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Pheophytin a and chlorophyll a have been investigated by electrospray mass spectrometry in the positive and negative modes, in view of the importance of the knowledge of their properties in photosynthesis. Pheophytin and chlorophyll are both observed intensely in the protonated mode, and their main fragmentation route is the loss of their phytyl chain. Pheophytin is observed intact in the negative mode, while under collisions, it is primarily cleaved beyond the phytyl chain and loses the attaching propionate group. Chlorophyll is not detected in normal conditions in the negative mode, but addition of methanol solvent molecule is detected. Fragmentation of this adduct primarily forms a product (−30 amu) that dissociates into dephytyllated deprotonated chlorophyll. Semi-empirical molecular dynamics calculations show that the phytyl chain is unfolded from the chlorin cycle in pheophytin a and folded in chlorophyll a. Density functional theory calculations have been conducted to locate the charges on protonated and deprotonated pheophytin a and chlorophyll a and have found the major location sites that are notably more stable in energy by more than 0.5 eV than the others. The deprotonation site is found identical for pheophytin a and the chlorophyll a-methanol adduct. This is in line with experiment and calculation locating the addition of methanol on a double bond of deprotonated chlorophyll a. [ABSTRACT FROM AUTHOR]

We present a surface sampling method for the chemical analysis of liquid-immersed solid samples. Liquid immersion allows samples to be kept in a hydrated state. We employed cavitation generated by high-intensity focused ultrasound for localized material removal. The appropriate transducer–sample distance was determined using the actuating ultrasound transducer prior to sampling, allowing sonication in focus despite surface height variation. We demonstrate the proposed surface sampling method on water-submerged glass cover slides painted with permanent markers, achieving sampling with tunable spot size down to 500 μ m. The removed and collected material was transferred for chemical analysis by electrospray ionization mass spectrometry, which showed mass peaks characteristic to the permanent markers. [ABSTRACT FROM AUTHOR]

Rationale: To uphold the integrity of horseracing and equestrian sports, it is critical for an equine doping control laboratory to develop a comprehensive screening method to cover a wide range of target substances at the required detection levels in equine urine. Methods: The procedure involved the enzymatic hydrolysis of 3 mL urine samples followed by solid‐phase extraction using HF Bond Elut C18 cartridge. The resulting extracts were then separated on a C18 reversed‐phase column and analyzed using liquid chromatography/high‐resolution mass spectrometry (LC/HRMS) in both electrospray ionization positive and negative modes in two separate injections. The analytical data were obtained in full scan and product ion scan (PIS) modes in an 11 min LC run. Results: The method can detect 1011 compounds (in both positive and negative ion modes). Over 95% of the target compounds have limits of detections (LODs) ≤10 ng/mL, and more than 50% of the LODs are ≤0.5 ng/mL. The lowest LOD can reach down to 0.01 ng/mL. The applicability of the method was demonstrated by the successful detection of prohibited substances in overseas and domestic equine urine samples. Conclusions: We have successfully developed a regular screening method for equine urine samples that can detect more than 1000 compounds at sub‐ppb levels in both positive and negative ion modes with full scan and PIS using LC/HRMS. Furthermore, this method can theoretically be expanded to accommodate an unlimited number of prohibited substances in full‐scan mode. [ABSTRACT FROM AUTHOR]

Ambient Ionization Mass Spectrometry (AI-MS) techniques have revolutionized analytical chemistry by enabling rapid analysis of samples under atmospheric conditions with minimal to no preparation. In this study, the optimization of a cold atmospheric plasma for the analysis of food and pharmaceutical samples, liquid and solid, using a Heat-Assisted Dielectric Barrier Discharge Ionization (HA-DBDI) source is described. A significant enhancement in analyte signals was observed when a heating element was introduced into the design, potentially allowing for greater sensitivity. Furthermore, the synergy between the inlet temperature of the mass spectrometer and the heating element allows for precise control over the analytical process, leading to improved detection sensitivity and selectivity. Incorporating computational fluid dynamic (CFD) simulations into the study elucidated how heating modifications can influence gas transport properties, thereby facilitating enhanced analyte detection and increased signal intensity. These findings advance the understanding of HA-DBDI technology and provide valuable insights for optimizing AI-MS methodologies for a wide range of applications in food and pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

This article discusses the use of lignocellulose, a renewable source of chemical products, for the production of high-value compounds. The authors focus on the nitration of lignin-derived monomeric products, such as vanillin, to produce 5-nitrovanillin. They explore the use of acetyl nitrate as a nitrating agent and highlight its advantages over other methods. The study demonstrates that the nitration of vanillin is highly selective and can be carried out in a simple and efficient manner. The authors hope that this research will contribute to the practical applications of lignin-derived structures and enhance our understanding of their reactivities. [Extracted from the article]

Organic acids are among the primary substances affecting the flavor of 'Fenjiao' bananas. Several previous studies have characterized organic acids and their corresponding biosynthetic pathways in 'Fenjiao' bananas; however, chemical information about the spatial and temporal distributions of the organic acids in the bananas is absent. In this study, air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) for analyzing organic acids in 'Fenjiao' bananas was developed. The organic acids in the peel and pulp of 'Fenjiao' bananas were detected and imaged in situ, and the spatial distribution of organic acids in banana fruit tissue slices were visualized. The results were validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that the MSI method can provide more accurate spatial and chemical localizations of the four primary organic acids (i.e., citric, malic, fumaric, and quinic acids) in the same tissues of 'Fenjiao' bananas. However, the quantification of the concentrations in different tissues is adversely affected by inaccuracy due to matrix effects. The in situ determination of the organic acids in 'Fenjiao' bananas can assist to understand the spatial and temporal distribution of organic acids in bananas, which provides a new method and idea to explore the biosynthesis and accumulation pattern of metabolites. [ABSTRACT FROM AUTHOR]

Background: Selection of the most promising radiotracer candidates for radiolabeling is a difficult step in the development of radiotracer pharmaceuticals, especially for the brain. Mass spectrometry (MS) is an alternative to study ex vivo the characteristics of candidates, but most MS studies are complicated by the pharmacologic doses injected and the dissection of regions to study candidate biodistribution. In this study, we tested the ability of a triple quadrupole analyzer (TQ LC–MS/MS) to quantify low concentrations of a validated precursor of a radiotracer targeting the DAT (LBT-999) in dissected regions. We also investigated its biodistribution on brain slices using MS imaging with desorption electrospray ionization (DESI) coupled to time-of-flight (TOF) vs. TQ mass analyzers. Results: TQ LC–MS/MS enabled quantification of LBT-999 injected at sub-tracer doses in dissected striata. DESI-MS imaging (DESI-MSI) with both analyzers provided images of LBT-999 biodistribution on sagittal slices that were consistent with positron emission tomography (PET). However, the TOF analyzer only obtained biodistribution images at a high injected dose of LBT-999, while the TQ analyzer provided biodistribution images at lower injected doses of LBT-999 with a better signal-to-noise ratio. It also allowed simultaneous visualization of endogenous metabolites such as dopamine. Conclusions: Our results show that LC-TQ MS/MS in combination with DESI-MSI can provide important information (biodistribution, specific and selective binding) that can facilitate the selection of the most promising candidates for radiolabeling and support the development of radiotracers. [ABSTRACT FROM AUTHOR]

