Electrospray Research Articles

Illustrate the metabolic regulatory mechanism of Taohong Siwu decoction in ischemic stroke by mass spectrometry imaging.

Metabolic dysregulation in the ischemic region has been increasingly recognized as a contributing factor to ischemic stroke pathogenesis. Taohong Siwu decoction (THSWD), a traditional Chinese medicine preparation used to enhance blood circulation, is frequently employed in treating ischemic stroke. However, the metabolic regulatory mechanism underlying the therapeutic effects of THSWD in ischemic stroke remains largely unexplored. In this study, we employed desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to investigate the metabolic changes in the brain tissue of ischemic stroke rat model. Our investigation revealed that 30 metabolites exhibited significant dysregulation in the ischemic brain regions, specifically the cortex and striatum, following ischemic injury. Following the treatment of THSWD, almost all the dysregulated metabolites got different degrees of callback. Further pathway analysis indicated that THSWD might exert its therapeutic effects by restoring energy metabolism, improving neurotransmitter metabolism, recovering polyamine metabolism, and so on. DESI-MSI offers a favorable methodology for investigating the alterations in the spatial distribution and level within the ischemic brain region following treatment with THSWD in ischemic stroke. These findings provide a novel perspective on the underlying mechanisms of the efficacy of THSWD in ischemic stroke treatment.

Synthesis of an Insulated Oligo(phenylene ethynylene) Dimer Through Cyclodextrin-Based [c2]Daisy Chain Rotaxane

Oligo(phenylene ethynylene)s (OPEs) are π-conjugated systems with promising optical, bioactive, and electrical properties, making them valuable candidates for molecular electronics and biosensors. Controlling the arrangement and orientation of π-conjugated systems is crucial in developing molecular devices. Recently, we developed insulated diarylacetylene dimers using a [c2]daisy chain rotaxane strategy, which brings two cores into close proximity without covalent bonding and shields them with permethylated α-cyclodextrins. Here, we synthesized an insulated OPE dimer using a similar rotaxane strategy to investigate its optical properties. The rotaxane structure and optical properties were evaluated using nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization high-resolution mass spectrometry (ESI-HRMS), and absorption and fluorescence spectroscopy. This study is expected to contribute to the development of optical and electronic materials utilizing OPEs.

In vitro antifungal activity of extracts and alkaloid compounds from Piper arboreum against dermatophytes

Piper is widely distributed in subtropical regions and species of this genus are known for their potent pharmacological activities. Piper arboreum Aubl. is a traditional medicinal plant popularly known as "pau-de-angola", "jaborandi", and chili pepper, demonstrating antifungal, trypanocidal, antibacterial, and antioxidant activities. The leaves of P. arboreum were extracted using Soxhlet and dichloromethane to obtain the extract, which was then fractionated using solvents of different polarities. Samples were analyzed using ultra-high-performance liquid chromatography coupled with mass spectrometry equipped with an electrospray ionization source. Antifungal microdilution assays were performed, and scanning and transmission electron microscopy were used to assess the invasion of the pretreated nail. The minimum inhibitory concentration (MIC) values of the extract and a dichloromethane fraction were, respectively, 62.5 μg/ml and 16.0 μg/ml against Trichophyton rubrum, and 125 μg/ml and 62.5 μg/ml, and 500 μg/ml and 500 μg/ml against T. mentagrophytes, and Microsporum gypseum, respectively. No growth was observed on nail fragments exposed to the extract (at concentrations > 64 µg/ml and then inoculated with spore suspension. Transmission electron microscopy revealed strong inhibition of hyphal growth and an irregular growth pattern following treatment with the extract and the dichloromethane fraction. Results demonstrated the antifungal properties of the P. arboreum extract and its dichloromethane fraction against dermatophytes, with the identification of three different alkaloid compounds. The cytotoxicity was specific towards the fungal cells, and morphological and ultrastructural analyses indicated damage to the cell wall and cytoplasmic membrane as the potential mechanism of action. The leaf material used to generate the extract can be taken from the plant without any detrimental effect thus enabling strategies to be implemented for the exploitation of this species.

