High-resolution Mass Spectrometry Research Articles

Prioritizing Chemical Features in Non-targeted Analysis through Spatial Trend Analysis: Application to the Identification of Organic Chemicals Subject to Mountain Cold-Trapping.

One of the challenges arising during non-targeted analysis (NTA) is that the number of detected chemical features is generally too large for detailed processing and interpretation. Here, we illustrate how the analysis of spatial trends in peak intensities can be an effective tool to prioritize chemical features in NTA. Specifically, features detected by gas chromatography and high-resolution mass spectrometry in soil and air samples, collected along an altitudinal transect on an urban mountain in Canada, were successfully grouped into different categories based on spatial trends with site altitude. The motivation was to identify features whose abundance increases in soil with increasing elevation, as the ability for amplification at higher elevations could characterize contaminants of concern to mountain ecosystems. Potential matching candidates were first selected by comparing empirically detected accurate masses and isotope distributions of chemical features with those in chemical databases. These potential candidates were then ranked by comparing MSMS spectra with fragments predicted in silico. Several highly ranked matches, as well as structurally related compounds, which were largely halogenated methoxylated benzenes and organochlorine pesticides, were then subjected to targeted analysis with analytical standards. Several of these compounds, including pentachloroanisole, tricamba, and 3,4,5-trichloroveratrole, were identified as having spatial patterns consistent with mountain cold-trapping, as evidenced by organic carbon-normalized soil concentrations that show a significant increase with elevation. Our study clearly demonstrated that spatial trend analysis holds considerable promise as a tool to guide chemical identification and prioritization during NTA.

First Confirmed Occurrence of Ciguatera Poisoning in the UK from Imported Pinjalo Snapper (Pinjalo pinjalo)

Three people in England consumed fish steaks labeled as Red Snapper (Lutjanus bohar) originating from the Indian Ocean. Within 12 h, all three experienced sickness including nausea, vomiting, diarrhea, as well as myalgia and paresthesia. Three steaks from a single package of fish obtained from a grocery store were consumed, leaving one uneaten, which was submitted for analysis. Cytotoxicity testing via the mouse neuroblastoma assay confirmed the presence of sodium channel specific activity consistent with a ciguatoxin standard, and the levels detected were above established guidance limits for safe consumption. Chemical detection using liquid chromatography coupled with high-resolution mass spectrometry of both intact toxins and periodate oxidation products was used to confirm the presence of chromatographic peaks consistent with tri- and di-hydroxylated Pacific ciguatoxin 3C congeners. Taking the shared medical symptoms of patients, the recent dietary history, and the known potential for ciguatera poisoning to occur in snapper species, the subsequent evidence for CTX-like activity and CTXs in the same fish sample provides very strong evidence that the fish steaks consumed were similarly contaminated with CTXs. Furthermore, given the levels reported, such toxicity would be expected to cause intoxication in humans. Fish species identification based on DNA barcoding confirmed that the fish products were mislabeled, with the tissues instead being the Pinjalo snapper, Pinjalo pinjalo. This is the first confirmed ciguatera poisoning incident in both the UK and from the Pinjalo snapper and highlights the need for monitoring of these emerging toxins in reef fish imports to prevent future human intoxication.

Synthesis and Characterization of Benzo[1,2-b:4,3-b’]dithiophene-Based Biaryls

The synthesis of three biaryl systems containing the benzo[1,2-b:4,3-b’] framework was accomplished through the Suzuki–Miyaura cross-coupling reaction between 1-bromobenzo[1,2-b:4,3-b’]dithiophene and easily available polycyclic aromatic hydrocarbon boronic acid pinacol esters containing pyrene, fluorene, and fluorenone. The spectroscopic characterization of these molecules was carried out by means of NMR experiments and high-resolution mass spectrometry. UV-vis absorption measurements at different concentrations of the newly synthesized compounds were also performed.

Lanthanide Molecular Clusters and Metal-Organic Layers Constructed by Manipulation of Substituents.