\nHIGHLIGHTSHemp (Cannabis sativa L.) is an important source of fibre and seed oil and protein. By-products of industrial hemp fibre production, like hemp seeds and cakes, can be used as feed for all animal species as fat and protein source and the whole hemp plant (including stalk and leaves) might be a suitable fibre source for ruminants. However, a previous feeding experiment with leaf-flower-seed hemp silage, made from an industrial hemp variety, demonstrated detrimental effects on cow health parameters and a significant transfer of several cannabinoids, including the psychoactive tetrahydrocannabinol (∆9-THC), into cow’s milk, posing a potential risk to the safety of consumers. Based on those observations, the present study tested the hypothesis that anaerobic fermentation, as during ensiling, increases the content of ∆9-THC in hemp. Therefore, silages of whole plants from the industrial hemp Cannabis sativa L. var. Ivory were prepared in a multifactorial design, with the four treatments 1) untreated control (CON), 2) addition of 10 mL per kg fresh weight homofermentative lactobacilli at 105 cfu/mL (LBAC), 3) addition of 10 mL per kg fresh weight homofermentative lactobacilli at 105 cfu/mL plus 30 g molasses (LBACmol) and 4) addition of propionic acid (10 mL/kg fresh weight) (PRO). Ultra high performance liquid chromatography coupled with tandem mass spectrometry with electrospray ionisation (UHPLC-MS/MS) was performed for analysis of cannabinoids in fresh hemp material and after 10 and 90 days of ensiling. The study revealed that ensiling decreased all acid forms of analysed cannabinoids in hemp at about 40–65% of the initial values after 90 days of storage, with the exception of cannabinolic acid (CBNA), and CBGA, the acidic form of cannabigerol (CBG). This decrease in most acidic forms was accompanied by an increase of the corresponding non-acidic forms of all cannabinoids, including the psychoactive ∆9-THC. Thus, although ensiling decreases the total cannabinoid content, psychoactive compounds like ∆9-THC can increase, enhancing the risk for animal health and a transfer of these substances into animal derived products. Industrial hemp can be ensiled with different additives, despite its high buffering capacityUltra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was used for analysis of cannabinoidsEnsiling decreased total cannabinoid content in industrial hemp, but increased individual compounds like ∆9-THC, likely through decarboxylation of the precursor ∆9-THCA.Industrial hemp can be ensiled with different additives, despite its high buffering capacityUltra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was used for analysis of cannabinoidsEnsiling decreased total cannabinoid content in industrial hemp, but increased individual compounds like ∆9-THC, likely through decarboxylation of the precursor ∆9-THCA. [ABSTRACT FROM AUTHOR]

Almond-based beverages are valued for their functionalities. However, cases of adulteration are found in the literature aiming to reduce costs. In this study, almond (LA) and peanut (LP)-based beverages were used as investigational controls in commercial products analyzed by gas chromatography and direct infusion electrospray ionization mass spectrometry (ESI-MS) combined with principal component analysis (PCA). Thus, characteristic fatty acids were identified in plant-based beverages. The ESI-MS method combined with PCA indicated individualities regarding the disposition of triacylglycerol (TAG) composition, as higher intensities of TAG were found as a lipid marker at m/z 919 [TAG+NH4]+ of ions formed by arachidic (20:0), 8/heptadecenoic (17:1n-9) and oleic (18:1n-9) fatty acids in LP. The technique demonstrated efficiency in the detection of fraud due to its sensitivity, identifying peanut content in three almond-based commercial beverages (4.4–11.58%). This study highlights the importance of robust analytical methods to the authenticity and quality of food products. [ABSTRACT FROM AUTHOR]

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

Rationale: Silver doping of electrospray is known to increase the abundance of olefinic compounds detected by mass spectrometry. While demonstrated in targeted experiments, this has yet to be investigated in an untargeted study. Utilizing infrared matrix-assisted laser desorption electrospray ionization mass spectrometry imaging (IR-MALDESI-MSI), an untargeted lipidomics experiment on mouse liver was performed to evaluate the advantages of silver-doped electrospray. Methods: 10 ppm silver nitrate was doped into the IR-MALDESI solvent consisting of 60% acetonitrile and 0.2% formic acid. Using an Orbitrap mass spectrometer in positive ionization mode, MSI was performed, analyzing from m/z 150 to m/z 2000 to capture all lipids with potential silver adducts. The lipids detected in the control and silver-doped electrosprays were compared by annotating using the LIPID MAPS Structural Database and eliminating false positives using the metabolite annotation confidence score. Results: Silver-doped electrospray allowed for the detection of such ions of lipid molecules as [M + H]+ or [M + NH4]+ and as [M + Ag]+. Among the ions seen as [M + H]+ or [M + NH4]+, the signal was comparable between the control and silver-doped electrosprays. The silver-doped electrospray led to a 10% increase in the number of detected lipids, all of which contained a bay region increasing the interaction between silver and alkenes. Silver preferentially interacted with lipids that did not contain hard bases such as phosphates. Conclusions: Silver-doped electrospray enabled detection of 10% more olefinic lipids, all containing bay regions in their putative structures. This technique is valuable for detecting previously unobserved lipids that have the potential to form bay regions, namely fatty acyls, glycerolipids, prenol lipids, and polyketides. [ABSTRACT FROM AUTHOR]

Polyglycolic acid (PGA) is a biologically friendly material with a wide range of applications. The production of dimethyl oxalate using coal-based syngas and the hydrogenation of dimethyl oxalate can produce the polymerization raw material of PGA, glycolide, which requires a methyl glycolate polymerization and depolymerization process. The intermediate products of the production process were analyzed using gas chromatogram-mass spectrometry (GC-MS) and Orbitrap mass spectrometry (Orbitrap MS), which revealed the presence of cyclic and linear PGAs with different capped ends. The impurities present in the oligomer were mostly methyl-capped PGA and were retained in the subsequent depolymerization process to glycolide, solvent washing can be used to remove this part of the impurity and ultimately obtain a refined glycolide product. Furthermore, it is proposed that the use of the specialized Kendrick Mass Defect (KMD) to plot and analyze PGA compounds obtained using mass spectrometry can enable the direct classification of PGAs without the need for exact molecular formula assignment. [ABSTRACT FROM AUTHOR]

The synthesis of eleven new nickel Schiff base complexes each bearing four pendant groups is reported. The structures of the complexes differ in the identity of the pendant groups and/or diamine moiety. All complexes were characterised by microanalysis, Nuclear Magnetic Resonance (NMR) spectroscopy and Electrospray Ionisation Mass Spectrometry (ESI-MS), while the solid-state structures of two of the molecules were also determined using X-ray crystallographic methods. The DNA binding properties of the nickel complexes with double stranded DNA and a range of G-quadruplex DNA structures was explored using different spectroscopic methods as well as computational techniques. Results from ESI-MS experiments and Fluorescent Indicator Displacement (FID) assays were consistent with each other and indicated that varying the diamine moiety had less influence on DNA affinity than changing the pendant groups. These conclusions were also generally supported by results obtained from UV melting experiments and Fluorescence Resonance Energy Transfer (FRET) assays. The cytotoxicity of selected examples of the new complexes, and close analogues reported recently, towards V79 Chinese hamster lung cancer cells and THP-1 human leukemia cells was measured. All were found to display modest cytotoxicity, with flow cytometry experiments suggesting an apoptotic pathway was the most likely mechanism of cell death. [ABSTRACT FROM AUTHOR]

