High-resolution Mass Spectrometry Research Articles

Steroids and Epicoccarines from Penicillium aurantiancobrunneum

Lichens are symbiotic organisms comprised of mycobionts and photobiont partners. They are known to produce bioactive secondary metabolites and most of these are biosynthesized by mycobionts. Investigations of cultures of isolated lichen-associated fungi have shown promise for the discovery of cytotoxic compounds. Thus, the lichen-associated fungus Penicillium aurantiacobrunneum was studied for its potential to produce novel compounds and the new sterols (20 S*)-hydroxy-24(28)-dehydrocampesterol (1), 7α-methoxy-8β-hydroxypaxisterol (2), 14-nor-epicoccarine A (3) and 14-nor-epicoccarine B (4), as well as the known compound PF1140 (5), were isolated. The structures of these compounds were elucidated using methods including nuclear magnetic resonance (NMR) spectroscopy and high-resolution electrospray ionization mass spectrometry (HRESIMS). Following cytotoxicity assays, compound 1 demonstrated activity against the pancreatic adenocarcinoma epithelial HPAC cell line at 17.76 ± 5.35 μM. Since the structures of compounds 3 and 4 were very similar to tetramic acid derivatives that were reported to be biosynthesized from a polyketide synthase- non-ribosomal peptide synthetase (PKS-NRPS) hybrid pathway, a plausible biosynthetic route for production in P. aurantiacobrunneum is proposed herein.

Rapid Determination of 12 Classes of Per- and Polyfluoroalkyl Substances in Water Samples from Environmental Forensic Cases.

The widespread use of per- and polyfluoroalkyl substances (PFASs) with different physico-chemical properties poses a great threat to the environment and human health. Simultaneous detection of different classes of PFASs is a difficult task, especially for rapid analysis of polluted water samples in environmental forensic cases. In this study, a simple sample preparation ultrahigh-performance liquid chromatography coupled with quadrupole Orbitrap high-resolution mass spectrometry was established for the detection of PFASs in a wide range of water matrices. By optimizing the conditions of pretreatment and the parameters of the instrument, the developed method provided good linearity of calibration standards (R2 > 0.99), and demonstrated excellent MLOQ (0.008-1.2 µg/L), with spiked recoveries ranging from 57.7% to 151% for 47 targets in surface water samples, and from 45.7 to 165% for 46 targets in ground and waste water samples, respectively. This method required an injection volume of 3 µL and an analysis time of only 18 min per sample. The validation method was successfully applied to the analysis of 20 environmental water samples, in which 15 target substances with different concentrations were detected, with total concentrations of 0.082 to 262.455 μg/L. The method is simple and exclusive, and can rapidly confirm the occurrence of PFASs in different water samples, providing a convenient and fast high-throughput analysis, which is especially suitable for the application in the environmental forensic investigation of PFASs pollution.

“Welcome to the jungle”: TLC-SERS to wade through real complex mixtures of synthetic dyes

The finding of numerous synthetic strategies between the 19th and 20th century fostered the production of an extensive spectrum of organic dyes for artistic and industrial applications. Shortly after, challenges emerged related to the rapid deterioration of these products. Nowadays, the characterization of coloured pieces of art produced in the first half of the XXth century is further complicated by the absence of reference materials with an unambiguous composition, which are frequently a mixture between the starting dyes and their degradations products. Here we demonstrate as Surface Enhanced Raman Spectroscopy coupled with the simplest separation technique, i.e. Thin Layer Chromatography, is able beyond to recognize several synthetic dyes also to identify their isomers and degradation products. The occasion was the study of a catalogue of dyed textile swatches, produced in 1951 by the well-known Italian industry ACNA (Azienda Coloranti Nazionali e Affini). An apparently easy task turned out to be, indeed, not at all obvious as we found out that the actual composition of the reference samples seldomly corresponded to the declared one. TLC-SERS investigation of historical textile swatches was complemented by the integration of liquid chromatography coupled with a diode array detector and high-resolution mass spectrometry (HPLC-DAD-HRMS). This approach allowed us to validate the findings of TLC-SERS and to distinctively characterise synthetic by-products and degradation markers resulting from the deterioration of the dyes.