Usually, complexes with different connections and shapes are constructed by regulating the substituents. However, it is extremely challenging to construct two lanthanide complexes with different dimensions by only fine-tuning the substituents of the ligands, especially the substituents (-CH3 and -CH2CH3) with almost similar physical and chemical properties. Herein, by only regulating the substituents of the multidentate chelating ligands, two lanthanide complexes with different dimensions and connection modes were successfully constructed using a multicomponent "one-pot method" under the guidance of the multidentate chelating coordination method (MCC). They are the 11-nuclear lanthanide molecular cluster (Dy11) and the metal-organic layer (2D-Dy). Specifically, when the selected ligand is an imidazole-2-carboxaldehyde derivative and its substituent is -CH3, a layered 2D-Dy is obtained. The linker [Dy(HL1)3] with a propeller configuration is formed by chelating the Dy(III) ion with an acylhydrazone ligand (HL1) formed by the condensation of three salicylhydrazides and 1-methyl-1H-imidazole-2-carboxaldehyde. The above linkers were further linked alternately with propeller-shaped [Dy(NO3)3] as a secondary building unit (SBU) to form 2D-Dy. In addition, by changing the -CH3 on the ligand to -CH2CH3, we obtained an example of Dy11 formed by epitaxial assembly of two Dy(III) ions with an hourglass-shaped Dy9 as the core, and its molecular formula is [Dy11(HL2)8(μ3-OH)8(μ4-O)2(CH3O)4(NO3)4](NO3)5 18CH3OH. The cluster Dy11 was bombarded using high-resolution electrospray ionization mass spectrometry (HRESI-MS) and the molecular ion peaks of various fragments formed were captured. Based on the above molecular ion peaks, the possible fragmentation mechanisms of Dy11 were inferred to be Dy11 → Dy4(HL2)4 → Dy3(HL2)2 → Dy2(HL2)2 → Dy(HL2)2 and Dy11 → Dy(HL2)2/Dy2(HL2)2/Dy3(HL2)2/Dy4(HL2)4. This work is one of the rare examples where fine-tuning of ligand substituents leads to the formation of complexes of different dimensions, which promotes the progress of crystal engineering of lanthanide complexes.

Naturally occurring indole-3-acetic acid in foods: a need for review of the current risk management measures in the EU

Indole-3-acetic acid (IAA) is a natural plant hormone which can also be used as a plant growth regulator. However, its usage on crops is not permitted in the EU, with a maximum residue limit (MRL) currently set at 0.1 mg kg−1 for all food commodities. As available data on the occurrence of IAA in food commodities are limited, this work aims at evaluating the amount of IAA in important food commodities such as coffee and cereals, but also selected processed ingredients such as cocoa and malt. In total, 133 samples representing 18 different food commodities were analysed for the occurrence of free IAA using a liquid chromatography high resolution mass spectrometry method. IAA was detected in all samples except malt powders and tomatoes. The analysed crops were either grown under conventional, organic, or strictly controlled (i.e. excluding the use of IAA as pesticide/plant growth regulator) farming conditions. No significant differences in the amounts of IAA were found in crops grown under the three different farming conditions. A high percentage of the samples (63%) showed levels of free IAA above the EU MRL. We therefore conclude that the natural abundance of IAA was not properly assessed prior to the establishment of some current EU MRLs. Based on the natural occurrence of IAA in a wide range of foods; we question the need for an MRL for IAA in plant-based foods.