Simultaneous qualitative and quantitative analysis for evaluating constituents of Atractylodis macrocephalae rhizome by UPLC-QTOF-MS

AbstractAtractylodis macrocephalae rhizome (AMR) belongs to medicine food homology. Its' clinical application of invigorating the spleen-stomach of AMR was applied to various diseases. In this research, a UPLC-QTOF-MS method was developed for qualitative and quantitative analysis of AMR, simultaneously. A Waters Acquity BEH C18 column (2.1 mm × 100 mm, 1.7 μm particle size) was used for separation of AMR multi-components. The column was eluted with a mobile phase of 0.1% formic acid-water and 0.1% formic acid-acetonitrile. Electron spray ionization with positive-ion mode and external standard method was utilized for quantifying the nine analytes in AMR. Constituents of AMR were scanned by UPLC-QTOF-MS and then identified by mass fragments and chromatographic information compared with the published literature and reference standards. Under positive mode, a total of 61 chemical compositions including 16 terpenoids, 8 polyacetylenes, 6 aromatics, 5 flavonoids, 5 coumarins, 5 organic acids, 4 amino acids, 3 fatty acids, 3 aliphatics, 2 steroids, and 2 alkenes, a nucleoside and an aldehyde were identified. Simultaneously, the contents of three amino acids (L-tyrosine, L-phenylalanine, and L-tryptophan), three sesquiterpenoids (atractylenolide Ⅲ, atractylenolide Ⅱ, and atractylenolide Ⅰ), a flavonoid (rutin), an organic acid (ferulic acid), and a pentacyclic triterpenoid (oleanolic acid) were determined in seventeen AMR batches. Amino acids and triterpenoid were quantified for the first time in AMR. The UPLC-QTOF-MS method developed in this article was reliable, practical, and useful for qualitative and quantitative evaluation of AMR multi-components.

LC-ESI-MS and GC-MS Profiling, Chemical Composition, and Cytotoxic Activity of Endophytic Fungus Pleosporales sp. Derived from Artemisia annua

The chemical profiling of ethyl acetate extract of the endophytic fungus Pleosporales sp. using liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) revealed the presence of 12 metabolites of different chemical classes such as steroids, α-pyrones, asterric acid derivatives, and quinones. Additionally, the gas chromatography–mass spectrometry (GC-MS) profiling of the ethyl acetate (EtOAc) and methanol extracts exhibited the presence of fatty acids and their esters, in which methyl palmitate (18.72%, and 25.48%, respectively) and methyl linoleate (11.92% and 23.39%, respectively) were found in both extracts. On the other hand, palmitic acid (12.60%), methyl oleate (26.90%), oleic acid (4.01%) and linoleic acid (3.25%) were present only in methanol extract. Furthermore, ethyl palmitate (12.60%), 13-octadecenoic acid (19.36%), and ethyl linoleate (3.25%) occurred in EtOAc extract. A phytochemical investigation of both extracts led to the isolation of fatty acids such as palmitic acid (18), oleic acid (20), and linoleic acid (21) and their esters including methyl palmitate (13), methyl stearate (22), methyl linoleate (16), methyl 3-hydroxy-5-methylhexanoate (23), and monomethyl azelate (27), in addition to monoacyl derivatives of glycerol such as 3,3-dihydroxypropyl hexadecanoate (24), 2,3-dihydroxypropyl elaidate (25), and 1-linoleoyl-sn-glycerol (26). The structures of the isolated compounds were identified by different spectroscopic analyses including 1H- and 13C-NMR and GC-MS. The EtOAc extract exhibited a cytotoxic effect against MCF-7 and HepG-2 cell lines, with IC50 values of 4.12 ± 0.10 and 10.05 ± 0.05 μg/mL, respectively.

Development of a Desorption Electrospray Ionization-Multiple-Reaction-Monitoring Mass Spectrometry (DESI-MRM) Workflow for Spatially Mapping Oxylipins in Pulmonary Tissue.