One‐step purification of ethylene from ternary mixtures (C2H2, C2H4, and C2H6) can greatly reduce the energy consumption of the separation process, but it is extremely challenging. Herein, we use crystal engineering and reticular chemistry to introduce unsaturated bonds (ethynyl and alkyne) into ligands, and successfully design and synthesized two novel Zr‐MOCs (ZrT‐1‐ethenyl and ZrT‐1‐alkyne). The introduction of carbon‐carbon unsaturated bonds provides abundant adsorption sites within the framework while modulating the pore window size. Comprehensive characterization techniques including single crystal and powder X‐ray diffraction, as well as electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOF‐MS) confirm that ZrT‐1‐ethenyl and ZrT‐1‐alkyne possess an isostructural framework with ZrT‐1 and ZrT‐1‐Me, respectively. Adsorption isotherms and breakthrough experiments combined with theoretical calculations demonstrate that ZrT‐1‐ethenyl can effectively remove trace C2H2 and C2H6 in C2H4 and achieve separation of C2H2 from C2H4 and CO2. ZrT‐1‐ethenyl can also directly purify C2H4 in liquid solutions. This work provides a benchmark for MOCs that one‐step purification of ethylene from ternary mixtures. [ABSTRACT FROM AUTHOR]

We report the syntheses of tin(II) salts of the types [L1SnX]SnX3 [L1=2,6‐{(i‐PrO)2(O)P}2C5H3N: 1, X=Cl; 2, X=Br], [L2SnCl]SnCl3 [L2=2‐{(i‐PrO)Ph(O)P}‐6‐{(i‐PrO)2(O)P}C5H3N: 3], [L3SnX]SnX3 [L3=2,6‐{MeO(O)C}2C5H3N: 4, X=Cl; 5, X=Br], [L4SnX]SnX3 [L4=2,6‐{Et2N(O)C}2C5H3N: 6, X=Cl; 7, X=Br]. These compounds were obtained by addition of SnX2 to the corresponding ligand inducing autoionization of the respective tin(II) halide. The thermal stability of 1, 3, and 4 was elucidated, giving, under ester cleavage and cyclisation, the tin(II) derivatives 8–12. The reaction of [L1SnCl]SnCl3 (1) with W(CO)4(thf)2 afforded the tungsten tetracarbonyl complex [{L1SnCl}{SnCl3}W(CO)4] (13), representing the first example in which a tin(II) stannate anion and a tin(II) stannylium cation simultaneously coordinate to a transition metal centre. The compounds were characterized by single crystal X‐ray diffraction analyses and in part by elemental analyses, IR and NMR spectroscopy, electrospray ionization mass spectrometry. DFT calculations accompany the experimental work. [ABSTRACT FROM AUTHOR]

L-Phenylalanine (L-Phe), which is one of the essential amino acids, is important for the human body because it is used in the biosynthesis of neurotransmitters. Phenylalanine dehydrogenase (PheDH) has been studied as a material for the L-Phe sensor. In particular, the accurate and simple determination of L-Phe concentrations in human samples is needed for the diagnosis and treatment of patients with phenylketonuria. Thermostable PheDH from the bacterium Thermoactinomyces intermedius is suitable as a sensor material; however, it is reactive to not only L-Phe but also L-tyrosine (L-Tyr). Thus, we attempted to improve its substrate specificity for the accurate measurement of L-Phe. In this study, we developed the PheDH mutant with improved substrate specificity by amino acid substitution. The PheDH mutant, in which the 290th asparagine residue was substituted with aspartic acid (N290D), is considered to form a new interaction in the substrate binding site and has a markedly reduced reactivity with L-Tyr compared with the wild-type PheDH; the relative activities (L-Tyr/L-Phe) of the wild-type PheDH and the PheDH N290D mutant were 64.0 and 1.5%, respectively. An enzymatic assay using this mutant was established to quantify the L-Phe concentration in human plasma. The relative errors ranged from −10.3 to 7.4% when compared with the quantitative value determined by high-performance liquid chromatography/electrospray ionization mass spectrometry. Furthermore, the immobilized mutant showed a concentration-dependent reactivity with L-Phe and no reactivity with L-Tyr, which indicate its potential use as a sensor material. [ABSTRACT FROM AUTHOR]

Mass spectrometry imaging (MSI) is used for visualizing the distribution of components in solid samples, such as biological tissues, and requires a technique to ionize the components from local areas of the sample. Tapping-mode scanning probe electrospray ionization (t-SPESI) uses an oscillating capillary probe to extract components from a local area of a sample with a small volume of solvent and to perform electrospray ionization of those components at high speed. MSI can be conducted by scanning the sample surface with a capillary probe. To ensure stable extraction and ionization for MSI, the probe oscillation during measurements must be understood. In this study, we examined the changes in oscillation amplitude and phase due to the interaction between the oscillating probe and the brain tissue section when the probe tip was dynamically brought close to the sample surface. The changes in the probe oscillation depended on the oscillation frequency and polarity of the bias voltage applied to the solvent because an electrostatic force shifted the frequency of the probe oscillation. These findings suggest that controlling the probe oscillation frequency is important for stabilizing MSI by t-SPESI. [ABSTRACT FROM AUTHOR]

In this work, we employed a new ambient ionization mass spectrometry technique, sandpaper spray mass spectrometry (SPS‐MS), as an efficient tool to analyze pills and tablets of pharmaceutical formulations. The following samples were analyzed: regulators of blood pressure, cholesterol, and diabetes, and drugs for the treatment of erectile dysfunction (ED). Additionally, a hard candy of Cannabis sativa containing Δ9‐tetrahydrocannabinol (Δ9‐THC) and its related isomer cannabidiol (CBD) was also evaluated. The surfaces of the samples, without any prior treatment, were sanded onto triangular‐cut sandpaper, and full MS scans (and MS/MS) were acquired in both positive and negative ionization modes. SPS‐MS (and MS/MS) allowed for prompt detection of the active pharmaceutical ingredients (APIs) in each formulation. Other components of the formulations, added as excipients, were also tentatively identified. The results described herein indicate that the SPS‐MS technique can be applied to fast screening of pills and tablets being potentially used as an efficient tool to detect counterfeit pharmaceutical and illicit products, a current issue of increasing concern. [ABSTRACT FROM AUTHOR]

This article discusses the isolation and identification of four new compounds from the leaves of Turpinia montana Kurz, a medicinal plant used in Vietnam. The compounds were analyzed using techniques such as NMR spectroscopy and mass spectrometry. The study provides valuable information for further research on the phytochemical properties of Turpinia montana. The document describes the experimental procedures, results, and spectral data for the compounds, as well as acknowledging the financial support received for the research. Supplementary figures showing the spectra of the compounds are also included. [Extracted from the article]

In this study we demonstrated for the first time synthetic procedures for composites of salinomycin (SalH) and two-line ferrihydrite. The products were characterized by various methods such as elemental analysis, attenuated total reflectance–Fourier-transform spectroscopy (ATR-FTIR), electron paramagnetic resonance spectroscopy (EPR), powder X-ray diffraction analysis (XRD), electrospray-ionization mass spectrometry (ESI-MS), thermogravimetric analysis with differential thermal analysis (DTA) and mass spectrometry (TG-DTA/MS). The EPR spectra of the isolated compounds consisted of signals associated with both isolated Fe3+ ions and magnetically coupled Fe3+ ions. Powder XRD analyses of the isolated products showed two intense and broad peaks at 9° and 15° 2Θ, corresponding to salinomycinic acid. Broad peaks with very low intensity around 35°, assigned to two-line ferrihydrite, were also registered. Based on the experimental results, we concluded that salinomycin sodium reacted with Fe(III) chloride to form composites consisting of two-line ferrihydrite and salinomycinic acid. One of the composites exerted pronounced antitumor activity in the sub-micromolar concentration range against human cervical cancer (HeLa), non-small-cell lung cancer (A549), colon cancer (SW480), and ovarian teratocarcinoma (CH1/PA1) cells. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) obtained from 5‐(hydroxymethyl)furfural (5‐HMF) were activated by a 365 nm‐UV irradiation source and employed in the Knoevenagel condensation to investigate their photocatalytic mechanism. To this end, electrospray ionization mass spectrometry (ESI‐MS) was used to monitor the time progress of the condensation and follow the formation of the final product in positive and negative ion modes at once. The intervention of the superoxide radical anion in the photocatalytic mechanism of CDs was highlighted. [ABSTRACT FROM AUTHOR]