Screening Refractory Dye Degradation by Different Advanced Oxidation Processes

This study investigated Rhodamine B (RhB) degradation by electro-Fenton (EF), anodic oxidation (AO), and their combination (EF/AO), using a carbon felt cathode coupled to a sub-stoichiometric titanium dioxide Magnéli phase (Ti4O7) anode or a platinized titanium (Ti/Pt) anode. The results indicated that operational parameters influenced the kinetics of electrochemical reactions. An increase in current density from 10 to 50 mA cm−2 significantly enhanced the RhB degradation rate; 30 mA cm−2 was the optimal current density, balancing both energy efficiency and degradation performance. Moreover, higher RhB concentrations required longer treatment. The Microtox® bioluminescence inhibition test revealed a significant toxicity decrease of the dye solution during electrochemical degradation, which was highest with EF/AO. Similarly, total organic carbon removal was highest with EF/AO (90% at pH 3), suggesting more efficient mineralization of RhB and its by-products than with EF or AO. Energy consumption remained relatively stable with all oxidation processes throughout the 480 min electrolysis period. High-resolution mass spectrometry elucidated RhB degradation pathways, highlighting chain oxidation reactions leading to the formation of intermediates and mineralization to CO2 and H2O. This study underscores the potential of EF, AO, and EF/AO as effective methods for RhB mineralization to develop sustainable and environmentally friendly wastewater treatment strategies.

Pharmacophore Recombination Design, Synthesis, and Bioactivity of Ester-Substituted Pyrazole Purine Derivatives as Herbicide Safeners.

Mesosulfuron-methyl, an acetolactate synthase (ALS) inhibitor primarily applied to wheat and rye, can injure or even kill wheat crops. Herbicide safeners can improve the herbicide resistance of crops without reducing the herbicidal effect on targeted weed species. Herein, we present a series of pyrazole purine derivatives with the primary structure of the natural product cytokinin and commercialized safener mefenpyridyl, designed using the pharmacophore recombination method. The title compounds were synthesized and characterized using infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy, and high-resolution mass spectrometry. A bioactivity assay proved that most of the target compounds can reduce the wheat phytotoxicity of mesosulfuron-methyl. Measurements of chlorophyll and glutathione contents, along with other enzyme activity assays, confirmed that compounds I-15 and I-13 exhibit higher safety activities compared with the mefenpyr-diethyl safener. Molecular structure comparisons demonstrated that I-15 is more readily absorbed and disseminated through the crop than the commercialized safener mefenpyr-diethyl. Molecular docking models and molecular dynamics simulations elucidated the protective mechanism of safeners; specifically, compound I-15 competitively binds to the ALS active site with mesosulfuron-methyl. The current study reveals the potential of pyrazole purine derivatives in the future discovery of novel herbicide safeners.

Influence of counterion substitution on the properties of imidazolium-based ionic liquid clusters.

Due to their unique physiochemical properties that may be tailored for specific purposes, ionic liquids (ILs) have been investigated for various applications, including chemical separations, catalysis, energy storage, and space propulsion. The different cations and anions comprising ILs may be selected to optimize a range of desired properties, such as thermal stability, ionic conductivity, and volatility, leading to the designation of certain ILs as designer "green" solvents. The effect of counterions on the properties of ILs is of both fundamental scientific interest and technological importance. Herein, we report a systematic experimental and theoretical investigation of the size, charge, stability toward dissociation, and geometric/electronic structure of 1-ethyl-3-methyl imidazolium (EMIM)-based IL clusters containing two different atomic counterions (i.e., bromide [Br-] and iodide [I-]). This work extends our studies of EMIM+ cations with atomic chloride (Cl-) and molecular tetrafluoroborate (BF4-) anions reported previously by Baxter et al. [Chem. Mater. 34, 2612 (2022)] and Zhang et al. [J. Phys. Chem. Lett. 11, 6844 (2020)], respectively. Distributions of anionic IL clusters were generated in the gas phase using electrospray ionization and characterized by high mass resolution mass spectrometry, energy-resolved collision-induced dissociation, and negative ion photoelectron spectroscopy experiments. The experimental results reveal anion-dependent trends in the size distribution, relative abundance, ionic charge state, stability toward dissociation, and electron binding energies of the IL clusters. Complementary global optimization theory provides molecular-level insights into the bonding and electronic structure of a selected subset of clusters, including their low energy structures and electrostatic potential maps, and how these fundamental characteristics are influenced by anion substitution. Collectively, our findings demonstrate how the fundamental properties of ILs, which determine their suitability for many applications, may be tuned by substituting counterions. These observations are critical in the sub-nanometer cluster size regime where phenomena do not scale predictably to the bulk phase, and each atom counts toward determining behavior.

