoglobulins, and protein catabolism‐related proteins. The enriched immune‐related metabolites included cAMP, N‐acetylgalactosamine, and glutamate. (4) There is a significant negative correlation between the content of OPN and CD44 in urine and the training load. Conclusion: One training course can lead to the activation of the immune system and a sex‐dependent decrease in the content of OPN and CD44. Training load has a significant and negative correlation with the content of OPN and CD44, suggesting that OPN and CD44 could be potential indicators for training load. [ABSTRACT FROM AUTHOR]

Background: The high global prevalence of prediabetes requires its early identification. Amino acids (AAs) have emerged as potential predictors of prediabetes. This study investigates the association between amino acids and prediabetes in the Kazakh population. Materials and Methods: In this case-control study, serum AAs levels were measured using the Trace GC 1310 gas chromatography system coupled with the TSQ 8000 triple quadrupole mass spectrometer (Thermo Scientific, Austin, TX, USA) followed by silylation with the BSTFA + 1% TMCS derivatization method. Biochemical parameters, including total cholesterol, HDL-C, LDL-C, triglycerides, fasting glucose, HbA1c, and Creatinine, were assessed for each participant. Trained professionals conducted anthropometric and physical examinations (which included taking blood pressure and heart rate measurements) and family history collection. Results: A total of 112 Kazakh individuals with prediabetes and 55 without prediabetes, aged 36–65 years, were included in the study. Only Alanine and valine showed a significant association with prediabetes risk among the 13 AAs analyzed. Our findings revealed an inverse relationship between Alanine and Valine and prediabetes in individuals of Kazakh ethnicity. Conclusion: A lower serum level of Alanine and Valine may serve as a predictive biomarker for prediabetes in the Kazakh population. [ABSTRACT FROM AUTHOR]

Background/Objectives: This study aimed to develop a fully validated HPLC-MS/MS method for quantifying total and unbound lenalidomide concentrations in human plasma. Methods: Unbound concentrations were measured using plasma ultrafiltrate prepared with Amicon® Centrifugal Filters. Lenalidomide and lenalidomide-d5 (internal standard) were extracted from 50 μL of human plasma using liquid–liquid extraction. Chromatography was conducted with a Halo® C18 column using 0.1% formic acid and methanol (20:80, v/v) as the mobile phase. The mass spectrometer was operated in a positive ion mode with an electrospray ionization interface and multiple reaction monitoring modes. Results: Calibration curves were linear over the range of 5 to 1000 ng/mL (r2 > 0.996) for both the total and unbound lenalidomide. For total lenalidomide concentrations, between-run precision (coefficients of variation) and accuracy were 1.70–7.65% and 94.45–101.10%, respectively. For unbound concentrations, inter-day precision and accuracy were 1.98–10.55% and 93.95–98.48%, respectively. Conclusions: We developed a highly reproducible, sensitive, and efficient bioanalytical method using a smaller volume of plasma sample (50 μL) with a relatively short run time (2.5 min). The proposed analytical method was successfully applied to measure total and unbound lenalidomide concentrations at various time points in multiple myeloma patients with renal impairment. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) and volatile inorganic compounds (VICs) provide critical information across many scientific fields including atmospheric chemistry and soil and biological processes. Chemical ionization (CI) mass spectrometry has become a powerful tool for tracking these chemically complex and temporally variable compounds in a variety of laboratory and field environments. It is particularly powerful with time-of-flight mass spectrometers, which can measure hundreds of compounds in a fraction of a second and have enabled entirely new branches of VOC and/or VIC research in atmospheric and biological chemistry. To accurately describe each step of these chemical, physical, and biological processes, measurements across the entire range of gaseous products is crucial. Recently, chemically comprehensive gas-phase measurements have been performed using many CI mass spectrometers deployed in parallel, each utilizing a different ionization method to cover a broad range of compounds. Here we introduce the recently developed Vocus AIM (adduct ionization mechanism) ion–molecule reactor (IMR), which samples trace vapors in air and ionizes them via chemical ionization at medium pressures. The Vocus AIM supports the use of many different reagent ions of positive and negative polarity and is largely independent of changes in the sample humidity. Within the present study, we present the performance and explore the capabilities of the Vocus AIM using various chemical ionization schemes, including chloride (Cl -), bromide (Br -), iodide (I -), nitrate (NO 3-), benzene cations (C6H6+), acetone dimers ((C 3 H 6 O) 2 H +), and ammonium (NH 4+) reagent ions, primarily in laboratory and flow tube experiments. We report the technical characteristics and operational principles, and compare its performance in terms of time response, humidity dependence, and sensitivity to that of previous chemical ionization approaches. This work demonstrates the benefits of the Vocus AIM reactor, which provides a versatile platform to characterize VOCs and VICs in real time at trace concentrations. [ABSTRACT FROM AUTHOR]