Three new tridentate copper(II) N-heterocyclic carbene (NHC) complexes have been obtained and characterized with symmetrical C-4 substitutions on their pendent pyridine rings. Substitutions including methyl (Me), methoxy (OMe), and chloro (Cl) groups, which extend the library pincer Cu-NHC complexes under investigation, modify the impact of pyridinyl basicity on NCN pincer complexes. Both ligand precursors and copper(II) complexes are characterized using a range of techniques, including nuclear magnetic resonance (NMR) spectroscopy for 1H, 13C, 31P, and 19F nuclei, electrospray ionization mass spectrometry (ESI-MS), X-ray crystallography, cyclic voltammetry, and UV-Vis spectroscopy. The pyridine substitutions lead to minimal changes to bond lengths and angles in the X-ray crystal structures of these related complexes; there is a pronounced impact on the electrochemical behavior of both the ligand precursors and copper complexes in the solution. The substitution in the pyridinyl units of these complexes show an impact on the catalytic reactivity of these complexes as applied to a model C–N bond-forming reaction (CEL cross-coupling) under well-established conditions; however, this observation does not correlate to the expected change in basicity in these ligands. [ABSTRACT FROM AUTHOR]

This study investigates the anti-inflammatory, analgesic, and antioxidant properties of polyphenols extracted from Brassica oleracea var. capitata (cabbage) ethanolic extract (BOE). Given the historical use of cabbage in traditional medicine for treating various ailments, this research aims to validate these effects scientifically. The study involved the characterization of BOE's bioactive compounds using Fourier Transform Infrared Spectroscopy (FTIR) and Liquid Chromatography–Diode Array Detection–Electro-Spray Ionization Mass Spectrometry (HPLC-DAD-ESI MS) analysis. We assessed the anti-inflammatory and analgesic effects of topical and oral BOE administration on rodent models with acute and subacute inflammation. Additionally, the antioxidant capacity of orally administered BOE was evaluated. The results showed that BOE possesses significant levels of phenolic compounds with a potent antioxidant activity. The topical administration of BOE demonstrated notable anti-inflammatory effects in the tested rodent models, which were comparable with nonsteroidal anti-inflammatory drugs. These findings suggest that BOE could be a valuable natural remedy for inflammation-related conditions, supporting its traditional uses and highlighting its potential for further pharmacological development. [ABSTRACT FROM AUTHOR]

Worldwide, it is estimated that there are 1.8 to 2.7 million cases of envenoming caused by snakebites. Snake venom is a complex mixture of protein toxins, lipids, small molecules, and salts, with the proteins typically responsible for causing pathology in snakebite victims. For their chemical characterization and identification, analytical methods are required. Reversed-phase liquid chromatography coupled with electrospray ionization mass spectrometry (RP-LC-ESI-MS) is a widely used technique due to its ease of use, sensitivity, and ability to be directly coupled after LC separation. This method allows for the efficient separation of complex mixtures and sensitive detection of analytes. On the other hand, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is also sometimes used, and though it typically requires additional sample preparation steps, it offers desirable suitability for the analysis of larger biomolecules. In this study, seven medically important viperid snake venoms were separated into their respective venom toxins and measured by ESI-MS. In parallel, using nanofractionation analytics, post-column high-resolution fractionation was used to collect the eluting toxins for further processing for MALDI-MS analysis. Our comparative results showed that the deconvoluted snake venom toxin masses were observed with good sensitivity from both ESI-MS and MALDI-MS approaches and presented overlap in the toxin masses recovered (between 25% and 57%, depending on the venom analyzed). The mass range of the toxins detected in high abundance was between 4 and 28 kDa. In total, 39 masses were found in both the ESI-MS and/or MALDI-MS analyses, with most being between 5 and 9 kDa (46%), 13 and 15 kDa (38%), and 24 and 28 kDa (13%) in size. Next to the post-column MS analyses, additional coagulation bioassaying was performed to demonstrate the parallel post-column assessment of venom activity in the workflow. Most nanofractionated venoms exhibited anticoagulant activity, with three venoms additionally exhibiting toxins with clear procoagulant activity (Bothrops asper, Crotalus atrox, and Daboia russelii) observed post-column. The results of this study highlight the complementarity of ESI-MS and MALDI-MS approaches for characterizing snake venom toxins and provide a complementary overview of defined toxin masses found in a diversity of viper snake venoms. [ABSTRACT FROM AUTHOR]

Radix ginseng and Schisandra chinensis have been extensively documented in traditional Chinese medicine (TCM) for their potential efficacy in treating dementia. However, the precise mechanism of their therapeutic effects remains to be fully elucidated. In this study, air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) and network pharmacology are used to investigate the pharmacodynamics and mechanism underlying the herbal combination consisting of Radix ginseng-Schisandra chinensis (RS) in a rodent model for Alzheimer's disease (AD). Brain histopathological findings suggested that RS attenuates hippocampal damage in AD mice, making this combination a potential AD treatment. Twenty-eight biomarkers were identified by spatial metabolomics analysis, which are intricately linked to neuroinflammation, neurotransmitter imbalance, energy deficiency, oxidative stress, and aberrant fatty acid metabolism in AD. The total extract of RS (TE) affected 22 of these biomarkers, with the small molecule components of RS (SN) significantly influencing 19 and the large molecule components of RS (PR) impacting 14. Nine small molecule components are likely to dominate the pharmacodynamics of RS. We constructed a target interaction network based on the corresponding bioactivities that revealed relationships amongst 11 key biomarkers, 8 active ingredients and 12 critical targets. This research illustrates the immense potential of spatial metabolomics and network pharmacology in the study of TCM, revealing the targets and mechanisms underlying herbal formulas. [ABSTRACT FROM AUTHOR]

With the advent of soft ionization techniques such as electrospray (ESI) and matrix‐assisted laser desorption/ionization (MALDI) to produce intact gas‐phase ions from nonvolatile macromolecules, mass spectrometry has become an essential technique in the field of polymeric materials. However, (co)polymers of very high molecular weight or with reticulated architectures still escape ESI or MALDI, mainly due to solubility issues. Strategies developed to tackle such an analytical challenge all rely on sample degradation to produce low‐mass species amenable to existing ionization methods. Yet, chain degradation needs to be partial and controlled to generate sufficiently large species that still contain topological or architectural information. The present article reviews the different analytical degradation strategies implemented to perform mass spectrometry of these challenging synthetic polymers, covering thermal degradation approaches in sources developed in the 2000s, off‐line sample pre‐treatments for controlled chemical degradation of polymeric substrates, and most recent achievements employing reactive ionization modes to perform chemolysis on‐line with MS. [ABSTRACT FROM AUTHOR]