Mechanistic insights into the anticancer, anti-inflammatory, and antioxidant effects of yellowfin tuna collagen peptides using network pharmacology

Marine-derived collagen peptides have been acknowledged for their therapeutic potential, especially in cancer therapy and inflammation management. The aim of this study was to investigate the molecular mechanisms that contribute to the anticancer, anti-inflammatory and antioxidant properties of yellowfin tuna collagen peptides (YFTCP) utilizing a network pharmacology approach. The YFTCP was extracted from the bones of yellowfin tuna (Thunnus albacares) and subsequently hydrolyzed with trypsin. Seventeen peptides were discovered using liquid chromatography in conjunction with high-resolution mass spectrometry (LC-HRMS). A network pharmacology method was utilized to investigate the interactions between the discovered peptides and their biological targets. Additionally, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to identify pertinent biological pathways involved in the anticancer, antioxidant, and anti-inflammatory effects of these peptides. GO analysis revealed key associations between YFTCP and critical cancer- and inflammation-related genes encoding proteins such as CCND1, SRC, AKT1, IL-1β, TNF, and PPARG, which exhibited significant interactions. These proteins are essential for the regulation of the cell cycle, the development of tumors, and the response to inflammatory stimuli. The KEGG analysis also revealed that YFTCP was involved in a number of critical pathways, such as endocrine resistance, cancer pathways, Kaposi sarcoma-associated herpesvirus infection, proteoglycans in cancer, and human cytomegalovirus infection. These findings highlight the potential use of YFTCP as a multifaceted therapeutic agent, indicating their role in regulating important biological pathways associated with cancer development and inflammation. This study provides new valuable insights into the pharmacological properties of YFTCP, paving the way for future studies and drug development focused on these bioactive peptides.

Near Ambient Condition Ammonia Synthesis and In-Situ CO2 Co-Reduction to Urea from Nitrate.

Herein, conversion of nitrate (NO3̅) to ammonia (NH3) up to ∼100 mM and in-situ cascade CO2 co-reduction to urea (up to ∼1.36 mM) has been demonstrated by thermally activated hydrogen peroxide (H2O2) at near ambient conditions (∼100 °C). NH3 synthesis from NO3̅ has been confirmed using absorption, 1H nuclear magnetic resonance (NMR) analysis of the reduced product and 15N isotopic labeled nitratre (15NO3̅) experiement. The results associated with the urea synthesis have been verified using absorption, 1H NMR, and high resolution-mass spectrometry (HR-MS) analysis.

Convolutional Neural Networks Assisted Peak Classification in Targeted LC-HRMS/MS for Equine Doping Control Screening Analyses.

Doping control screening analyses usually involve visual inspection of extracted ion chromatograms (EIC) by a trained analytical chemist, followed by further investigations if needed. This task is both highly repetitive and time-consuming, given the hundreds of compounds and metabolites to be screened in tens of thousands of samples per year. With the recent widespread adoption of machine learning in analytical chemistry and the training of high-performance convolutional neural networks (CNN), these operations can be automated with high accuracy and throughput. Applying this technology to doping control is challenging as the false negative rate (FNR) shall be equal to zero. In this study, we demonstrated that implementing a deep learning strategy for chromatogram classification in equine doping control can be feasible and accurate. We illustrated our findings with a CNN scoring model combined with a linear discriminant analysis (LDA) classifier trained on chromatogram images from our ultra-high-pressure liquid chromatography coupled to high-resolution tandem mass spectrometry (UHPLC-HRMS/MS)-based biotherapeutics screening method. We expect that artificial intelligence (AI) will be a valuable tool for doping control laboratories in the near future.

Quantitative Analysis of Neuropeptide Y (NPY) and C-Terminal Glycine-Extended NPY by Mass Spectrometry and Their Localization in the Developing and Sexual Adult Mouse Brains.