Magnetic particle spray mass spectrometry (MPS-MS), an innovative ambient ionization technique proposed by our research group, was employed to determine beta-blockers in human plasma samples. A dispersive solid phase extraction of atenolol, metoprolol, labetalol, propranolol, nadolol, and pindolol was carried out using magnetic molecularly imprinted polymer (M-MIP) particles that were attached to the tip of a metal probe, which was placed in the mass spectrometer inlet. A solvent (1% formic acid in methanol) was dispensed on the particles, and the Taylor cone was formed around them (in high voltage). The analytes were desorbed/ionized and determined by a triple quadrupole mass spectrometer. M-MIP was synthesized with oxprenolol as a pseudo-template, demonstrating good selectivity to beta-blockers compared with no-analog molecules, with an adsorption process occurring in monolayers, according to isotherm studies. Kinetic experiments indicated chemisorption as the predominant M-MIP/analyte interaction. The analytical curves were linear (R2 > 0.98), and the limit of quantification was 3 µg L−1 for all the analytes. Limits of detection ranged from 0.64 to 2.41 µg L−1. Precisions (relative standard deviation) and accuracies (relative error) ranged from 3.95 to 21.20% and -17.05 to 18.93%, respectively. MPS-MS proved to be a simple, sensitive, and advantageous technique compared with conventional approaches. The analyses were fast, requiring no chromatographic separation and without ionic suppression. The method is aligned with green chemistry principles, requiring minimal sample, solvent, and sorbent amounts. MPS-MS successfully integrates sample preparation and ambient ionization mass spectrometry and holds great potential for application with other sorbents, samples, and analytes. [ABSTRACT FROM AUTHOR]

Therapeutic drug monitoring (TDM) may be beneficial for cyclin-dependent kinase 4/6 inhibitors (CDK4/6is), such as palbociclib, ribociclib, and abemaciclib, due to established exposure–toxicity relationships and the potential for monitoring treatment adherence. Developing a method for quantifying CDK4/6is, abemaciclib metabolites (M2, M20), and letrozole in dried blood spots (DBS) could be useful to enhance the feasibility of TDM. Thus, an optimized LC-MS/MS method was developed using the HemaXis DB10 device for volumetric (10 µL) DBS collection. Chromatographic separation was achieved using a reversed-phase XBridge BEH C18 column. Detection was performed with a triple quadrupole mass spectrometer, utilizing ESI source switching between negative and positive ionization modes and multiple reaction monitoring acquisition. Analytical validation followed FDA, EMA, and IATDMCT guidelines, demonstrating high selectivity, adequate sensitivity (LLOQ S/N ≥ 30), and linearity (r ≥ 0.997). Accuracy and precision met acceptance criteria (between-run: accuracy 95–106%, CV ≤ 10.6%). Haematocrit independence was confirmed (22–55%),with high recovery rates (81–93%) and minimal matrix effects (ME 0.9–1.1%). The stability of analytes under home-sampling conditions was also verified. Clinical validation supports DBS-based TDM as feasible, with conversion models developed for estimating plasma concentrations (the reference for TDM target values) of letrozole, abemaciclib, and its metabolites. Preliminary data for palbociclib and ribociclib are also presented. [ABSTRACT FROM AUTHOR]

To analyze groundwater contamination with uranium, groundwater samples were collected from the major industrial area of Jalandhar, Punjab, India (as the industrial effluent is found to contain a large number of heavy metals) and analyzed using ICPMS (Inductively Coupled Plasma Mass Spectrometer) for uranium-238. Uranium-238 concentrations in groundwater ranged from 4.96 µg/L and 38.52 µg/L, with an average of 17.0 µg/L. All the values of uranium concentration and uranium activity concentration in the samples were found within the permissible range by the World Health Organization (WHO). The hazard quotient for all the samples is found to be below one, indicating very low or no risk to the population. [ABSTRACT FROM AUTHOR]