Green nanoarchitectonics Ce-Co₃O₄/BiVO₄ (p-n) heterojunction nanocomposite: Dual functionality for photodegradation of Congo red and supercapacitor applications

In this work, we synthesised a new Ce-doped Co₃O₄/BiVO₄ heterojunction photocatalyst by a green synthesis strategy utilizing Magnifera indica leaf extract for Co₃O₄ and a precipitation method for pure BiVO₄. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV–Visible diffuse reflectance spectroscopy (UV-DRS), Brunauer-Emmett-Teller (BET) surface area analysis, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) were used to investigate the material's structural, optical The Ce-Co₃O₄/BiVO₄ heterojunction decreased the band gap energy to 1.92 eV, resulting in increased visible light absorption. The photocatalytic activity of the developed heterojunction was evaluated by degrading the anionic dye Congo red (CR) under different circumstances such as pH, catalyst dose, dye concentration, and irradiation period. At pH 4, 98 % degradation was obtained using a dye concentration of 50 ppm, a catalyst dose of 40 mg, and 50 min of sun light exposure. High-resolution mass spectrometry (HR-MS) validated the effective degradation of CR and offered information on the potential degradation process. Kinetic investigations revealed that the photodegradation of CR followed a pseudo-first-order kinetic model. This study demonstrates the effectiveness of Ce-Co₃O₄/BiVO₄ heterojunctions in photocatalytic applications, namely for the removal of dye contaminants from wastewater using visible light. Furthermore, the heterojunction showed a substantial rise in specific capacitance, reaching 1353 F/g, 5.4 times that of pure Co3O4. The Nyquist plot displayed a smaller arc radius, indicating improved electrochemical characteristics and a possible application as a semiconductor. These results highlight the Ce-Co₃O₄/BiVO₄ heterojunction as a promising photocatalyst with outstanding dye degrading capabilities and increased electrochemical performance, appropriate for diverse environmental and energy storage applications.

Prevalence of Drugs of Abuse and Cognitive Enhancer Consumption Monitored in Grab Samples and Composite Wastewater via Orbitrap Mass Spectrometry Analysis.

Wastewater (WW)-based epidemiology is an approach for the objective surveillance of the consumption of (illicit) drugs in populations. The aims of this study were to monitor drugs of abuse, cognitive enhancers, and their metabolites as biomarkers in influent WW. Data obtained from different sampling points and mean daily loads were compared with previously published data. The prevalence of analytes was monitored in WW grab samples collected monthly over 22 months at two sampling points and 24 h composite WW samples collected over 2 weeks at a WW treatment plant in the same city. Quantification was performed using a previously validated and published method based on solid-phase extraction followed by liquid chromatography coupled with high-resolution tandem mass spectrometry. Grab samples allowed for frequent detection of ritalinic acid and sporadic detection of drugs of abuse. The daily mean loads calculated for 24 h WW composite samples were in accordance with data published in an international study. Furthermore, loads of amphetamine and methamphetamine increased compared with those observed in a previously published study from 2014. This study showed frequent quantification of ritalinic acid in the grab samples, while drugs of abuse were commonly quantified in the composite WW samples. Daily mean loads were in accordance with trends reported for Germany.

Establishment of a UPLC-MS method for quantitative analysis of tryptophan-kynurenine metabolism in IBS-D model rats

Background and Aims Abnormalities in tryptophan (TRP) metabolism induce abdominal pain and intestinal motility disorders. The study of TRP metabolism in diarrhea-predominant-irritable bowel syndrome (IBS-D) is important for the prevention, diagnosis, and treatment of this disease. In this study, a rapid and reliable ultra performance liquid chromatography-mass spectrometry (UPLC-MS) method was established to quantify tryptophan-kynurenine (TRP-Kyn) metabolism in the colon of a rat model with IBS-D. Methods The proteins were precipitated by methanol, chromatographically separated on a Welch Ultimate® Polar RP column with a gradient elution for 12 min, and detected by high-resolution tandem mass spectrometry. Pure water were used as an alternative mechanism for standard calibration, and the stable structural analog 2-Cl-Phe was used as an internal standard. Results Within a certain range, the r of TRP, kynurenine (Kyn) and quinolinic acid (QA), kynurenic acid (KA) are greater than 0.99, were found to be accurate and precise. The metabolism of TRP was significantly up-regulated along the Kyn pathway in the IBS-D model rats and normalized after treatment with pivacurium bromide. Conclusion This study investigates the mechanisms of IBS-D gastrointestinal dysfunction from the perspective of colonic TRP metabolism, and also provides new directions for the diagnosis and therapeutic approach of this disease.

