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L’objectif général de ce travail de fin d’études était d’améliorer la méthode de dosage de trace d’hormones naturelles (E1, E2 et E3) et synthétique (EE2). Cette méthode a été développée par Alex Glineur (2016). Cette méthode de dosage UPLC-MS/MS a tout d’abord été testée sur trois types d’échantillon d’eau soigneusement choisis (eaux de surface et eau souterraine). Les performances de la méthode ainsi que les voies d’amélioration ont été étudiées. L’ajout d’une étape SPE de clean-up ainsi que l’utilisation d’une phase stationnaire alternative (UPLC) ont été déterminés comme axes principaux d’amélioration de la méthode.
L’étude ainsi que la résolution de la problématique importante de la suppression d’ionisation ont également constitué un point important de ce travail. En effet, ce phénomène est observé de manière récurrente sur des échantillons d’eau en MS (/MS) mode electrospray (ESI). L’ajout de la cartouche à caractéristiques polaires Florisil ainsi que l’utilisation de la colonne chromatographique Biphényl ont permis de supprimer drastiquement l’effet de suppression d’ionisation tout en garantissant des rendements acceptables. La séparation de l’éluat de la cartouche Florisil en deux fractions (E1+E2+EE2 et E3) s’est avérée essentielle pour associer rendement important et limitation remarquable de la suppression d’ionisation.
La méthode présentée par Alex Glineur ne permettait pas encore d’identifier et quantifier l’17-α ethynylestradiol à la valeur de LOQ recommandée par la Commission Européenne dans des eaux (suspectées) d’être contaminées (proche de 0,1 ng/L). La confirmation même de la présence de cette molécule était impossible à de très faibles concentrations (proches de 0,1 ng/L). En effet, les ratios des qualifiers liés à des fragments très à très peu spécifiques étaient tous biens supérieurs à leur intervalle de confiance de valeurs. Des interférences présentes dans la matrice Sambre (matrice de référence) perturbaient l’analyse d’EE2 et la méthode améliorée a montré son efficacité en offrant des ratios corrects pour la majorité des qualifiers. Cette capacité à identifier et à quantifier EE2 naturellement présent à des valeurs autour du dixième de ng/L a été confirmée par l’analyse de la Haine (Hensies).
La méthode finale présentée est capable de répondre aux récentes exigences de la Commission Européenne en termes de LOQ en ce qui concerne les trois estrogènes que cette dernière a ciblés (E1, E2 et EE2). La validation de cette méthode est l’ultime étape avant sa possible utilisation en routine.

Estrogens - LC-MS/MS - Water --- Ingénierie, informatique & technologie > Ingénierie chimique

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Glyphosate (N-(phosphonomethyl)glycine) is the most used herbicide worldwide. It exhibits all the advantages of the perfect herbicide : it is universal in the way it targets an enzyme present in all plants as well as algae and numerous microorganisms; but not animals, making its acute toxicity very low for human and fauna, its mobility in soil has long been regarded as negligible, it is degraded by UV light (including sunlight) and bacteria commonly found in soils, it allows to limit ploughing and thus to promote soil conservation by reducing erosion; and, above all, it also has the tremendous advantage to spare genetically modified resistant crops, providing a huge financial benefits and allowing to reduce the use of other more toxic herbicides as well as the carbon footprint through reduced use of agricultural machinery.
However, the decades-long debate on its carcinogenicity has been reignited in 2015 when the International Agency for Research on Cancer classified glyphosate as “possibly carcinogenic to humans” (category 2A). The chronic effects of glyphosate and its main metabolite, aminomethylphosphonic acid (AMPA), (i.e. carcinogenicity, mutagenicity, endocrine disruptor potency...) are a real concern knowing that glyphosate is so widely used that the two contaminants , and mostly the more mobile AMPA, has been shown to reach water tables and to become ubiquitous in soils, water streams and sewage. Indeed, the molecule has been shown to be quite persistent in water and soils in a certain number of conditions of composition, weather and bacterial communities. Glyphosate metabolization in plants is vastly recognized as low or negligible, which suggest that genetically modified resistant crops might thus accumulate the herbicide until consumption. Finally, a few studies and even instances of the World Health Organization have been starting to suggest that the negative effects of glyphosate on health -through the studies of bees exposed to the herbicide- could be due to its supposed harmful effect on beneficial intestinal microbiota. All of these considerations make the accurate monitoring of glyphosate and AMPA in the environment, drinking water and food commodities a public health and environmental priority.
The routine analysis of highly polar pesticide has always been challenging in liquid chromatography since these compounds are not compatible with the QuEChERS solid phase extraction associated with reversed phase liquid chromatography, commonly used in multiresidue analysis, nor normal phase liquid chromatography. Yet many popular pesticides fall into this category, including glyphosate and its metabolite, AMPA.
So far, the methods used for quantification of glyphosate and AMPA involved a derivatization step and day-long manipulations that may be regarded as tedious. In this work was a quick, cheap and effective direct determination method for glyphosate and AMPA in sugar beet root using an Hydrophilic Interaction Liquid Chromatography (HILIC) column with a diethylamine stationary phase fit for retention and separation of highly polar anionic compounds; based on the QuPPe-PO extraction method from the European Reference Laboratories for Single Residue Methods (EURL-SRM) and validated in accordance to the requirements in force at the BEAGx and the SANTE/12682/2019 guidelines.