This study employs a high‐dimensional consensus mass spectral (HDCMS) similarity scoring technique to discriminate isomers collected using an electron ionization mass spectrometer. The HDCMS method was previously introduced and applied to the discrimination of mass spectra of constitutional isomers, methamphetamine and phentermine, collected with direct analysis real‐time mass spectrometry (DART‐MS). The method formulates the problem of discriminating mass spectra in a mathematical Hilbert space and is hence called "high dimensional." It requires replicate mass spectra to build a Gaussian model and evaluate the inner products between these functions. The resulting measurement variability is used as a signature by which to discriminate spectra. In this work, HDCMS is tested on electron impact ionization (EI) mass spectra of 7 terpene and terpene‐related (C10H16 and C10H14) isomers with experimental retention indices that differ by less than 30 and with traditional cosine similarity scores greater than 0.9, on a scale of 0 to 1, when compared with at least one other compound in the test set. Using identical instrument parameters, 15 replicate gas chromatography–electron ionization–mass spectrometry (GC‐EI‐MS) spectra of each isomer were collected and separated into distinct library and query sets. The HDCMS algorithm discriminated each isomer, indicating the method's potential. Because the method requires replicate measurements, observations from a simple heuristic study of the number of replicates required to discriminate these isomers is presented. The paper concludes with a discussion of compound discrimination using HDCMS and the benefits and drawbacks of applying the method to EI‐MS data. [ABSTRACT FROM AUTHOR]

Background: Dairy cow milking practices require cleaning and disinfection of the teat skin before and after milking to ensure the safety and quality of milk and prevent intramammary infections. Antimicrobial proteins of natural origin can be valuable alternatives to traditional disinfectants. In a recent field trial, we demonstrated that a teat dip based on a nisin A-producing Lactococcus cremoris (L) had comparable efficacy to conventional iodophor dip (C) in preventing dairy cow mastitis. Here, we present the differential shotgun proteomics investigation of the milk collected during the trial. Methods: Four groups of quarter milk samples with low (LSCC) and high somatic cell count (HSCC) collected at the beginning (T0) and end (TF) of the trial were analyzed for a total of 28 LSCC (14 LSCC T0 and 14 LSCC TF) and 12 HSCC (6 HSCC T0 and 6 HSCC TF) samples. Milk proteins were digested into peptides, separated by nanoHPLC, and analyzed by tandem mass spectrometry (LC-MS/MS) on an Orbitrap Fusion Tribrid mass spectrometer. The proteins were identified with MaxQuant and interaction networks of the differential proteins were investigated with STRING. The proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD045030. Results: In healthy milk (LSCC), we detected 90 and 80 differential proteins at T0 and TF, respectively. At TF, the Lactococcus group showed higher levels of antimicrobial proteins. In mastitis milk (HSCC), we detected 88 and 106 differential proteins at T0 and TF, respectively. In the Lactococcus group, 14 proteins with antimicrobial and immune defense functions were enriched at TF vs. 4 proteins at T0. Cathelicidins were among the most relevant enriched proteins. Western immunoblotting validation confirmed the differential abundance. Conclusions: At T0, the proteomic differences observed in healthy milk of the two groups were most likely dependent on physiological variation. On the other hand, antimicrobial and immune defense functions were higher in the milk of cows with mammary gland inflammation of the Lactococcus-treated group. Among other factors, the immunostimulatory action of nisin A might be considered as a contributor. [ABSTRACT FROM AUTHOR]

Uncovering the nature of dark matter microscopic particles is one of the most important disciplinary goals of physics and astronomy in the 21st century, and how to reduce background signals and environmental interference in dark matter experiments is one of the key factors to improve the sensitivity of the detector and to take the lead in obtaining significant detection results. High-purity nitrogen, as a crucial gas for detector purging, scintillator purification and pipe cleaning, among other things, contains the radioactive gases 85Kr and 81Kr in natural Kr, which emit β-rays that can interfere with the detection of dark matter signals. Therefore, it is necessary to measure the concentration of ultra-trace level Kr in high-purity nitrogen, and screen high-purity nitrogen complying with the standard for use in dark matter experiments. This study develops a novel analytical method to determine ultra-trace level Kr in highpurity nitrogen using a static noble gas mass spectrometer coupled with a newly designed sample processing system. A large amount of reactive gases from the original sample are removed by the largevolume high-temperature purification device, and then we explore a simple and iterative trapping method for Ar-Kr separation. This method improves the noble gas separation factor with the promise of ensuring recovery. The separated Kr is fed into a static vacuum mass spectrometer. The detection limit of this method for natural Kr is as low as 10-14 L L-1 with an uncertainty of about 8%. [ABSTRACT FROM AUTHOR]

Theoretical studies of the diffusional isotope effect in solids are still stuck in the 1960s and 1970s. With the development of high spatial resolution mass spectrometers, isotopic data of mineral grains are rapidly accumulated. To dig up information from these data, molecular-level theoretical models are urgently needed. Based on the microscopic definition of the diffusion coefficient (D), a new theoretical framework for calculating the diffusional isotope effect (DIE(v)) (in terms of D*/D) for vacancy-mediated impurity diffusion in solids is provided based on statistical mechanics formalism. The newly derived equation shows that the DIE(v) can be easily calculated as long as the vibration frequencies of isotope-substituted solids are obtained. The calculated DIE(v) values of 199Au/195Au and 60Co/57Co during diffusion in Cu and Au metals are all within 1% of errors compared to the experimental data, which shows that this theoretical model is reasonable and precise. [ABSTRACT FROM AUTHOR]