Tandem MS Elucidation of the Late-Stage Degradation Mechanism of Nitroplasticizer.

Understanding the degradation behavior of nitroplasticizer (NP) and the subsequent production of nitro-organics is crucial for both environmental monitoring and material development. A nontargeted approach via LC-QTOF-MS was employed to thoroughly study the degradation mechanism of NP in its late aging stage. Both positive and negative modes of ESI were performed to increase the compound coverage. To shed light on the fragmentation behavior of NP degradants (e.g., compounds containing a high density of NO2 moieties and oxygen sites) in the positive mode, which is rarely reported, the high-resolution tandem MS information on precursor ions at m/z 251(+), 254(+), 266(+), and 270(+) and a pair of isomeric ions at m/z 284(+) was investigated to extract their common diagnostic ions and dissociation channels, including the neutral loss of 2,2-dinitropropanol, nitro-nitrite rearrangement, homolytic cleavage of NO2, and simple inductive cleavage. Additionally, leveraging the sensitivity for nitroaromatics in the negative polarity, negative ions m/z 182(-) and 233(-) are identified as dinitroaniline and dinitronaphthol, respectively, which confirm the secondary hydrolysis pathway of the antioxidant (e.g., N-phenyl-2-naphthylamine) postulated in our previous work. In addition to earlier findings, the detection of these eight degradants further supports the evidence of increased acid concentration and aging temperatures in the late-stage NP environment, which contribute to intricate degradation behaviors in different aging environments.

Electrospray ionisation suppression in aquatic dissolved organic matter studies – Investigation via liquid chromatography–mass spectrometry

Ionisation suppression is a persistent issue in electrospray ionisation mass spectrometry, which decreases the signal of co-eluting analytes. In non-targeted analysis, where analyte and organic matrix identity is unknown, this poses a very challenging analytical problem when it comes to quantitatively assessing differences between samples, including in a compositional sense. In this study, I demonstrate the problems that arise due to ionisation suppression using a very simple sample mixing scheme between a fresh, metabolite rich sample (a leaf leachate) and a forest pond water. Samples were analysed after solid phase extraction on Agilent PPL and using high performance liquid chromatography coupled to electrospray ionisation – Orbitrap mass spectrometry, charged aerosol detector and diode array detector, the latter two allowing quantification of eluting material. I found that more than half of the well-resolved analytes expected to be present (at equal concentration) were completely lost from detection after mixing with pond water DOM. The average recovery of analytical signal (i.e., the signal weighted average), was about 50%, and was highly variable between analytes. Ionisation suppression also affected the signal obtained from the geochemical background DOM, and material recovery decreased slightly when mixing samples and extracting at a higher volume on PPL. Overall, the results showed that ionisation suppression is an extremely important problem for comparison of biogeochemical samples, even when only considering presence and absence of detected features. A multi detector approach and liquid chromatographic separation adds great value in comparison to use of only high resolution mass spectrometry (in direct infusion mode).

Artificial intelligence decision making tools in food metabolomics: Data fusion unravels synergies within the hazelnut (Corylus avellana L.) metabolome and improves quality prediction

This study investigates the metabolome of high-quality hazelnuts (Corylus avellana L.) by applying untargeted and targeted metabolome profiling techniques to predict industrial quality. Utilizing comprehensive two-dimensional gas chromatography and liquid chromatography coupled with high-resolution mass spectrometry, the research characterizes the non-volatile (primary and specialized metabolites) and volatile metabolomes. Data fusion techniques, including low-level (LLDF) and mid-level (MLDF), are applied to enhance classification performance. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) reveal that geographical origin and postharvest practices significantly impact the specialized metabolome, while storage conditions and duration influence the volatilome. The study demonstrates that MLDF approaches, particularly supervised MLDF, outperform single-fraction analyses in predictive accuracy. Key findings include the identification of metabolites patterns causally correlated to hazelnut’s quality attributes, of them aldehydes, alcohols, terpenes, and phenolic compounds as most informative. The integration of multiple analytical platforms and data fusion methods shows promise in refining quality assessments and optimizing storage and processing conditions for the food industry.