Oxylipins are a class of low-abundance lipids formed via oxygenation of fatty acids. These compounds include potent signaling molecules (e.g., octadecanoids, eicosanoids) that can exert essential functions in the pathophysiology of inflammatory diseases including asthma. While some oxylipin signaling cascades have been unraveled using LC-MS/MS-based methods, measurements in homogenate samples do not represent the spatial heterogeneity of lipid metabolism. Mass spectrometry imaging (MSI) directly detects analytes from a surface, which enables spatial mapping of oxylipin biosynthesis and migration within the tissue. MSI has lacked the sensitivity to routinely detect low-abundance oxylipins; however, new multiple-reaction-monitoring (MRM)-based MSI technologies show increased sensitivity. In this study, we developed a workflow to apply desorption electrospray ionization coupled to a triple quadrupole mass spectrometer (DESI-MRM) to spatially map oxylipins in pulmonary tissue. The targeted MSI workflow screened guinea pig lung extracts using LC-MS/MS to filter oxylipin targets based on their detectability by DESI-MRM. A panel of 5 oxylipins was then selected for DESI-MRM imaging derived from arachidonic acid (TXB2, 11-HETE, 12-HETE), linoleic acid (12,13-DiHOME), and α-linolenic acid (16-HOTrE). To parse this new data type, a custom-built R package (quantMSImageR) was developed with functionality to label regions of interest as well as quantify and analyze lipid distributions. The spatial distributions quantified by DESI-MRM were supported by LC-MS/MS analysis, with both indicating that 16-HOTrE and 12-HETE were associated with airways, while 12,13-DiHOME and arachidonic acid were mapped to parenchyma. This study realizes the potential of targeted MSI to routinely map low-abundance oxylipins with high specificity at scale.

Isomer-Specific, Cryogenic Ion Vibrational Spectroscopy Investigation of D2- and N2-Tagged, Protonated Formic Acid Complexes Using Two-Color, IR-IR Photobleaching.

Here we analyze cryogenic ion vibrational spectra of tagged protonated formic acid (PFA) with electronic structure and anharmonic vibrational calculations to establish the isomers generated by electrospray ionization (ESI) followed by buffer gas cooling to ∼25 K. Two isomers are identified (the trans form (E,Z) and the cis form (E,E)) and generated in comparable abundance despite the fact that the calculated E,E structure lies 6.40 kJ mol-1 above the E,Z form. A large (∼60 kJ mol-1) barrier separates them such that the E,E form can be kinetically trapped upon cooling in the ion trap. The anticooperativity between the H-bonds of the OH groups is explored by measuring the shift in the D2-bound OH fundamental when a second D2 is attached. Both isomers are observed in the N2-tagged counterparts, displaying the expected red-shifted OH bands. These results indicate that ESI generates both isomers and both must be considered when analyzing cluster spectra based on the PFA core ion.

Is Native Mass Spectrometry in Ammonium Acetate Really Native? Protein Stability Differences in Biochemically Relevant Salt Solutions.

Ammonium acetate is widely used in native mass spectrometry to provide adequate ionic strength without adducting to protein ions, but different ions can preferentially stabilize or destabilize the native form of proteins in solution. The stability of bovine serum albumin (BSA) was investigated in 50 mM solutions of a variety of salts using electrospray emitters with submicron tips to desalt protein ions. The charge-state distribution of BSA is narrow (+14 to +18) in ammonium acetate (AmmAc), whereas it is much broader (+13 to +42) in solutions containing sodium acetate (NaAc), ammonium chloride (AmmCl), potassium chloride (KCl), and sodium chloride (NaCl). The average charge state and percent of unfolded protein increase in these respective solutions, indicating greater extents of protein destabilization and conformational changes. In contrast, no high charge states of either bovine carbonic anhydrase II or IgG1 were formed in AmmAc or NaCl despite their similar melting temperatures to BSA, indicating that the presence of unfolded BSA in some of these solutions is not an artifact of the electrospray ionization process. The charge states formed from the nonvolatile salt solutions do not change significantly for up to 7 min of electrospray, but higher charging occurs after 10 min, consistent with solution acidification. Formation of unfolded BSA in NaAc but not in AmmAc indicates that the cation identity, not acidification, is responsible for structural differences in these two solutions. Temperature-dependent measurements show both increased charging and aggregation at lower temperatures in NaCl:Tris than in AmmAc, consistent with lower protein stability in the former solution. These results are consistent with the order of these ions in the Hofmeister series and indicate that data on protein stability in AmmAc may not be representative of solutions containing nonvolatile salts that are directly relevant to biology.