We conducted a comparative study on chemical composition of organic aerosols (OA) collected in urban and marine atmosphere, respectively, using three mass spectrometers, Filter Inlet for Gases and Aerosol-Iodide-Chemical Ionization Mass Spectrometry (FIGAERO-I-CIMS), Electrospray Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR MS), and Two-dimensional Gas Chromatograph-Electron Ionization-Mass Spectrometry (GC × GC-EI-ToF-MS). The FIGAERO-I-CIMS, ESI(–)-FT-ICR MS, and ESI(+)-FT-ICR MS showed preferred sensitivity to CHO, CHOS/CHONS, and CHON compounds, respectively. The compounds detected by the FIGAERO-I-CIMS were more oxidized and saturated than those detected by the ESI-FT-ICR MS. The GC × GC-EI-ToF-MS offered the advantage of detecting organonitrates, carbonyls, alkanes, oxy-PAHs, and amides in OA. Despite different MS technologies, some distinct features of organic compound distribution were observed between urban and marine OA. CHON compounds were more abundant in urban aerosols than marine aerosols. Organonitrates dominated over reduced-nitrogen organic compounds in all samples, and the relative importance of aromatic and aliphatic nitrates depended on MS technologies and sample type. The contribution of CHOS/CHONS compounds was high (25.1%–66.2%) in urban aerosols or marine aerosols being heavily influenced by continental sources. The most important CHOS/CHONS type in these samples were organosulfates of biogenic origin (49.4%–62.9%). Aromatics-like organosulfates contributed the least (9.1%–21.2%) to total intensity of CHOS/CHONS compounds. Considering high proportion (34.4%–62.8%) of aromatics-like compounds in OA, our result indicated that aromatic compounds were less prone to form organosulfates than aliphatic compounds. More Chlorine-containing compounds were found in clean urban atmosphere than polluted urban atmosphere. Most of Chlorine-containing compounds in urban aerosols were aliphatic, while those in marine aerosols were mostly aromatic. This study demonstrated the necessity of employing multiple MS technologies for a better characterization of chemical composition of complex organic aerosols. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

The minor and trace element compositions of biogenic carbonates such as foraminifera are important tools in paleoceanography research. However, most studies have focused primarily on samples with element to calcium (El/Ca) ratios higher than the El/Ca range often found in benthic foraminifera. Here, we systematically assess the precision and accuracy of foraminifera elemental analysis across a wide range of El/Ca especially at relatively low ratios, using a method on a Thermo Scientific iCAP Qc quadrupole Inductively Coupled Plasma Mass Spectrometer (ICP‐MS). We focus on two benthic foraminifera species, Hoeglundina elegans and Cibicidoides pachyderma, and prepared a suite of solution standards based on their typical El/Ca ranges to correct for signal drift and matrix effects during ICP‐MS analysis and to determine analytical precision. We observe comparable precisions with published studies at high El/Ca, and higher relative standard deviations for each element at lower El/Ca, as expected from counting statistics. The overall long‐term analytical precision (2σ) of the H. elegans‐like consistency standard solutions was 6.5%, 4.6%, 5.0%, for Li/Ca, Mg/Ca, Mg/Li, and 6.4%, 10.0%, 4.2% for B/Ca, Cd/Ca, Sr/Ca. The precision for H. elegans‐like Mg/Li is equivalent to a temperature uncertainty of 0.5–1.1°C. Measurement precisions were also assessed based on three international standards (one solution and two powder standards) and replicate measurements of H. elegans and C. pachyderma samples. We provide file templates and program scripts that can be used to design calibration and consistency standards, prepare run sequences, and convert the raw ICP‐MS data into molar ratios. Key Points: Higher relative standard deviations are reported at lower element/calcium values, as expected from counting statisticsConsistency standards having similar ratios to the unknown samples provide an accurate estimate of errorsFor the Hoeglundina elegans Mg/Li—temperature proxy, analytical precision (2σ) is equivalent to a temperature uncertainty of 0.5–1.1°C [ABSTRACT FROM AUTHOR]