The prevalent life-threatening microbial and cancer diseases and lack of effective pharmaceutical therapies created the need for new molecules with antimicrobial and anticancer potential. Bee venom (BV) was collected from honeybee workers, and melittin (NM) was extracted from BV and analyzed by urea-polyacrylamide gel electrophoresis (urea-PAGE). The isolated melittin was hydrolyzed with alcalase into new bioactive peptides and evaluated for their antimicrobial and anticancer activity. Gel filtration chromatography fractionated melittin hydrolysate (HM) into three significant fractions (F1, F2, and F3), that were characterized by electrospray ionization mass spectrometry (ESI-MS) and evaluated for their antimicrobial, anti-biofilm, antitumor, and anti-migration activities. All the tested peptides showed antimicrobial and anti-biofilm activities against Gram-positive and Gram-negative bacteria. Melittin and its fractions significantly inhibited the proliferation of two types of cancer cells (Huh-7 and HCT 116). Yet, melittin and its fractions did not affect the viability of normal human lung Wi-38 cells. The IC50 and selectivity index data evidenced the superiority of melittin peptide fractions over intact melittin. Melittin enzymatic hydrolysate is a promising novel product with high potential as an antibacterial and anticancer agent. [ABSTRACT FROM AUTHOR]

This review presents progress made in the ambient analysis of proteins, in particular by desorption electrospray ionization‐mass spectrometry (DESI‐MS). Related ambient ionization techniques are discussed in comparison to DESI‐MS only to illustrate the larger context of protein analysis by ambient ionization mass spectrometry. The review describes early and current approaches for the analysis of undigested proteins, native proteins, tryptic digests, and indirect protein determination through reporter molecules. Applications to mass spectrometry imaging for protein spatial distributions, the identification of posttranslational modifications, determination of binding stoichiometries, and enzymatic transformations are discussed. The analytical capabilities of other ambient ionization techniques such as LESA and nano‐DESI currently exceed those of DESI‐MS for in situ surface sampling of intact proteins from tissues. This review shows, however, that despite its many limitations, DESI‐MS is making valuable contributions to protein analysis. The challenges in sensitivity, spatial resolution, and mass range are surmountable obstacles and further development and improvements to DESI‐MS is justified. [ABSTRACT FROM AUTHOR]

Capturing short‐lived intermediates at the molecular level is key to understanding the mechanism and dynamics of chemical reactions. Here, we have developed a paper‐in‐tip bipolar electrolytic electrospray mass spectrometry platform, in which a piece of triangular conductive paper incorporated into a plastic pipette tip serves not only as an electrospray emitter but also as a bipolar electrode (BPE), thus triggering both electrospray and electrolysis simultaneously upon application of a high voltage. The bipolar electrolysis induces a pair of redox reactions on both sides of BPE, enabling both electro‐oxidation and electro‐reduction processes regardless of the positive or negative ion mode, thus facilitating access to complementary structural information for mechanism elucidation. Our method enables real‐time monitoring of transient intermediates (such as N,N‐dimethylaniline radical cation, dopamine o‐quinone (DAQ) and sulfenic acid with half‐lives ranging from microseconds to minutes) and transient processes (such as DAQ cyclization with a rate constant of 0.15 s−1). This platform also provides key insights into electrocatalytic reactions such as Fe (III)‐catalyzed dopamine oxidation to quinone species at physiological pH for neuromelanin formation. [ABSTRACT FROM AUTHOR]

The chemical and biological conversion of biomass-derived lignin is a promising pathway for producing valuable low molecular weight aromatic chemicals, such as vanillin or guaiacol, known as lignin monomers (LMs). Various methods employing chromatography and electrospray ionization-mass spectrometry (ESI–MS) have been developed for LM analysis, but the impact of LM chemical properties on analytical performance remains unclear. This study systematically optimized ESI efficiency for 24 selected LMs, categorized by functionality. Fractional factorial designs were employed for each LM to assess ESI parameter effects on ionization efficiency using ultra-high-performance supercritical fluid chromatography/ESI–MS (UHPSFC/ESI–MS). Molecular descriptors were also investigated to explain variations in ESI parameter responses and chromatographic retention among the LMs. Structural differences among LMs led to complex optimal ESI settings. Notably, LMs with two methoxy groups benefited from higher gas and sheath gas temperatures, likely due to their lower log P and higher desolvation energy requirements. Similarly, vinyl acids and ketones showed advantages at elevated gas temperatures. The retention in UHPSFC using a diol stationary phase was correlated with the number of hydrogen bond donors. In summary, this study elucidates structural features influencing chromatographic retention and ESI efficiency in LMs. The findings can aid in developing analytical methods for specific technical lignins. However, the absence of an adequate number of LM standards limits the prediction of LM structures solely based on ESI performance data. [ABSTRACT FROM AUTHOR]

A workflow has been evaluated that utilizes a single tissue section to obtain spatially co-registered, molecular, and phenotypical information suitable for AI-enabled image analysis. Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was used to obtain molecular information followed by conventional histological staining and immunolabelling. The impact of varying DESI-MSI conditions (e.g., heated transfer line (HTL) temperature, scan rate, acquisition time) on the detection of small molecules and lipids as well as on tissue integrity crucial for integration into typical clinical pathology workflows was assessed in human kidney. Increasing the heated transfer line temperature from 150 to 450 °C resulted in a 1.8-fold enhancement in lipid signal at a scan rate of 10 scans/s, while preserving histological features. Moreover, increasing the acquisition speed to 30 scans/s yielded superior lipid signal when compared to 10 scans/s at 150 °C. Tissue morphology and protein epitopes remained intact allowing full histological assessment and further multiplex phenotyping by immunofluorescence (mIF) and immunohistochemistry (mIHC) of the same section. The successful integration of the workflow incorporating DESI-MSI, H&E, and immunolabelling on a single tissue section revealed an accumulation of ascorbic acid in regions of focal chronic inflammatory cell infiltrate within non-cancerous kidney tissue. Additionally, a strong positive correlation between PI 38:3 and proliferating cells was observed in clear cell renal cell carcinoma (ccRCC) showing the utility of this approach in uncovering molecular associations in disease pathology. [ABSTRACT FROM AUTHOR]

Although numerous ambient ionization mass spectroscopy technologies have been developed over the past 20 years to address diverse analytical circumstances, a single-ion source technique that can handle all analyte types is still lacking. Here, a wide-energy programmable microwave plasma-ionization mass spectrometry (WPMPI-MS) system is presented, through which MS analysis can achieve high coverage of substances with various characteristics by digitally regulating the microwave energy. In addition, ionization energy can be rapidly scanned using programmable waveforms, enabling the simultaneous detection of biomolecules, heavy metals, non-polar molecules, etc., in seconds. WPMPI-MS performs well in analyzing real samples, rapidly analyzing nine toxicological standards in one drop of serum, and demonstrating good quantification and liquid chromatography coupling capability. The WPMPI-MS has also been used to detect soil extracts, solid pharmaceuticals, and landfill leachate, further demonstrating its robust analytical capabilities for real samples. The prospective uses of the technology in biological and chemical analysis are extensive, and it is anticipated to emerge as a viable alternative to commercially available ion sources. Ion source technology in mass spectrometry still has limitations in analyte coverage. Here, the authors present a wide-energy programmable microwave plasma ionization mass spectrometry system that enables MS analysis with high coverage. [ABSTRACT FROM AUTHOR]