IMPACT OF CYP2D6 POLYMORPHISMS IN PREDUCTING OCCURRENCE OF ADVERSE EFFECT TO TAMOXIFEN AND DEVELOPING RECCURENCE IN ER+ BREAST CANCER PATIENETS:

Objectives: Breast cancer is a major public health in Algeria. Tamoxifen has been approved in the treatment of ER+ breast cancer. Some of negative side effects of tamoxifen are frequently a reason for discontinuation of therapy during treatment, which would otherwise be potentially lifesaving. In the current study, we assessed the association between CYP2D6 polymorphisms and tamoxifen efficacy in Algerian population receiving tamoxifen as adjuvant therapy in ER+ breast cancer. Methods: A total of 76 Algerian hormone receptor-positive premenopausal breast cancer patients with adjuvant tamoxifen treatment were investigated (45.36±6.13). DNA genotyping was performed by TaqMan Open Array technology. Tamoxifen and its metabolites levels were measured by ultra-high-performance liquid chromatography (UHPLC) followed by electro spray tandem mass spectrometry (LC-MS/MS). Results: A significant association between the presence of deficit copy of enzyme activity and development of adverse effect after the commencement of tamoxifen therapy. Low plasma endoxifen were observed in patients categorized as (NM/PM), (IM/ IM), (IM/PM) and (PM/PM). Patients with increased plasma endoxifen concentrations were significantly more likely than patients with reduced or null activity to not report recurrences (P<0.05). We realized that the combination genotypes NM/PM, IM/IM, IM/PM, with PM/PM were more strongly associated with disease recurrence and adverse effects than NM carries of CYP2D6*1 allele (P<0.05). Conclusion: Our results affirm that CYP2D6 polymorphism should be considered in predicting the occurrence of adverse effect fatty liver in women treated with tamoxifen. Thus, alternative treatment can be intended and lifestyle modifications can be implemented

A reagent-free, sequence-dependent in situ peptide self-cyclization strategy under physiological condition

Cyclic peptides are an important class of bioactive molecules used as drugs as well as biomolecular probes. Peptide cyclization under the physiological environment, without added chemicals or reagents, would be a highly useful technique for in situ applications. A simple, highly efficient, and green procedure for side-chain to side-chain in situ peptide cyclization is established here at the physiological condition. The methodology further allows the release of small biologically active molecules through peptide self-cyclization. Bioactive molecules, as well as other organic leaving groups (having primary or secondary alcohol as a functional group), were conjugated to a short peptide RXE sequence (X = Pro/Ala/Gly). The peptides were designed to undergo cyclization under physiological conditions and release the covalently attached chemotherapeutic drug and nucleobases, in a controlled manner. In vitro studies were performed in detail, with optimized physiological parameters, to understand the kinetics as well as the mechanism of self-cyclization. The mechanism of action was investigated by HPLC and ESI-Mass spectrometry. The conformational change, due to cyclization of the peptides, was monitored by CD spectroscopy. The present concept of peptide self-cyclization leading to a bond cleavage could be a potential method of delivery of small, bioactive molecules such as chemotherapeutic drugs.

Structural elucidation of 14-membered ring macrolide antibiotics using electrospray ionization tandem mass spectrometry and density functional theory calculations.