Understanding sedimentary deposits in wetlands is crucial for their effective management. In this study, we used an integrated approach to estimate the radiocarbon (14C) chronology, sedimentation rate, and nutrient dynamics of the Khushalsar wetland in the Kashmir Himalaya. A UWITEC gravity corer was used to retrieve a 60 cm sediment core from the wetland. Accelerator mass spectrometer (AMS) facilitated 14C dating of core sediments revealed that the age of the sediments ranged from 248 ± 30 BP at 15–16 cm depth to 889 ± 27 BP at 59–60 cm depth. The linear increase in 14C age with depth revealed steady depositional conditions. According to the Constant Rate of Supply model applied to 14C ages, the sedimentation rate for Khushalsar wetland averaged 0.10 cm per year over the past 829 years, spanning from 1189 to 2018. Physicochemical analysis revealed a high concentration of ionic components in the sediments, wherein the electrical conductivity (EC) ranged from 2230 to 2970 µS cm−1, and organic matter (OM) ranged from 6.6 to 19.8%. The regression model demonstrated significant (p < 0.05) positive and negative associations between the physicochemical parameters. EC explained 91% of the variation in total dissolved solids (TDS) and 89% of the variation in salinity, whereas organic carbon (OC) explained 44% of the variation in nitrogen and 20% of the variation in phosphorus. Depth exhibited a strong positive association with C/N ratio (explaining 17% of the variation) and a negative association with OC, nitrogen, and phosphorus (explaining 59%, 56%, and 50% of the variation, respectively). The study concluded that primary productivity, stormwater runoff, anthropogenic inputs (domestic sewage, raw fecal matter, slaughterhouse wastes), and deforestation in the catchment area are responsible for the increased nutrient concentration and high sedimentation rate in the wetland. [ABSTRACT FROM AUTHOR]

Introduction: Mango fruit and its by-products represent a very diverse and abundant source of sugars and components with anti-inflammatory and antioxidant properties, such as dietary fiber, vitamins, and polyphenols. Consuming mango pulp might reduce health disorders caused by inflammatory and oxidative processes such as obesity related diseases. Mango and its by-products contain compounds that can either promote or neutralize inflammatory and oxidative environments; variations in their composition may directly influence the degree of bioactivity. This work aimed to analyze the nutritional and nutraceutical profiles presented in the three different mango by-products to know their possible nutraceutical potential. Objective: This work aimed to analyze the nutritional and nutraceutical profiles presented in the three different mango by-products to know their possible nutraceutical potential. Methods: Ripe Ataulfo mango products (pulp, peel, and peel fiber) were evaluated for nutritional composition by AOAC methods. β-carotene and ascorbic acid were analyzed by UV-Vis liquid chromatography (LC), while mangiferin, phenolics and flavonoids by LC coupled to mass spectrometer detector. The antioxidant capacity was correlated to each of the bioactive compounds. Results: Ripe Ataulfo mango products (pulp, peel, and peel fiber) were evaluated for nutritional, antioxidant, and phytochemical characteristics. All the by-products demonstrated significant differences (P ≤ 0.05) in nutritional and chemical composition. Mango peel had the highest β-carotene, vitamin C, and mangiferin values. Mango pulp had the highest values for free sugars (73 g 100 g-1), but low phytochemicals values, contrasting the peel fiber with 81% of total dietary fiber but minimum values of free sugars and β-carotene and no vitamin C. The highest antioxidant capacity was presented for mango peel. Results obtained from this study indicate that the mango Ataulfo pulp and by-products are divergent and represent a good source of bioactive compounds. Conclusions: Mango peel composition is a natural combination of high concentrations of mangiferin, flavonoids, phenolic acids, vitamin C, provitamin A, and dietary fiber, all involved with inflammation and cell oxidative stress-related disease control and prevention. However, mango peel exhibited the most significant nutraceutical potential due to its high antioxidant capacity. [ABSTRACT FROM AUTHOR]

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal 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.)

Ammonia and amines play critical roles in secondary aerosol formation, especially in urban environments. However, fast measurements of ammonia and amines in the atmosphere are very scarce. We measured ammonia and amines with a chemical ionization mass spectrometer (CIMS) at the urban center in Houston, Texas, the fourth most populated urban site in the United States, during October 2022. Ammonia concentrations were on average four parts per billion by volume (ppbv), while the concentration of an individual amine ranged from several parts per trillion by volume (pptv) to hundreds of pptv. These reduced nitrogen compounds were more abundant during weekdays than on weekends and correlated with measured CO concentrations, implying they were mostly emitted from pollutant sources. Both ammonia and amines showed a distinct diurnal cycle, with higher concentrations in the warmer afternoon, indicating dominant gas-to-particle conversion processes taking place with the changing ambient temperatures. Studies have shown that dimethylamine is critical for new particle formation (NPF) in the polluted boundary layer, but currently there are no amine emission inventories in global climate models (as opposed to ammonia). Our observations made in the very polluted area of Houston, as well as a less polluted site (Kent, Ohio) from our previous study (You et al., 2014), indicate there is a consistent ratio of dimethylamine over ammonia at these two sites. Thus, our observations can provide a relatively constrained proxy of dimethylamine using 0.1 % ammonia concentrations at polluted sites in the United States to model NPF processes. [ABSTRACT FROM AUTHOR]