Neuropeptide Y (NPY), a central stimulator of food intake and an energy balance controlling hormone, was quantitatively analyzed in developing brains at birth using microflow liquid chromatography (LC) and triple-quadrupole tandem mass spectrometry (MS/MS). We detected and identified endogenous C-terminal glycine-extended NPY (NPY-Gly 1-37) first, an intermediate of NPY before amidation in the mouse brain using high-resolution Fourier-transform Orbitrap MS and MS/MS. NPY-Gly was present in the fetal brain (E16) at almost the same levels as NPY of 1.92 pmol/g-brain tissue. After birth, NPY in postnatal 2-day brains (P2) was elevated drastically at 11.02 pmol/g-brain (p < 0.05 vs E16) and remained at a high level for the first 10 postnatal days, an important period for the formation of the NPY neural circuit in the brain. Immunohistochemistry unexpectedly showed that the localizations of NPY and NPY-Gly in the hypothalamus were completely different: NPY was localized in the arcuate nucleus, whereas NPY-Gly was already located at pars tuberalis during brain development from a fetus to a neonate to a sexual adult.

Discovery of Dual ROCK1/2 Inhibitors from Nocardiopsis sp. under Metal Stress.

Rho-associated protein kinase (ROCK) inhibitors are promising therapeutic agents for reducing elevated intraocular pressure in patients with glaucoma. We explored new ROCK inhibitors derived from bioactive metabolites produced by microbes, specifically cryptic metabolites from Nocardiopsis sp. MCY7, using a liquid chromatography-mass spectrometry-based chemical analysis approach integrated with metal stress-driven isolation. This strategy led to the identification of two previously undescribed linear peptides, nocarnickelamides A and B (1 and 2), and an unreported cittilin derivative, cittilin C (3). The planar structures of 1-3 were elucidated using UV spectroscopy, high-resolution mass spectrometry, and nuclear magnetic resonance. The absolute configurations of 1 and 2 were assigned using the advanced Marfey's method. Biological assays demonstrated that nocarnickelamides (1 and 2) exhibited dual inhibitory activity against ROCK1 (IC50 29.8 and 14.9 μM, respectively) and ROCK2 (IC50 27.0 and 21.9 μM, respectively), with molecular simulations suggesting binding to the ATP-binding site. In human trabecular meshwork cells, 2 significantly inhibited the activation of ROCK-regulated cytoskeletal contraction markers such as the myosin light chain. Nocarnickelamide B (2) is a novel dual ROCK1/2 inhibitor and a potential pharmacophore for designing new therapeutic agents to reduce intraocular pressure in glaucoma.

NIR Fluorescence Strategy for the Early Diagnosis of Melanoma Liver Metastasis Based on the Cascade Reaction of Two Specific Bioenzymes.

Melanoma liver metastasis poses a serious risk to patient health, leading to deterioration of liver function accompanied by symptoms such as jaundice, abdominal pain, and weight loss. Early detection is paramount as it allows for timely intervention, potentially improving treatment efficacy and patient outcomes. Herein, a dual-target probe activated by butyrylcholinesterase (BChE) and tyrosinase (TYR) was proposed by initiating an enzyme cascade reaction, revealing NIR-emissive methylene blue (MB) as a responsive product. The cascade reaction mechanism was confirmed by enzyme activity inhibition experiments and high-resolution mass spectrometry. Intercellular imaging was carried out on the coincubation model of Hep G2 and B16 cell lines, which is the first attempt to the best of our knowledge. The results showed that BChE expressed in liver cells and TYR overexpressed in B16 cells jointly activated NIR fluorescence, which provides the possibility for the precise detection of melanoma liver metastasis. In vivo studies further proved that this method holds promise for the early diagnosis and postoperative adjunctive therapy of hepatic melanoma, ultimately enhancing survival rates.