Macrolides are critical antibiotics featuring a macrocyclic lactone core with deoxy sugars. Understanding their gas-phase fragmentation is challenging but essential for improving structural elucidation in mass spectrometry, which has implications for drug discovery and development. We used electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS) combined with quantum chemical calculations to investigate the fragmentation pathways of erythromycin A and roxithromycin. This approach helps elucidate the preferred fragmentation routes influenced by protonation sites. Macrolides showed similar fragmentation patterns, including sequential losses of saccharide or amino sugar units and dehydration from the macrocycle core. Multiple competitive pathways were observed, influenced by protonation sites. Computational studies confirmed the most favorable protonation sites and their impact on fragmentation, providing insights into key diagnostic product ions. Subsequent fragments involved rearrangement pathways such as alkene formation and cleavages via remote hydrogen transfers and pericyclic reactions. Our integrated approach offers a comprehensive understanding of macrolide fragmentation, enhancing structural elucidation and potential applications in drug development. This study advances mass spectrometry analysis of macrolides, contributing to pharmaceutical research by integrating orthogonal annotation methods and fragmentation studies.

Crystal structures and photophysical properties of mono- and dinuclear ZnII complexes flanked by triethylammonium

Two new zinc(II) complexes, triethylammonium dichlorido[2-(4-nitrophenyl)-4-phenylquinolin-8-olato]zinc(II), (C6H16N){Zn(C21H13N2O3)Cl2] (ZnOQ), and bis(triethylammonium) {2,2′-[1,4-phenylenebis(nitrilomethylidyne)]diphenolato}bis[dichloridozinc(II)], (C6H16N)2[Zn2(C20H14N2O2)Cl4] (ZnBS), were synthesized and their structures were determined using ESI–MS spectrometry, 1H NMR spectroscopy, and single-crystal X-ray diffraction. The results showed that the ligands 2-(4-nitrophenyl)-4-phenylquinolin-8-ol (HOQ) and N,N′-bis(2-hydroxybenzylidene)benzene-1,4-diamine (H2BS) were deprotonated by triethyl-amine, forming the counter-ion Et3NH+, which interacts via an N—H...O hydrogen bond with the ligand. The ZnII atoms have a distorted trigonal–pyramidal (ZnOQ) and distorted tetrahedral (ZnBS) geometries with a coordination number of four, coordinating with the ligands via N and O atoms. The N atoms coordinating with ZnII correspond to the heterocyclic nitrogen for the HOQ ligand, while for the H2BS ligand, it is the nitrogen of the imine (CH=N). The crystal packing of ZnOQ is characterized by C—H...π interactions, while that of ZnBS by C—H...Cl interactions. The emission spectra showed that ZnBS complex exhibits green fluorescence in the solid state with a small band-gap energy, and the ZnOQ complex does exhibit non-fluorescence.

Plukenetia volubilis leaves as source of anti-Helicobacter pylori agents.

Helicobacter pylori infection is a major issue worldwide, with widespread prevalence, combined with its link to gastritis, peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Meanwhile, effectiveness of current treatment protocols is limited by increasing antibiotic resistance and patient compliance issues due to long regimens and side effects. Plukenetia volubilis, or sacha inchi, is a valuable source of bioactive molecules. However, studies on its antimicrobial activity, especially against H. pylori, are lacking. In this study, the anti-H. pylori activity of P. volubilis leaves water extract was explored using in vitro and in silico approaches. High-Performance Liquid Chromatography coupled to Electrospray Ionisation and Quadrupole Time-of-Flight Mass Spectrometry (HPLC-ESI- QTOF-MS-MS) analysis of the water extract from the leaves was used to characterise the chemical composition of the plant and allowed identification of some flavonoids, such as astragalin, and some phenolic compounds. Then, high-speed counter current chromatography (HSCCC) was used to fractionate the ethyl acetate partition obtained from the water extract from the leaves. The presence of flavonoids derived from kaempferol was confirmed and astragalin was isolated for the first time in P. volubilis. The P. volubilis water infusion, ethyl acetate extract and the isolated astragalin exhibited anti-bacterial activity against H. pylori J99 and two clinical isolates (e.g., minimum inhibitory concentrations of 0.53, 0.51 and 0.49μg/mL, respectively, for clarithromycin-resistant clinical isolate SSR366). Then, using molecular docking for potential protein targets for H. pylori, it was verified that astragalin could interact with these proteins by in silico analysis. These findings highlight that P. volubilis and astragalin produce a bacteriostatic activity against H. pylori and may have potential to be used in treatment against H. pylori, after further research.