The detection and quantification of polar pesticides in liquid chromatography coupled with mass spectrometry present significant analytical challenges. This study compares the performance of three LC columns (Hypercarb™, Raptor Polar X™, and Anionic Polar Pesticide™) in separating and quantifying eleven polar pesticides in chicken eggs using a score-based methodology. Analytes include glyphosate, its metabolites, and other high-polarity pesticides like Ethephon, Glufosinate, and Fosetyl aluminum, included in the EU's official control plan. Polar pesticides, characterized by high polarity and hydrophilicity, lead to analytical issues such as poor retention and unconventional peak shapes with traditional reversed-phase methods. Their weak interaction with hydrophobic stationary phases complicates separation, necessitating specific stationary phases to enhance retention and selectivity. This study evaluates these columns' efficacy in complex matrices like chicken eggs and other food samples. Chromatographic separation was performed using a UPLC system coupled with a Q-TOF mass spectrometer; extraction and purification involved freeze-out, centrifugation, and filtration steps. The study highlights the critical role of column selection in achieving accurate and reliable separation and quantification of highly polar analytes in matrices of animal origin, offering in the meantime an easy-to-apply methodology of selection for the right determination of the best chromatographic column for different purposes. [ABSTRACT FROM AUTHOR]

Backgrounds: Coronavirus disease 2019 (COVID-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The high mortality and morbidity rate and its course with a wide variety of clinical symptoms indicate that the disease affects many metabolic pathways. The aim of our study was to investigate the metabolic effects of SARS-CoV-2 by evaluating the urinary organic acid profile in patients with SARSCoV- 2 infection. Can metabolites in urine guide the diagnosis, follow-up, treatment, and prognosis of COVID-19? Methods: Forty-two patients, including 30 SARS-CoV-2 RT-PCR positive patients and 12 SARS-CoV-2 RT-PCR negative controls, were studied. SARS-COV-2 RT-PCR of nasopharyngeal swab samples was studied. Urines were evaluated in the GCMS-QP2010 SE Gas Chromatograph Mass Spectrometer (SHIMADZU) device for organic acid profile in the metabolism laboratory. Urine organic acid profile was evaluated by studying 117 organic acids in each patient. Results: Tiglylglycine, 2-hydroxybutyric acid, 4-hydroxyphenylpyruvic acid, 3-hydroxypropionic acid, erythro- 4,5-dihydroxyhexanoic acid lactone, 2-hydroxyphenylacetic acid, N-acetyltyrosine, 3-phenyllactic acid, 5-hydroxyindolacetic acid, 3-hydroxysebacic acid, palmitic acid, 3-methylglutaconic acid, 3-methylglutaric acid, lactic acid, pyruvic acid-oxime, 3-hydroxysobutyric acid, and organic acids were found to be increased, compared to the control group. Conclusions: Tiglylglycine has been specifically identified as a potential biomarker of respiratory chain disorders. The deterioration in lipid metabolism and pyruvate pathway in COVID-19 patients was evaluated as remarkable. [ABSTRACT FROM AUTHOR]

Peroxidase is a biotechnologically important enzyme. The purification of peroxidase from the root of Citrullus colocynthis was carried out in a simple two-step process with maximum purity level. The sample was extracted in a high salt buffer, and the enzyme was partially purified with a Q-Sepharose anion exchange column. Final purification was carried out with HighLoad 16/600 Superdex G-75 column. The purified protein was analysed with SDS gel electrophoresis, which suggested a single band of approximately 35 kDa. Further, the enzyme was identified with the help of Mass spectrometric analysis using an ESI-QTOF Mass spectrometer. The study will be helpful for the isolation and its commercial uses in biotechnology. [ABSTRACT FROM AUTHOR]