Rationale: Contamination of everyday goods with heavy metals such as nickel, cadmium, and lead known to be hazardous to the health of customers is an ongoing problem. Method: Here, a mass spectrometric screening method based on reactive desorption electrospray ionization (DESI) is presented for the analysis of metals in consumer goods such as jewelry, tableware, and paintings. The method detects oxidized species of lead, nickel, cadmium, copper, and iron from the surface of objects without sample preparation. Positively charged metal ions form singly and doubly negatively charged complexes with ethylenediaminetetraacetic acid added to the DESI solvent, which are analyzed by a mass spectrometer. Results: Qualitative and quantitative performance of the method was elucidated with metal salt standards. Subsequently, authentic samples were analyzed qualitatively. Reactive DESI‐MS was able to detect lead and cadmium in eight out of nine consumer goods. For tableware, these heavy metals were found to be localized in the print as determined by reactive DESI imaging. In addition, mockup paintings generated from modern and historical pigments of Pb, Cu, Cd, and Fe in various media (acrylic binder, egg tempera, and linseed oil) were measured to show the suitability of the method for art authentication and conservation. Conclusion: The developed method expands the range of analytes accessible by DESI‐MS to metal ions. Hence, DESI becomes a suitable ionization technique for an increasing number of analyte classes, which are of interest in chemical screening of consumer goods. [ABSTRACT FROM AUTHOR]

Introduction: Distinguishing and categorizing the origin of garlic are highly significant, considering its widespread use as a flavoring agent. With billions of dollars annually in global trade, garlic is frequently susceptible to fraudulent practices. Methodology: Paper spray ionization mass spectrometry (PS‐MS) was employed to quickly analyze garlic samples from distinct geographic origins: China and Brazil. The so‐generated PS‐MS data were treated with metabolomic multivariate approaches, and the garlic samples from these different geographic regions were easily discriminated. Results: Brazilian garlic was characterized to contain higher levels of amino acids, such as arginine, proline, and valine, and organosulfur compounds, such as allicin, alliin, and l‐γ‐glutamil‐S‐allyl‐l‐cysteine, compared to Chinese garlic. The PS‐MS data were treated employing multivariate approaches, typically used in the metabolomics field, and this protocol was promptly able to discern among both types of samples. Conclusion: Hence, this combined strategy holds promise not only as an effective tool for the authentication of the geographical origin of garlic but also as a powerful means for biomarker discovery. [ABSTRACT FROM AUTHOR]

The utilization of grape stems, a by‐product of the grape processing industry, as a source of valuable bioactive compounds, particularly polyphenols, has gained attention in recent years. This study aimed to investigate different eco‐friendly extraction methods for obtaining polyphenols from grape (Vitis vinifera cv. Bidaneh Sefid) stems, focusing on green solvents and innovative techniques. Four extraction methods were tested, involving the use of water and polyethylene glycol (PEG) as green solvents, along with maceration, microwave, ultrasound, and reduced‐pressure techniques. High‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC–ESI‐MS/MS) was used to characterize and quantify the bioactive compounds in the extracts. A total of 29 polyphenols, including phenolic acids, flavonoids, proanthocyanidins, and stilbenes, were detected. Among the four extraction methods tested, methods 1 (water + microwave + ultrasound + atmospheric pressure) and 2 (water + microwave + ultrasound + reduced pressure) were found to be the most effective. Our study demonstrated that using water and PEG as green solvents, combined with techniques like microwave, ultrasound, and reduced pressure, effectively extracted both hydrophobic and hydrophilic compounds from the grape stems. These findings suggest that further exploration of these methods could lead to the development of value‐added products from grape stems, emphasizing the significance of green extraction techniques for the recovery of polyphenols from winemaking by‐products. [ABSTRACT FROM AUTHOR]

A high‐performance liquid chromatography‐tandem mass spectrometry method has been developed for the determination of irinotecan, 7‐ethyl‐10‐hydroxycamptothecin (SN38), and SN38 glucuronide (SN38G) in rat plasma in the present study. The analytes were separated on a C18 column and a triple‐quadrupole mass spectrometry equipped with an electrospray ionization source was applied for detection. Irinotecan, SN38 and SN38G could be well retained in the C18 column after optimization of mobile phase. A simple protein precipitation was used to pretreat the plasma. The extraction recovery was above 90% and the matrix effect could be negligible. The method was linear over the concentration ranges of 3.46–3458.8 ng/mL for irinotecan, 2.53–2530.0 ng/mL for SN38 and 2.5–2500.0 ng/mL for SN38G. The precision and accuracy was within the acceptable limits. The simple and convenient method was validated and successfully applied to support the pharmacokinetic study and elucidate the mechanism of irinotecan‐induced diarrhea after irinotecan was intravenously injected to the Sprague‐Dawley rats. [ABSTRACT FROM AUTHOR]

The skin surface is an important sample source that the metabolomics community has only just begun to explore. Alterations in sebum, the lipid-rich mixture coating the skin surface, correlate with age, sex, ethnicity, diet, exercise, and disease state, making the skin surface an ideal sample source for future noninvasive biomarker exploration, disease diagnosis, and forensic investigation. The potential of sebum sampling has been realized primarily via electrospray ionization mass spectrometry (ESI-MS), an ideal approach to assess the skin surface lipidome. However, a better understanding of sebum collection and subsequent ESI-MS analysis is required before skin surface sampling can be implemented in routine analyses. Challenges include ambiguity in definitive lipid identification, inherent biological variability in sebum production, and methodological, technical variability in analyses. To overcome these obstacles, avoid common pitfalls, and achieve reproducible, robust outcomes, every portion of the workflow—from sample collection to data analysis—should be carefully considered with the specific application in mind. This review details current practices in sebum sampling, sample preparation, ESI-MS data acquisition, and data analysis, and it provides important considerations in acquiring meaningful lipidomic datasets from the skin surface. Forensic researchers investigating sebum as a means for suspect elimination in lieu of adequate fingerprint ridge detail or database matches, as well as clinical researchers interested in noninvasive biomarker exploration, disease diagnosis, and treatment monitoring, can use this review as a guide for developing methods of best-practice. [ABSTRACT FROM AUTHOR]

Objective: The goal was to investigate the role and intracellular regulatory mechanisms of double‐negative T (DNT) cells in the pathogenesis of systemic lupus erythematosus (SLE). Methods: DNT cells were assessed in murine models, patients with SLE, and controls using flow cytometry (FCM). DNT cells from either resiquimod (R848) or vehicle‐treated C57BL/6 (B6) mice were cultured with B cells from R848‐treated mice to explore functions. Differential mechanistic target of rapamycin (mTOR) pathway signaling in DNT cells measured using FCM and quantitative polymerase chain reaction was validated by rapamycin inhibition. Candidate lipid metabolites detected using liquid chromatography with electrospray ionization mass spectrometry/mass spectrometry were functionally assessed in DNT cell cultures. Results: DNT cells were markedly increased in both spontaneous and induced mouse lupus models and in patients with SLE. Expanded DNT cells from R848‐treated B6 mice produced elevated interleukin (IL)‐17A and IgG with increased germinal center B (GCB) cells. Expansion of DNT cells associated with activation of mTORC1 pathway that both IL‐17A levels and the number of DNT cells exhibited dose‐dependent reduction with rapamycin treatment. Lipidomics studies revealed differential patterns of lipid metabolites in T cells of R848‐treated mice. Among candidate metabolites, elevated phosphatidic acid (PA) that was partially controlled by phospholipase D2 increased the expression of the mTORC1 downstream target p‐S6 and positively expanded IL‐17A–producing DNT cells. Similarly, elevated proportions of circulating DNT cells in patients with SLE correlated with disease activity and proteinuria, and IL‐17A secretion was elevated after in vitro PA stimulation. Conclusion: The accumulation of PA in T cells could activate the mTORC1 pathway, promoting DNT cell expansion and IL‐17A secretion, resulting in GCB cell abnormalities in lupus. [ABSTRACT FROM AUTHOR]