Breaking down lignin in gamma-valerolactone: advances into a bioelectrorefinery

ABSTRACT This study builds upon our experience with electrocatalyzed dearomatization of lignin in aqueous systems, which has shown to produce sodium levulinate, sodium 4-hydroxyvalerate, sodium acetate, and sodium formate as major products. Here, we extend this investigation by exploring a water/γ-valerolactone (GVL) solvent system for electrochemical depolymerization and dearomatization of lignin, using Na2CO3 as electrolyte. GVL, derived from biomass, has frequently been employed for biomass treatment, notably in the Organosolv process. Consequently, various biorefinery strategies have emerged utilizing GVL as a green platform, primarily for its potential in delignifying lignocellulosic biomass when combined with water and dilute acid. This study proposes electrochemical depolymerization of lignin in GVL as a step toward the concept of a bioelectrorefinery, aiming to convert lignin into aliphatic organic chemicals. Consistent with our prior work in aqueous systems, applying a current of −100 mA over 8 h yielded sodium levulinate, sodium 4-hydroxyvalerate, sodium acetate, and sodium formate. Confirmation was provided by liquid chromatography electrospray ionization high-resolution mass spectrometry, nuclear magnetic resonance, and infrared spectroscopy. These findings advance our understanding of GVL as a biomass-based platform, highlighting its potential not only for biomass treatment but also as a medium for converting lignin into valuable aliphatic chemicals.

Functions and mechanisms of non-histone protein acetylation in plants.

Lysine acetylation, an evolutionarily conserved post-translational protein modification, is reversibly catalyzed by lysine acetyltransferases and lysine deacetylases. Lysine acetylation, which was first discovered on histones, mainly functions to configure the structure of chromatin and regulate gene transcriptional activity. Over the past decade, with advances in high-resolution mass spectrometry, a vast and growing number of non-histone proteins modified by acetylation in various plant species have been identified. Lysine acetylation of non-histone proteins is widely involved in regulating biological processes in plants such as photosynthesis, energy metabolism, hormone signal transduction and stress responses. Moreover, in plants, lysine acetylation plays crucial roles in regulating enzyme activity, protein stability, protein interaction and subcellular localization. This review summarizes recent progress in our understanding of the biological functions and mechanisms of non-histone protein acetylation in plants. Research prospects in this field are also noted.

Effect of Terminal Phosphate Groups on Collisional Dissociation of RNA Oligonucleotide Anions.

The increasing need for mass spectrometric analysis of RNA molecules calls for a better understanding of their gas-phase fragmentation behaviors. In this study, we investigate the effect of terminal phosphate groups on the fragmentation spectra of RNA oligonucleotides (oligos) using high-resolution mass spectrometry (MS). Negative-ion mode collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD) were carried out on RNA oligos containing a terminal phosphate group on either end, both ends, or neither end. We find that terminal phosphate groups affect the fragmentation behavior of RNA oligos in a way that is dependent on the precursor charge state and the oligo length. Specifically, for precursor ions of RNA oligos of the same sequence, those with 5'- or 3'-phosphate, or both, have a higher charge state distribution and lose the phosphate group(s) in the form of a neutral (H3PO4 or HPO3) or an anion ([H2PO4]- or [PO3]-) upon CID or HCD. Such a neutral or charged loss is most conspicuous for precursor ions of an intermediate charge state, e.g., 3- for 4-nt oligos or 4- and 5- for 8-nt oligos. This decreases the intensity of sequencing ions (a-, a-B, b-, c-, d-, w-, x-, y-, z-ions) and hence is unfavorable for sequencing by CID or HCD. Removal of terminal phosphate groups by calf intestinal alkaline phosphatase improved MS analysis of RNA oligos. Additionally, the intensity of a fragment ion at m/z 158.925, which we identified as a dehydrated pyrophosphate anion ([HP2O6]-), is markedly increased by the presence of a terminal phosphate group. These findings expand the knowledge base necessary for software development for MS analysis of RNA.

Deciphering the complexity of the chemicals in food packaging materials using molecular networks

Chemicals from packaging materials might be transferred into food resulting in consumer exposure. Identifying these migrated chemicals is highly challenging and crucial to perform their safety assessment, usually starting by the understanding of the chemical composition of the packaging material itself. This study explores the use of the Molecular Networking (MN) approach to support identification of the extracted chemicals. Two formulations of bioplastics were analyzed using Liquid Chromatography hyphenated to High-Resolution Mass Spectrometry. Data processing and interpretation using a conventional manual method was performed as a point of comparison to understand the power of MN. Interestingly, only the MN approach facilitated the identification of unknown chemicals belonging to a novel oligomer series containing the azelaic acid monomer. The MN approach provided a faster visualization of chemical families in addition to the highlight of unrelated chemicals enabling to prioritize chemicals for further investigation improving the safety assessment of packaging materials.