Investigation of Impurities in Peptide Pools

Peptide pools are important research tools in different biomedical fields. They consist of a complex mixture of defined peptides, which places high demands on the production and quality control of these products. Previously it has been shown that the combination of UHPLC with high-resolution mass-spectrometry (HRMS) is a fast and powerful method to confirm the relative concentration and the structural identity of all peptides expected to be in the pool. In this work, the additional information contained in the UV chromatograms and mass spectra is used to search for impurities due to synthesis by-products and degradation during storage and transportation and to identify possible analytical artifacts. It was shown that most impurities are only present in trace amounts and can be considered uncritical for most applications. The most frequent and perhaps unexpected impurities were homo- and heterodimers caused by the free cysteines contained in these peptide pools. Furthermore, pyroglutamate and aspartimide formation, deamidation, methionine oxidation, and amino acid deletions could be found. This list is not intended to be comprehensive, but rather a brief guide to quickly identify impurities and, in the long term, to suggest possible changes in the composition of the peptide pools to avoid such impurities by design or by special precautions.

The single-berry metabolomic clock paradigm reveals new stages and metabolic switches during grapevine berry development.

Asynchronicity causes metabolic chimerism in usual grapevine phenological stages, calling for a revisit of berry development at the individual fruit scale. To reveal the dynamics of metabolite composition in grapevine berries without phenological a priori, a dataset of 9,256 ions was obtained on 125 fruits at different stages by non-targeted ultra-performance liquid chromatography coupled to high-resolution mass spectrometry. This large metabolomic dataset was submitted to an analysis workflow combining classification and dimension reduction tools. This led to the clustering of metabolites into 12 specific kinetic patterns and a metabolome-based definition of the pericarp intrinsic clock outperforming expert timing procedures. Such increased temporal resolution enabled the identification of metabolite clusters that are annunciative of the onset of ripening, noticeably characterized by transient lipidic changes and the start of ABA accumulation. We also highlighted a cluster of stilbenes that accumulate during terminal fruit shriveling, after the arrest of phloem unloading. This non-targeted approach enables a more precise characterization of grapevine berry development through the concept of metabolomic clock. The discovery of new metabolic milestones of berry development paves the way toward a better assessment of the impact of environmental changes on the metabolism of non-climacteric fruit, in different genotypes.

High-throughput screening to identify endocrine disruptors: Contribution of low-resolution tandem MS and high-resolution MS.

Considering the large diversity of chemicals present in the environment and the need to study their effects (alone or as mixtures), the development of high-throughput in vitro assays in line with the Replacement, Reduction, Refinement (3R) strategy is essential for chemical risk assessments. We developed a robust analytical workflow based on both low resolution tandem mass spectrometry (MS/MS) and high-resolution mass spectrometry (HRMS) to quantify 13 steroids in NCI-H295R cell culture medium, human plasma and serum. The workflow was validated by screening media from the NCI-H295R cell line exposed in dose-response experiments to 5 endocrine disruptors (EDs) such as bisphenol A, prochloraz, ketoconazole, atrazine and forskolin. Absolute quantifications of the 13 steroids performed on a triple quadrupole (QqQ) MS/MS demonstrated that the performances obtained were in line with OECD recommendations. HRMS (MS1-HRMS) provided measurements nearly as sensitive and as reproducible as those obtained using multiple reaction monitoring (MRM) and ELISA. A bioinformatics workflow, using HRMS, was implemented to detect and annotate disrupted metabolites. HRMS allowed to detect disruptions in pathways associated to fatty acids, purines and amino acids metabolisms after exposure to the EDs tested, in addition to that linked to steroidogenesis. We developed a robust MS1-HRMS workflow, from sample preparation to compound quantification or annotation, compatible with absolute steroid quantification, to screen NCI-H295R cell media exposed to potential EDs. Using only 200μL of medium, the method integrates MS/MS and HRMS analyses, 96-well plate solid-phase extraction for high throughput, and automated pre-annotation for cost efficiency. This optimized workflow identifies EDs in cell assays by detecting disruptions in steroidogenesis and other biological pathways.

A cyanobacterial outbreak in Lake Avernus: Targeted and untargeted analyses and follow up actions for food safety.