Context. Carbonyl sulfide (OCS) is widely observed in the gas phase toward star-forming regions and was the first of the only two sulfur-bearing species to be detected in interstellar ices so far. However, the chemical network governing its formation is still not fully understood. While the sulfurization of CO and the oxidation of CS are often invoked to form OCS, other mechanisms could have a significant contribution. In particular, the multistep reaction involving CO and SH is a good candidate for forming a significant portion of the OCS in dense cloud environments. Aims. We aim to constrain the viability of the CO + SH route for forming solid OCS in the interstellar medium, in a similar manner as CO + OH is known to produce CO2 ice. This is achieved by conducting a systematic laboratory investigation of the targeted reactions on interstellar ice analogs under dense cloud conditions. Methods. We used an ultrahigh vacuum chamber to simultaneously deposit CO, H2S, and atomic H at 10 K. SH radicals produced in situ via hydrogen abstraction from H2S reacted with CO to form OCS. We monitored the ice composition during deposition and subsequent warm-up by means of Fourier-transform reflection absorption infrared spectroscopy (RAIRS). Complementarily, desorbed species were recorded with a quadrupole mass spectrometer (QMS) during temperature-programmed desorption (TPD) experiments. Control experiments were performed to secure the product identification. We also explored the effect of different H2S:CO mixing ratios – with decreasing H2S concentrations – on the OCS formation yield. Results. OCS is efficiently formed through surface reactions involving CO, H2S, and H atoms. The suggested underlying mechanism behind OCS formation is CO + SH → HSCO, followed by HSCO + H → OCS + H2. The OCS yield reduces slowly, but remains significant with increasing CO:H2S mixing ratios (CO:H2S = 1:1, 5:1, 10:1, and 20:1). Conclusions. Our experiments provide unambiguous evidence that OCS can be formed from CO + SH in the presence of H atoms. This route remains efficient for large H2S dilutions (5% with respect to CO), suggesting that it is a viable mechanism in interstellar ices. Given that SH radicals can be created in clouds over a wide evolutionary timescale, this mechanism could make a non-negligible contribution to the formation of interstellar OCS ice. [ABSTRACT FROM AUTHOR]

Background: Nocardiosis, despite its rarity and underreporting, is significant due to its severe impact, characterized by high morbidity and mortality rates. The development of a precise, reliable, rapid, and straightforward technique for identifying the pathogenic agent in clinical specimens is crucial to reduce fatality rates and facilitate timely antimicrobial treatment. In this study, we aimed to identify Nocardia spp. in clinical isolates, using MALDI-TOF MS as the primary method, with molecular methods as the gold standard. Clinical Nocardia isolates were identified using 16S rRNA/hsp65/gyrB/secA1/rpoB gene sequencing. Identification performance of the Bruker MALDI Biotyper 3.1 (V09.0.0.0_8468) and MBT Compass 4.1 (V11.0.0.0_10833) for Nocardia identification was evaluated. Results: Seventy-six Nocardia isolates were classified into 12 species through gene sequencing. The MALDI Biotyper 3.1 (V09.0.0.0_8468) achieved 100% genus-level accuracy and 84.2% species accuracy (64/76). The MBT Compass 4.1 with the BDAL Database (V11.0.0.0_10833) improved species identification to 98.7% (75/76). The updated database enhanced species level identification with scores > 1.7, increasing from 77.6% (59/76) to 94.7% (72/76), a significant improvement (P = 0.001). The new and simplified extraction increased the proportion of strains identified to the species level with scores > 1.7 from 62.0% (18/29) to 86.2% (25/29) (P = 0.016). An in-house library construction ensured accurate species identification for all isolates. Conclusions: The Bruker mass spectrometer can accurately identify Nocardia species, albeit with some variations observed between different database versions. The MALDI Biotyper 3.1 (V09.0.0.0_8468) has limitations in identifying Nocardia brasiliensis, with some strains only identifiable to the genus level. MBT Compass 4.1 (V11.0.0.0_10833) effectively addresses this shortfall, improving species identification accuracy to 98.7%, and offering quick and reliable identification of Nocardia. Both database versions incorrectly identified the clinically less common Nocardia sputorum as Nocardia araoensis. For laboratories that have not upgraded their databases and are unable to achieve satisfactory identification results for Nocardia, employing the new and simplified extraction method can provide a degree of improvement in identification outcomes. [ABSTRACT FROM AUTHOR]

Supporting bee populations is essential considering threats posed by human activities like pesticide usage and habitat destruction. However, the current methods for monitoring and analyzing beehives and their surrounding environments are invasive, complex, and time-consuming. These methods often rely heavily on laboratory analyses, making them difficult to implement independently in the field. This study explores the application of portable membrane inlet mass spectrometer (MIMS) for noninvasive hive analysis, demonstrating its ability to detect various compounds indicative of hive conditions and environmental stressors. In addition to the expected compounds found in beehives, such as α-bergamotene, hexadecanoic acid, heptadecane, hexadecanamide, α-bisabolol-, 9-octadecenamide, (Z) − , and benzaldehyde, unexpected compounds, pollutants, like indane (polycyclic aromatic hydrocarbon) and carbofuran (pesticide), were also detected. The MIMS detection method provides rapid, accurate, and real-time results, making it suitable for preventive measures against bee diseases and integral to environmental biomonitoring. This integration of technology represents a significant advancement in bee conservation efforts, offering hope for the future of both bees and ecosystems. [ABSTRACT FROM AUTHOR]