Development of intrinsically flame-retardant bio-thermosets with further enhanced thermal stability through a photo-thermal dual polymerization strategy

In response to safety and environmental concerns, there has been a significant increase in research focused on developing high-performance thermoset materials from sustainable sources. In this study, a sophisticated chemical design approach integrates coumarin and furan moieties into a bio-based UV-dimerizable benzoxazine resin. The newly obtained bio-benzoxazine exhibits a reduced curing temperature along with improvements in both thermal stability and flame-retardant properties compared to conventional thermosetting counterparts. Extensive characterization of the chemical structure of the UV-dimerizable bio-based benzoxazine is conducted through nuclear magnetic resonance, Fourier transform infrared spectroscopy, elemental analysis, and high-resolution mass spectrometry. The photo-dimerization processes are monitored using UV–Vis and NMR techniques. Additionally, the thermally activated curing behavior is scrutinized via differential scanning calorimetry and in situ FT-IR techniques. Remarkably, the fully polymerized bio-thermoset demonstrates exceptional thermal stability, possessing a Td10 of 410 °C and a Tg of 283 °C. Moreover, the resulting thermosets also shows very low flammability, as evidenced by a heat release capacity of 14.6 J·g-1·K-1 and a total heat release of 2.97 kJ·g-1. This study not only outlines a method to enhance the overall performance of bio-polybenzoxazines but also provides a direct and sustainable synthesis route for bio-derived, intrinsically non-flammable thermosetting materials.

Organotin(IV) complexes derived from 2,6-diacetylpyridine bis(2-hydroxybenzoylhydrazone) as prospective anti-proliferative agents: Synthesis, characterization, structures and in vitro anticancer activity

Six organotin(IV) complexes, viz., [Me2Sn(L)] (1), [n-Bu2Sn(L)] (2), [n-Oct2Sn(L)] (3), [Bz2Sn(L)]·0.5C7H8 (4), [n-BuSn(L)Cl] (5), and [PhSn(L)Cl] (6), were synthesized using a 2,6-diacetylpyridine bis(2-hydroxybenzoylhydrazone), H2L. Compounds were characterized by Fourier transform infrared (FT-IR), High-resolution mass spectrometry (HRMS), and solutions Fourier transform nuclear magnetic resonance (FT-NMR) spectroscopies. The structures 1–6 were established by single-crystal X-ray diffraction (SC-XRD) analysis. Diffraction results evidenced that complexes 1–6 were seven-coordinated mononuclear species with the equatorial plane comprising the pentagonal N3O2 chelate ring of the doubly deprotonated L and two axial ligands, either R (R = Me, n-Bu, n-Oct, Bz) or R (n-Bu or Ph) and Cl ligands. Additionally, the photophysical properties were examined due to the enhanced conjugation and rigidity of the molecules while thermogravimetric analysis was carried out to evaluate the thermal stabilities of compounds. The anti-proliferative activity of the complexes 1–6 was tested against prostate cancer cells (DU-145) and normal human embryonic kidney cells (HEK-293). Among the compounds, dibutyltin compound 2 exhibited increased anti-proliferative activity, with an IC50 value of 6.16 ± 1.56 μM. The investigation of its mechanism of action involves using AO/EB (acridine orange/ethidium bromide) and ROS (reactive oxygen species) generation assays. This likely detects apoptotic morphological alterations in the nucleus of the cells, with ROS generation ultimately leading to apoptosis and cell death. The superior activity of 2 may be attributed to the C···H contacts and respective higher de outside and di inside distances from the Hirshfeld surface. Thus, these compounds could be a promising alternative to classical chemotherapy agents.