A massive Planktothrix rubescens bloom was observed during 2022 in the Lake Avernus, a volcanic lake located in Campania Region (Southern Italy). The cyanobacterial mass migrated, through a channel, to the near Gulf of Pozzuoli, causing the contamination of two marine sites dedicated to mussel farming, thus posing a potential risk for consumers' health. Mussel and water samples, from both the sea and the lake were collected weekly and analyzed by liquid chromatography coupled to tandem mass spectrometry, for identification and quantification of 10 microcystins. Moreover, the samples were analyzed by high resolution mass spectrometry in untargeted mode to determine other cyanotoxins basing on the accurate mass of the precursor ions and their MS/MS spectra. The microcystins were not detected at all, whereas other bioactive peptides, such as anabaenopeptins and oscillamide Y, were detected according to the toxicological profiles described for Planktothrix rubescens in the scientific literature. The case reported represents a modern approach for rapid characterization of some environmental outbreaks, as well as an example regarding how the public Health Authority can manage the possible risk for food safety, due to unknown substances and to enforce legal follow up actions.

Decoding historical and emerging environmental concerns of C6−36 chlorinated paraffins: Insights from marine sediment cores in the Pearl River Estuary

Chlorinated paraffins (CPs) readily deposit in sediments upon entering estuaries and adjacent seas. Time-series investigations are indispensable for the long-term monitoring of historical releases and identifying CPs of emerging concerns in the marine environment. In this study, short-, medium-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) were investigated using time-of-flight high-resolution mass spectrometry (ToF-HRMS) in sediment cores, dated between the 1920s and the 2010s sampled from Hong Kong waters and Lingdingyang of the Pearl River Estuary (PRE), South China. Levels of SCCPs remained steady since the 1980s, while increasing trends of MCCPs and LCCPs were observed, indicating a market supply shift from SCCPs to MCCPs and LCCPs, potentially influenced by global restrictions. This is the first study to report C18−31 CPs in Chinese marine sediments. C>20 very long-chain CPs (C>20 vLCCPs) subcategorized from LCCPs semi-quantified via ToF-HRMS positively correlated with those of other CP categories, implying their synchronized release in the investigated regions. C>20 vLCCPs, contributing an average of 27% of total CP concentrations in two cores, were found at higher levels than LCCPs (7%). Hence, the risk of C>20 vLCCP contamination should not be ignored. By highlighting the temporal variations in the world’s largest producer and consumer of CPs, the present study augments the database of the continuous deposition of SCCPs and MCCPs in marine sediments in the PRE and highlights the unrecognized risks of LCCP contaminations.

Alkaloid profile of Italian alpine milk.

This study examines the alkaloid profiles in alpine milk. Alkaloids could pose a health concern but also prove interesting from a geographic traceability perspective. Over three consecutive days, 48 daily milk samples were collected from 16 lactating cows grazing on two alpine pastures in Northeast Italy, with 8 cows from each pasture. Simultaneously, alpine herbs selecting by the cows during grazing were collected using the hand-plucking technique. Additionally, 12 milk mass samples were obtained from an entire herd of 110 cows. Liquid chromatography coupled with high-resolution mass spectrometry was employed to analyze both herbage and milk samples, identifying 41 alkaloids with pure standards and putatively identifying another 116. The results revealed a transfer of 0.4% for pyrrolizidine alkaloids, 2.7% for indole alkaloids, and 12% for steroidal alkaloids from herbs to milk. A partial least squares-discriminant analysis model based on the alkaloid profiles achieved a correct reclassification of 67% of milk samples from cows grazing on the two distinct pastures. Despite the minimal transfer, which should be considered positive in terms of health, it opens the door to interesting studies on the use of alkaloids as traceability markers for mountain products. PRACTICAL APPLICATION: The study provides a novel perspective interaction between alpine grazing systems and milk composition. This research could be useful for enhancing mountain pasture products in terms of healthiness and can help prevent fraud on the declaration of origin.