Although mechanically interlocked molecules (MIMs) display unique properties and functions associated with their intricate connectivity, limited assembly strategies are available for their synthesis. Herein, we presented a synergistic assembly strategy based on coordination and noncovalent interactions (π-π stacking and CH...π interactions) to selectively synthesize molecular closed three-link chains (6³1 links), highly entangled figure-eight knots (41 knots), trefoil knot (31 knot), and Borromean ring (6³2 link). 6³1 links can be created by the strategic assembly of nonlinear multicurved ligands incorporating a furan or phenyl group with the long binuclear half-sandwich organometallic Cp*RhIII (Cp* = η5-pentamethylcyclopentadienyl) clip. However, utilizing much shorter binuclear Cp*RhIII units for union with the 2,6-naphthyl-containing ligand led to a 41 knot because of the increased π-π stacking interactions between four consecutive stacked layers and CH...π interactions. Weakening such π-π stacking interactions resulted in a 31 knot. The universality of this synergistic assembly strategy for building 41 knots was verified by utilizing a 1,5-naphthyl-containing ligand. Quantitative conversion between the 41 knot and the simple macrocycle species was accomplished by adjusting the concentrations monitored by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Furthermore, increasing the stiff π-conjugated area of the binuclear unit afforded molecular Borromean ring, and this topology is a topological isomer of the 6³1 link. These artificial metalla-links and metalla-knots were confirmed by single-crystal X-ray diffraction, NMR and ESI-MS. The results offer a potent strategy for building higher-order MIMs and emphasize the critical role that noncovalent interactions play in creating sophisticated topologies. [ABSTRACT FROM AUTHOR]

Electrospray ionization mass spectrometry (ESI‐MS) is a powerful tool for identifying and characterizing organometallic and coordination compounds. However, detection of fragile structures bound by weaker intermolecular forces can be significantly limited in ESI‐MS owing to the use of relatively harsh instrument conditions and configurations. In this study, a set of tests was developed to assess the softness of ESI‐MS systems. Two variants are presented: positive ion mode, utilizing a mixture of sodium ions and triphenylphosphine oxide producing [Na(OPPh3)n]+ ions (n=1–4), and negative ion mode utilizing Pd(PPh3)4 and sulfonated triphenylphosphine producing [Pd(L)(PPh3)n]− ions (n=0–2), where softer instrument conditions preserve a higher proportion of the high‐coordinate ions and harsher conditions will result in increased detection of products of ion fragmentation. The results revealed notable variations in instrument softness, which were influenced by a combination of instrument design and experimental parameters. Meticulously optimizing experimental conditions and ESI‐MS parameters is essential to achieving the softest ionization possible, ensuring reliable analysis where applicable. This study offers valuable insight through straightforward tests that can be employed to assess the suitability of an instrument for specific research needs. [ABSTRACT FROM AUTHOR]

Advanced techniques can accelerate the pace of natural product discovery from microbes, which has been lagging behind the drug discovery era. Therefore, the present review article discusses the various interdisciplinary and cutting-edge techniques to present a concrete strategy that enables the high-throughput screening of novel natural compounds (NCs) from known microbes. Recent bioinformatics methods revealed that the microbial genome contains a huge untapped reservoir of silent biosynthetic gene clusters (BGC). This article describes several methods to identify the microbial strains with hidden mines of silent BGCs. Moreover, antiSMASH 5.0 is a free, accurate, and highly reliable bioinformatics tool discussed in detail to identify silent BGCs in the microbial genome. Further, the latest microbial culture technique, HiTES (high-throughput elicitor screening), has been detailed for the expression of silent BGCs using 500–1000 different growth conditions at a time. Following the expression of silent BGCs, the latest mass spectrometry methods are highlighted to identify the NCs. The recently emerged LAESI-IMS (laser ablation electrospray ionization-imaging mass spectrometry) technique, which enables the rapid identification of novel NCs directly from microtiter plates, is presented in detail. Finally, various trending 'dereplication' strategies are emphasized to increase the effectiveness of NC screening. [ABSTRACT FROM AUTHOR]

We developed a Zr two-photon resonance ionization scheme with a high useful yield of 6.3(5)%. This scheme utilizes the known intermediate energy level at 26443.88 cm−1 and a newly characterized Rydberg level at 53490.79(26) cm−1. Both the first (378.16 nm) and second (369.727 nm) transition wavelengths are accessible by frequency-doubled titanium:Sapphire lasers. We utilize the new scheme to analyze the isotopics of Zr, a fission product, in micrometer-sized spent nuclear fuel samples to understand their irradiation history. This includes the dependence on burnup and radial location within a fuel pellet. Resonance ionization mass spectrometry was used to obtain almost isobar-free Zr isotopic ratios from seven samples. The measured isotopic ratios from the spent nuclear fuel show a strong dependence on radial position within the fuel pellet while the effect of average pellet burnup was much less pronounced. All Zr isotopic ratios systematically change from the pellet center to the pellet edge, where isotopic values are close to those expected from 235U fission and 239Pu fission, respectively. Using Zr isotopics, we demonstrate a potential method to distinguish between samples derived from the edge or center of a fuel element of unknown pedigree, which strongly impacts the interpretation of a sample's irradiation history as the neutron fields are different between these locations. [ABSTRACT FROM AUTHOR]

Candida spp. includes opportunistic pathogens that are responsible for superficial and invasive infections. These strains have mechanisms of resistance against antimicrobials. Riparin compounds isolated from the green fruit of the plant Aniba riparia (Nees) Mez, are alkaloids with alkamide function with notable antimicrobial properties. We evaluated the inhibitory effect (in vitro) of Riparins isolated and combined with Fluconazole against strains of Candida albicans , C. tropicalis , and C. krusei ; and in an in silico test, the anti- Candida activity of the factors MdR1, CdR1, and CdR2. Riparins were identified by 1D NMR spectroscopy (1 H and 13 C), electrospray ionization mass spectrometry (ESI-MS), and compared with previously reported spectral data. For the antifungal activity profile, the broth microdilution technique was used (1–1024 µg/mL). For combined antifungal activity, Riparins were tested at fixed subinhibitory concentrations (RI, RII, and RIV of 256 µg/mL and RIII, 64 µg/mL), and FCZ, ranging from 1 to 1024 µg/mL. Minimum Fungicide Concentration was performed by microculture in Petri dishes. For molecular docking, protein sequences were obtained from GenBank; targets were analyzed for homology, and model reliability was assessed using the Ramachandran plot. Composite stratification was performed by the MolDock Score, Rerank Score, PLANTS Score, and Vina Score. The results demonstrated that Riparins I, II, III, and IV, isolated or combined with FCZ have an inhibitory effect on Candida spp. cells, and a high probability of inhibiting antifungal resistance mechanisms, MdR1, CdR1, and CdR2. [Display omitted] • Riparins displayed antifungal action against strains of C. albicans , C. tropicalis and C. krusei. • Riparin III showed higher inhibition values, and lower concentrations than FCZ. • The combination of Riparins with FCZ potentiated the inhibitory effect on Candida strains. [ABSTRACT FROM AUTHOR]