The metabolic response of HepG2 cells to extracellular vesicles derived from Raphanus sativus L. var. caudatus Alef microgreens probed by chemometrics-assisted LC-MS/MS analysis

Extracellular vesicles (EVs) derived from Thai rat-tailed radish (Raphanus sativus L. var. caudatus Alef) microgreens were previously reported as novel bioactive bioparticles against cancer. This study aimed to investigate the metabolic disruption associated with the antiproliferative effect against HepG2 liver cancer cells, a representative of metabolizing cells and tissue. In this study, the neutral red uptake assay was performed to screen for the antiproliferative effect and determine the cytotoxic concentrations of EVs against HepG2 cells. An untargeted approach to cellular metabolomics was conducted using liquid chromatography coupled with the high-resolution mass spectrometry system with multivariate and univariate analyses to determine the metabolic changes of HepG2 liver cancer cells after EV treatment. EVs showed an antiproliferative effect in HepG2 cells with a half-maximal inhibitory concentration (IC50) of 685.5 ± 26.4 and 139.7 ± 4.2 μg/ml at 24 and 48 h, respectively. In the metabolomics study, 163 metabolites were annotated, with 61 significantly altered metabolites. Among these significant metabolites, 18 were related to glycerophospholipid metabolism. Phosphatidylcholine—the important lipid building blocks for cell membranes, lipid mediators for cell proliferation, and immunosuppressive signaling—was mainly decreased by EV treatment. The alteration of cellular phospholipids in cancer was discussed. This finding suggested the possible mechanism of anticancer action of EVs by disrupting phospholipid metabolism and survival signaling in cancer cells. Further studies should be made to confirm EVs' potential as single and combination therapy in vivo to reduce cancer resistance. This may close the gap between in vitro study and clinical setting.

Staphylococcal Enterotoxins: Description and Importance in Food.

Staphylococcus aureus stands out as one of the most virulent pathogens in the genus Staphylococcus. This characteristic is due to its ability to produce a wide variety of staphylococcal enterotoxins (SEs) and exotoxins, which in turn can cause staphylococcal food poisoning (SFP), clinical syndromes such as skin infections, inflammation, pneumonia, and sepsis, in addition to being associated with the development of inflammation in the mammary glands of dairy cattle, which results in chronic mastitis and cell necrosis. SEs are small globular proteins that combine superantigenic and emetic activities; they are resistant to heat, low temperatures, and proteolytic enzymes and are tolerant to a wide pH range. More than 24 SE genes have been well described (SEA-SEE, SEG, SEH, SEI, SEJ, SElK, SElL, SElM, SElN, SElO, SElP, SElQ, SElR, SElS, SElT, SElU, SElV, SElW, SElX, SElY, and SElZ), being a part of different SFP outbreaks, clinical cases, and isolated animal strains. In recent years, new genes (sel26, sel27, sel28, sel31, sel32, and sel33) from SEs have been described, as well as two variants (seh-2p and ses-3p) resulting in a total of thirty-three genes from Ses, including the nine variants that are still in the process of genetic and molecular structure evaluation. SEs are encoded by genes that are located in mobile genetic elements, such as plasmids, prophages, pathogenicity islands, and the enterotoxin gene cluster (egc), and housed in the genomic island of S. aureus. Both classical SEs and SE-like toxins (SEls) share phylogenetic relationships, structure, function, and sequence homology, which are characteristics for the production of new SEs through recombination processes. Due to the epidemiological importance of SEs, their rapid assessment and detection have been crucial for food security and public health; for this reason, different methods of identification of SEs have been developed, such as liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS), molecular methods, and whole-genome sequencing; providing the diagnosis of SEs and a better understanding of the occurrence, spread, and eradication of SEs. This review provides scientific information on the enterotoxins produced by S. aureus, such as structural characteristics, genetic organization, regulatory mechanisms, superantigen activity, mechanisms of action used by SEs at the time of interaction with the immune system, methods of detection of SEs, and recent biocontrol techniques used in food.

Gas Phase Aldehydes Detection in Exhaled Breath in Screening of Barrett's Esophagus