An experimental study on distinguishing gel pen ink stains using desorption electrospray ionisation mass spectroscopy combined with the K-means algorithm

Abstract In the realm of document examination, the identification of suspicious alterations to handwritten documents is an important factor in case characterisation. Investigating the differences in gel pen ink compositions has significant implications. In this study, we used desorption electrospray ionisation mass spectrometry (DESI-MS) to analyse the ink compositions of gel pens. The methodology involved the following steps. (1) Sample selection: a total of 227 gel pens available in the market were procured for the study. (2) Pre-experimental parameter exploration: preliminary experiments were performed to optimise the experimental parameters. (3) Analytical technique: DESI-MS was used to collect compositional data from the gel pen ink samples, without requiring pre-treatment of the samples. (4) Data analysis: the obtained data were analysed using the Davies–Bouldin index, Calinski–Harabasz index, and K-means algorithm for ink sample classification. The experimental findings indicated that DESI-MS is a viable method for examining the ink compositions of gel pens. Notably, the testing process is minimally destructive and does not necessitate pre-treatment of the samples. Furthermore, variations in the ink compositions were observed among different models of gel pens within the same brand, and the extent of the variation in the composition varied across brands. Additionally, there were instances in which the ink compositions of different brands of gel pens exhibited similarities.

New Isocoumarins from An Endophytic Fungal Strain Diaporthe arengae M2 and Their Antibacterial Activities.

Four new isocoumarin derivatives 12-O-acetyl-isocitreoisocoumarinol (1), (+)-(10R)-O-acetyl-diaportinol (2-a), (-)-(10S)-O-acetyl-diaportinol (2-b), peyroisocoumarin E (3) and new stereoconfigurations of three isocoumarin derivatives desmethyldichlorodiaportinol A (4), threo-monochlorodiaportinol A (5-a), erytheo-monochlorodiaportinol A (5-b), together with nine known ones (6-14), were separated from the rice fermentation of endophytic fungus Diaporthe arengae M2 isolated from Camellia oleifera. The structures of new compounds were determined by extensive spectroscopic analyses including nuclear magnetic resonance (NMR) and high resolution electrospray ionization mass spectroscopy (HR-ESI-MS). Compounds 4, 7, 8, 12, 13 exhibited definite inhibition against five strains of bacteria with the MIC values range from 16 μg/mL to 64 μg/mL.

An Assessment of Surface Contamination and Dermal Exposure to 5-Fluorouracil in Healthcare Settings by UPLC-MS/MS Using a New Atmospheric Pressure Ionization Source

5-Fluorouracil (5-FU) is a well-known cytostatic drug, which is often used in cancer treatments. Yet, it is also a very dangerous compound for people who are occupationally exposed to it for a long time, such as pharmacy employees, nurses and cleaning staff. We aimed to improve and implement a LC-MS/MS method for 5-FU quantification on surface contamination samples collected with swabs in a pharmacy department and outpatient nursing station of a university hospital. To improve the existing methods to quantify 5-FU, we compared a LC-MS/MS method using the frequently applied electrospray ionization source (ESI) with a UniSpray ionization source (USI). To determine the contamination of 5-FU in a pharmacy department preparing 5-FU infusion bags, which are then given to patients in the outpatient nursing stations, we collected multiple surface swabs of the laminar flow cabinets and frequently touched objects, before the preparation and administration of 5-FU and afterwards. Furthermore, we sampled the protective gloves and the bare hands of employees of the pharmacy department, involved in the preparation of the infusion bags. Using the USI source, we were able to reach the lowest limit of quantification (LOQ). With this technique, we were able to detect 5-FU contamination on the laminar flow cabinets and frequently used objects in the pharmacy department and the outpatient nursing station in the very low ng/cm2 range. This contamination was mostly higher after preparation or administration than before. While we also found 5-FU on the protective gloves, we almost found no 5-FU on the skin of the pharmacy technicians preparing the 5-FU infusion bags. In conclusion, our method was able to detect very low concentrations of 5-FU contamination, but the contamination we found is very unlikely to result in any issues for the personnel working in these areas.