A highly accurate, precise, and simple liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for ketotifen (KTF) estimation from Beagle dog plasma was developed and validated, with ketotifen-d3 (KTF-d3) as the internal standard (IS). KTF and IS were detected on an API 4000 mass spectrometer in multiple reaction monitoring (MRM) mode in electrospray ionization (ESI) positive ionization mode. The transitions were monitored at m/z 310.2 → 96.0 for KTF and m/z 313.2 → 99.1 for IS. KTF and IS were extracted from plasma using liquid-liquid extraction with methyl tertiary-butyl ether and then analyzed for 3 min with extracted samples (7 µL) into the LC–MS/MS system. Analytes were separated on a Luna® Hilic column (50 × 2.0 mm i.d., 3 μm) using the Nexera X2 HPLC. The mobile phase A consisted of 10 mmol/L ammonium formate (pH 3.0), while mobile phase B consisted of 0.05% formic acid in acetonitrile. The ratio of mobile phase was 5:95 (v/v) at a flow rate of 0.2 mL/min. The method has been thoroughly validated in accordance with the bioanalytical method validation guidelines established by the Ministry of Food and Drug Safety in Korea and the U.S. Food and Drug Administration, addressing selectivity, lower limit of quantification, linearity, carryover, precision, accuracy, recovery, matrix effect, and stability. The developed LC–MS/MS method was effectively utilized for the bioequivalence assessment of ketotifen in Beagle dog plasma following the oral administration of ketotifen syrup. [ABSTRACT FROM AUTHOR]

The common octopus (Octopus vulgaris) is an excellent candidate for aquaculture diversification, due to its biological traits and high market demand. To ensure a high-quality product while maintaining welfare in captive environments, it is crucial to develop non-invasive methods for testing health biomarkers. Proteins found in skin mucus offer a non-invasive approach to monitoring octopus welfare. This study compares the protein profiles in the skin mucus of wild, aquarium-maintained, and senescent specimens to identify welfare biomarkers. A tandem mass tag (TMT) coupled with an Orbitrap Eclipse Tribrid mass spectrometer was used to create a reference dataset from octopus skin mucus, identifying 1496 non-redundant protein groups. Although similar profiles were observed, differences in relative abundances led to the identification of potential biomarkers, including caspase-3-like, protocadherin 4, deleted in malignant brain tumors, thioredoxin, papilin, annexin, cofilin and mucin-4 proteins. Some of these proteins also revealed potential as bioactive peptides. This investigation provides the most extensive analysis of the skin mucus proteome in the common octopus and is the first to explore how aquarium maintenance and senescence alter the mucus proteome. This research highlights the potential of skin mucus protein/peptides as non-invasive monitoring biomarkers in cultured animals. [ABSTRACT FROM AUTHOR]

Rationale: The Δ36S standard deviation measured in a conventional isotope ratio mass spectrometer such as MAT 253 is ca 0.1‰ to 0.3‰. At this precision, it is difficult to resolve the origin of non‐mass‐dependent sulfur isotope fractionation in tropospheric sulfate aerosol and in Martian meteorites or small deviations from the canonical mass‐dependent fractionation laws. Interfering ions with m/z at 131 of 36SF5+ are suggested by the community as the cause of the poor precision, but the exact ion species has not been identified or confirmed. Methods: Here we examined the potential interfering ions by using a Thermo Scientific ultrahigh‐resolution isotope ratio mass spectrometer to measure SF6 working gas and SF6 gases converted from IAEA‐S1/2/3 Ag2S reference materials. Results: We found that there are two resolvable peaks to the right of the 36SF5+ peak when a new filament was installed, which are 186WF42+ followed by 12C3F5+. However, only the 12C3F5+ interference peak was observed after more than three days of filament use. 12C3F5+ is generated inside the instrument during the ionization process. Avoiding the interfering signals, we were able to achieve a Δ36S standard deviation of 0.046‰ (n = 8) for SF6 zero‐enrichment and 0.069‰ (n = 8) for overall measurement start from silver sulfide IAEA‐S1. Conclusions: Aging the filament with SF6 gas can avoid the interference of 186WF42+. Minimizing the presence of carbon‐bearing compounds and avoiding the interfering signals of 12C3F5+ from 36SF5+, we can improve Δ36S measurement accuracy and precision, which helps to open new territories for research using quadruple sulfur isotope composition. [ABSTRACT FROM AUTHOR]