Aldehydes, e.g., acetaldehyde, have been classified as toxic and carcinogenic volatile organic compounds (VOCs) and are recognized as one determinant of upper aerodigestive tract cancer like Barrett's esophagus. Measuring aldehyde levels in breath provides information about the aldehydes released by abnormal cells, the level of aldehyde dehydrogenase (ALDH2) activity, and risks and diseases associated with high levels of acetaldehyde, which include liver disease and lung and upper digestive cancers. Devices currently available for breath analysis are state-of-the-art, high-resolution mass spectrometry instruments. These instruments have some drawbacks such as size, initial cost, and operational expense. Electrochemical sensors are capable of miniaturization and are available as portable and handheld breathalyzers. The non-invasive nature of breath analysis and its easy sampling makes smaller devices a more attractive alternative, particularly for continuous monitoring and point-of-care (POC) testing.1 However, the lack of an exchangeable/disposable sensing element, the resulting memory effect, and the need for frequent recalibration is the main drawback of currently available electrochemical breathalyzers.Herein we examine the feasibility of a POC testing device for aldehyde in exhaled breath to assess the medical application of such a device in noninvasive diagnostic testing for Barrett’s esophagus. To improve the selectivity of the method we harness the unique catalytic activity of the aminoxyl radical/oxoammonium redox couple toward aldehyde oxidation. The highly selective/sensitive device offers the capability for use in the detection of Barrett's esophagus, ideally at early stages, without the need for a high-cost screening test. Our functional sensing element consists of a screen-printed electrode (SPE) in which the graphene oxide-based is the working electrode. Exposing this electrode to simulated breath that contains aldehyde, while applying the required potential for oxidation of the aminoxyl radical (4-acetamido-TEMPO known as ACT), generates an electrocatalytic current proportional to the aldehyde concentration in the breath. These simple, sensitive, durable, and inexpensive electrodes may contribute to the development of a single-use reliable aldehyde sensor for personal or law enforcement applications.1. M. Mayer, M. Rafiee, Electrocatalytic Detection of Ethanol and Acetaldehyde by Aminoxyl Radicals: Utilizing Molecular Catalysis for Breath Analysis. Analyst 147, 2022, 3420 – 3423.

Prevalence of perfluoroalkyl substances in paired batches of precooked and canned bovine meat and their implication on consumer safety

Meat is a highly nutritious food but there is a lot of significant evidence of negative health outcomes related to its excessive consumption, especially for processed one. Among the variety of emerging contaminants of concern for human health, a key role is played by poly- and per-fluoroalkyl substances (PFASs), which show adverse effects in humans who are exposed to them through diet. In the present study, for the first time, 70 paired batches of pre-cooked and canned bovine meat were analysed by Liquid Chromatography coupled to High Resolution Mass Spectrometry to evaluate the presence and concentration of 18 PFASs. These data were used to assess Italian consumers’ health risks by performing the PFAS intake evaluation. PFBA and PFOS were detected in the precooked and canned meat samples, with PFBA mean concentration of 0.22 ± 0.36 ng g−1, and <LOQ, respectively, and PFOS mean concentration of <LOQ in both. No PFASs were found in the jelly. The comparison between the PFBA levels in precooked and canned meat showed a significant difference. The PFAS intake evaluation showed an Estimated Daily Intake by far lower than the Tolerable Daily Intake for the average Italian consumer suggested by the European Food Safety Authority.

Production of Lactic Acid via Catalytic Transfer Dehydrogenation of Glycerol Catalyzed by Base Metal Salt Ferrous Chloride and Its NNN Pincer-Iron Complexes.

NNN-Bis(imino) pyridine-based pincer-Fe(II) complexes with an expected trigonal bipyramidal (TBP) geometry equilibrated to a rearranged ion pair of an octahedral dicationic Fe complex containing two bis(imino)pyridine ligands that are neutralized by a tetrahedral dianionic-[FeCl4]2-. Single-crystal X-ray diffraction (SCXRD), high-resolution mass spectrometry (HRMS), and UV-visible (UV-vis) studies suggested that the equilibrium was dictated by the sterics of the R group on the imine N, with the less-crowded groups tilting the equilibrium to the ion pair and the bulky ones favoring the TBP geometry. Electron paramagnetic resonance (EPR) and Evan's magnetic moment measurements indicated that the complexes were paramagnetic with Fe(II) in a high-spin state. In solution, over a period of 7 days, these Fe(II) complexes oxidized to a mixture of low-spin and high-spin Fe(III) species. These pincer-Fe(II) were found to be highly active toward the transformation of biodiesel waste glycerol to value-added lactic acid (LA). Particularly, (Ph2NNN)FeCl2 (0.1 mol %) gave 91% LA with a 99% selectivity at 140 °C using 1.2 equiv of NaOH. With 0.0001 mol % (Ph2NNN)FeCl2, very high turnovers (74% LA, 98% selectivity, 740 000 turnover number (TON) at 4405 turnovers per hour (TOs/h)) were obtained after 7 days. EPR indicated Fe(III) species to be the active catalyst, a few of which were detected by HRMS. Experiments with Hg are suggestive of the mostly homogeneous molecular nature of the catalyst with a minor contribution from heterogeneous Fe nanoparticles.