Chemical Fingerprinting of PM2.5 via Sequential Speciation Analysis Using Electrochemical Mass Spectrometry.

Chemical fingerprinting to characterize the occurrence state and abundance of organic and inorganic constituents within fine particulate matter (PM2.5) is useful in evaluating the associated health risks and tracing pollution sources. Herein, an analytical strategy for the rapid analysis of metal and organic constituents in PM2.5 was developed employing a combination of sequential chemical extraction coupled with mass spectrometry detection. H2O, CH3OH, EDTA-2Na, electrochemical oxidation, and electrochemical reduction were sequentially utilized to extract the chemical constituents in PM2.5 samples on a homemade device employing simultaneous online detection using two linear trap quadrupole mass spectrometers (LTQ-MS) with electrospray ionization (ESI) in positive and negative modes. After a single analytical procedure, dozens of metals (e.g., Pb, Cr, and Cu), organic compounds (e.g., amines, polycyclic aromatic hydrocarbons, and aliphatic acids), and negative ions (e.g., NO3-, NO2-, and Cl-) were comprehensively detected in the water-soluble, liposoluble, insoluble, oxidizable, and reducible fractions of PM2.5 samples, and their physical and chemical relationships were established.

Anti-inflammatory Activities and Mechanisms of New Compounds Isolated from the Fruits of Foeniculum vulgare Mill.

Forty-nine compounds, including six previously unknown together with forty-three known ones, were isolated from the fruits of Foeniculum vulgare Mill. Their structures were elucidated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV), nuclear magnetic resonance (NMR), and electronic circular dichroism (ECD) methods. All isolates were evaluated their anti-inflammatory activity. The results indicated that compounds 1, 6, 35 and 45 inhibit lipopolysaccharide(LPS)-induced nitric oxide production in RAW 264.7 macrophages with IC50 values of 17.13 ± 0.74, 14.40 ± 0.54, 112.13 ± 2.08 and 77.02 ± 3.62 μg/mL, respectively. Moreover, the potential targets of the four active ingredients were explored through network pharmacology, revealing that SRC, TP53, AKT1, and PIK3CA may serve as key anti-inflammatory targets. To confirm the potential binding mode, molecular docking was employed, which demonstrated that all active targets except SRC exhibited favorable binding energy with compound 35. Additionally, the anti-inflammatory activities of compounds 1-6 were first observed in this experiment.

Detection of Veterinary Drugs in Food Using a Portable Mass Spectrometer Coupled with Solid-Phase Microextraction Arrow.

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.

A novel quantitative method for the determination of 10B-carrier boronophenylalanine in rat plasma by UHPLC-MS/MS and comparison with ICP-MS

L-Boronophenylalanine (BPA), a widely used 10B carrier for clinical boron neutron capture therapy (BNCT), was quantified in rat plasma through a simple, effective and stable ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. Chromatographic separation was performed on an ACQUITY UPLC HSS T3 (100 mm × 2.1 mm, 1.8 μm) column with the mobile phase of 0.5 % formic acid aqueous solution and acetonitrile. For the detector, the m/z ion pairs used for quantification were 209.1→120.1 for BPA and 210.1→120.1 for internal standard in a positive mode by electrospray ionization (ESI) using multiple reaction monitoring (MRM). The method is specific and robust with rare affection by endogenous substances in the matrix. A good linear relationship was observed over 80–80000 ng/mL (r2 = 0.9993). The values of inter- and intra-day accuracy and precision were within the acceptance criteria of ±15 %. BPA was found to be stable under different experimental conditions. This developed method was successfully applied on a pharmacokinetic experiment on Sprague-Dawley rats (intravenous injection, 125 mg/kg) and a comparation between UHPLC-MS/MS and ICP-MS for BPA was carried out.