Paphia textile is an economically important bivalve cultured in southeastern China. The feet, as the main edible part of P. textile, vary in color from white to orange. Previous studies have suggested that the orange feet of P. textile contain higher levels of carotenoids than the white feet, but the kinds of carotenoids are not known. The pigments identified in this study can facilitate further analysis of their underlying molecular mechanism and enable the breeding of P. textile with high carotenoid content. The pigments were extracted from the orange feet of P. textile by an acetone extraction method, and then, the extracted pigments were analyzed by liquid chromatography-mass spectrometry (LC-MS). Moreover, the MS analysis was carried out with an electrospray ionization (ESI) source in the positive (ESI+) and negative (ESI-) ion modes. A total of 47 substances were detected, including 9 terpenoids, 7 amino acids and peptides, 13 lipids, 9 organic acids, 2 types of vitamin A and 7 other substances. Furthermore, β-doradecin (3'-hydroxy-3,4-diketo-β-carotene) was identified as the main pigment in the feet. This is the first report of the presence of β-doradecin, a type of carotenoid, in bivalves. [ABSTRACT FROM AUTHOR]

Benefits of miniaturized chromatography with various detection modes, such as increased sensitivity, chromatographic efficiency, and speed, were recognized nearly 50 years ago. Over the past two decades, this approach has experienced rapid growth, driven by the emergence of mass spectrometry applications serving ‐omics sciences and the need for analyzing minute volumes of precious samples with ever higher sensitivity. While nanoscale liquid chromatography (flow rates <1 μL/min) has gained widespread recognition in proteomics, the adoption of microscale setups (flow rates ranging from 1 to 100 μL/min) for low molecular weight compound applications, including metabolomics, has been surprisingly slow, despite the inherent advantages of the approach. Highly heterogeneous matrices and chemical structures accompanied by a relative lack of options for both selective sample preparation and user‐friendly equipment are usually reported as major hindrances. To facilitate the wider implementation of microscale analyses, we present here a comprehensive tutorial encompassing important theoretical and practical considerations. We provide fundamental principles in micro‐chromatography and guide the reader through the main elements of a microflow workflow, from LC pumps to ionization devices. Finally, based on both our literature overview and experience, illustrated by some in‐house data, we highlight the critical importance of the ionization source design and its careful optimization to achieve significant sensitivity improvement. [ABSTRACT FROM AUTHOR]

A new triterpenoid saponin (1), along with five known compounds (2–6), was isolated from Bupleurum marginatum Wall. ex DC, of which compounds 2–4 were obtained for the first time from this plant. The structures were confirmed by the analysis of 1D, 2D NMR, and HR-ESIMS data, and comparison with previous spectral data. Anti-liver fibrotic activities of the isolates were determined as proliferation inhibition of LPS-induced activation of HSC-T6 in vitro. [ABSTRACT FROM AUTHOR]

We have investigated the gas‐phase fragmentation reactions of 11 synthetic 4‐aryl‐3,4‐dihydrocoumarins by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) on a quadrupole‐time‐of flight (Q‐TOF) hybrid mass spectrometer. We have also estimated thermochemical data for the protonated coumarins (precursor ion A) and product ion structures by computational chemistry at a B3LYP level of theory to establish the ion structures and to rationalize the fragmentation pathways. The most abundant ions in the product ion spectra of coumarins 1–11 resulted from C8H8O2, CO2, C4H4O3, C8H10O3, C8H8O2, and CH3OH eliminations through retro‐Diels–Alder (RDA) reactions, remote hydrogen rearrangements (β‐eliminations), and β‐lactone ring contraction. Although the investigated coumarins shared most of the fragmentation pathways, formation of a benzylic product ion and its corresponding tropylium ion was diagnostic of the substituents at ring C. The thermochemical data revealed that the nature and position of the substituents at ring C played a key role in the formation of this product ion and determined its relative intensity in the product ion spectrum. The results of this study contribute to knowledge of the gas‐phase ion chemistry of this important class of organic compounds. [ABSTRACT FROM AUTHOR]

An unprecedented and direct PS‐MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS‐MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium‐contaminated, but the intensities were higher in the former samples. Moreover, long‐time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to development of a new chocolate-flavored powdered food supplement enriched with mesquite pod flour, oak extract and agave fructans, with proper sensory characteristics as well as its physicochemical and glycemic quality. Design/methodology/approach: A powdered shake was formulated using experimental design (23) with mesquite (Prosopis laevigata) pod flour, oak (Quercus convallata) extracts, nonalkalinized cocoa, agave fructans, milk protein and xanthan gum. Sensory analysis (choice profile method, ranking test, focus group, quantitative descriptive analysis), moisture, ash, fiber, protein and lipids, pH, color, wettability, dispersibility and rheological tests were done. Phenolic profiling analysis to samples was done by ultraperformance liquid chromatography coupled to photodiode array detection and electrospray ionization tandem mass spectrometry, antioxidant activity was measured by 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation, ferric reducing antioxidant power and oxygen radical absorbance capacity, glycemic index (GI) and glycemic load were evaluated. Findings: The main sensory attributes in the powders were chocolate, bitter, astringent, grass/linseed flavors (p < 0.05). The product has protein [66.9%], carbohydrates [22.0%], lipids [1.6%], ash [2.7%] and moisture [6.8%], with wettability (23 s), and dispersibility of 77.9%. Catechin, epicatechin, gallocatechin, procyanidin B2, chlorogenic, coumaric and ferulic acids were identified. GI and caloric load not show differences between men (73.3±2.4, 4.4±0.1) and women (67.0±2.1, 4.1±0.1) (p > 0.05). Originality/value: The use of mesquite pods, oak and agave fructans in powder food supplement is an alternative to obtain a product high in protein, with good sensory properties, antioxidant activity and moderate GI. [ABSTRACT FROM AUTHOR]

Background Cassia (Family: Fabaceae) species are a large group of flowering plants rich in bioactive anthraquinone and flavonoids used in botanical supplements and nutraceuticals. Objective A simple and reliable high-performance liquid chromatography-photodiode array (HPLC-PDA) method was developed and validated for separating and quantifying 13 anthraquinone and flavonoids. These compounds were further confirmed using an LC-based electrospray ionization mass spectrometry (ESI-MS/MS) method in the leaves and flowers of selected Cassia species. A simple and rapid HPTLC method was developed for chemical fingerprint analysis of all Cassia species. Method All 13 compounds were chromatographically separated on a Zorbax TC18 (4.6 × 250, 5 μm particle size) analytical column, and 0.1% formic acid and acetonitrile as elution solvents at a flow rate of 0.8 mL/min with detection at 259 nm. For HPTLC fingerprinting, the mobile phase compositions of toluene, ethyl acetate, and formic acid (5.5:4.2:0.6, v/v/v) were optimized to separate and identify all compounds using silica gel 60F254 aluminum plates. Results The validation data for the developed HPLC-PDA method for 13 compounds showed good linearity (r2 >0.99) with a sensitive LOD (0.082–1.969 μg/mL), LOQ (0.250–5.967 μg/mL), and excellent recoveries (85.22–100.32%). The quantification results were found to be precise and accurate (<5.0% and relative error), -0.77–0.44 with ESI-MS/MS confirmation in the Cassia samples. The novel HPTLC method was excellent separation for 13 compounds, with Rf values ranging between 0.12 and 0.61. Conclusions The developed HPLC-PDA method was simple and precise and could separate and quantify anthraquinones and flavonoids along with confirmation, using a novel LC-based ESI-MS/MS. The HPTLC method was found to be simple and precise, with excellent separation capabilities for these compounds. Highlights This novel multiplatform approach successfully identified and quantified 13 compounds simultaneously using an integration of data strategy in seven medicinally important Cassia species' leaves and flowers. [ABSTRACT FROM AUTHOR]