The chosen matrix was sugar beet root. In the E.U., as resistant GM sugar beet are not approved for cultivation, glyphosate is only used for clearing weeds before sowing. However, in the U.S., almost all cultivated sugar beets are GM glyphosate-resistant crops, treated with the herbicide up to three times during cultivation. They are allowed for importation, food and feed use in the E.U., as well as their derived products and by-products. And as European public opinion on glyphosate is deteriorating, countries are progressively removing the active substance from the shelves for domestic users while countries are debating national bans, stakeholder of the sugar industry across Europe are increasingly willing to be able to monitor glyphosate residues in their raw material, products and by-products to prevent any public health crisis or scandal that could be detrimental to their sector. Le glyphosate (N-(phosphonométhyl)glycine) est l’herbicide le plus utilisé au monde. Il présente tous les avantages de l’herbicide parfait : il est universel dans sa manière de cibler une enzyme présente dans tous les végétaux, les algues et de nombreux microorganismes ; mais pas les animaux, rendant sa toxicité aiguë très faible pour la faune et l’humain, sa mobilité dans les sols a longtemps été considérée négligeable, il est dégradé par la lumière ultraviolette (incluant la lumière solaire) et des bactéries communes dans les sols, il permet de limiter le labour et ainsi de favoriser la conservation des sols en réduisant l’érosion; et, par-dessus tout, il a aussi l’énorme avantage d’épargner les cultures résistantes génétiquement modifiées, fournissant un énorme avantage financier et permettant de réduire l’utilisation d’autres herbicides plus toxiques ainsi que l’empreinte carbone par la réduction de l’utilisation de machines agricoles.
Cependant, le long débat sur sa cancérogénicité a été relancé en 2015 lorsque le Centre international de recherche sur le cancer a classé le glyphosate comme "potentiellement cancérigène pour l'homme" (catégorie 2A). Les effets chroniques du glyphosate et de son principal métabolite, l'acide aminométhylphosphonique (AMPA), (c'est-à-dire sa cancérogénicité, sa mutagénicité, son potentiel en tant que perturbateur endocrinien...) sont une réelle préoccupation sachant que le glyphosate est si largement utilisé qu'il a été démontré que les deux contaminants, et surtout l’AMPA qui est plus mobile, atteignent les nappes phréatiques et deviennent omniprésents dans les sols, les cours d'eau et les eaux usées. En effet, il a été démontré que la molécule est assez persistante dans l'eau et les sols dans un certain nombre de conditions de composition, de temps et de communautés bactériennes. La métabolisation du glyphosate dans les plantes est largement reconnue comme faible ou négligeable, ce qui suggère que les cultures génétiquement modifiées résistantes pourraient ainsi accumuler l'herbicide jusqu'à leur consommation. Enfin, quelques études et même des instances de l'Organisation mondiale de la santé ont commencé à suggérer que les effets négatifs du glyphosate sur la santé - notamment à travers les études sur les abeilles exposées à l'herbicide - pourraient être dus à son effet nocif supposé sur le microbiote intestinal bénéfique. Toutes ces considérations font de la surveillance précise du glyphosate et de l'AMPA dans l'environnement, l'eau potable et les produits alimentaires une priorité de santé publique et environnementale.
L’analyse de routine de pesticides hautement polaires a toujours été difficile en chromatographie liquide compte tenu que ces composés ne sont pas compatibles avec l’extraction en phase solide QuEChERS associée à la chromatographie liquide en phase inverse, couramment utilisée en analyse multi-résidus, ni avec la chromatographie liquide en phase normale. Pourtant, de nombreux pesticides populaires font partie de cette catégorie, y compris le glyphosate et son métabolite, l’AMPA.
Jusqu’à présent, les méthodes utilisées pour la quantification du glyphosate et de l’AMPA, impliquaient une étape de dérivatisation et des manipulations durant une journée entière pouvant être considérée comme fastidieuses. L’objectif de ce travail a été de développer une méthode rapide, peu coûteuse et efficace de détermination directe du glyphosate et de l’AMPA dans la betterave sucrière en utilisant une colonne de Chromatographie Liquide d’Interaction Hydrophile (HILIC) avec une phase stationnaire diéthylamine adaptée à la rétention et à la séparation de composés anioniques hautement polaires; sur la base de la méthode d’extraction QuPPe-PO des Laboratoires Européens de Référence pour les Méthodes monorésidus (EURL-SRM) et validée au regard des exigences en vigueur au BEAGx et dans les directives SANTE/12682/2019.
La matrice choisie a été la betterave sucrière. Dans l'Union européenne, la culture de betteraves sucrières résistantes génétiquement modifiées n’est pas autorisée, le glyphosate est uniquement utilisé pour éliminer les mauvaises herbes avant les semis. Toutefois, aux États-Unis, presque toutes les betteraves sucrières cultivées sont des cultures OGM résistantes au glyphosate, traitées avec cet herbicide jusqu'à trois fois durant leur culture. L’importation, l’utilisation pour l'alimentation humaine et animale de celles-ci est autorisée dans l’U.E., ainsi que leurs produits dérivés et sous-produits. À mesure que l'opinion publique européenne sur le glyphosate se détériore, que les pays retirent progressivement la substances actives des rayons pour l’usage domestique et tandis que les pays débattent des interdictions nationales, les parties prenantes de l'industrie sucrière en Europe sont de plus en plus désireuses de pouvoir surveiller les résidus de glyphosate dans leurs matières premières et leurs produits et sous-produits afin d'éviter toute crise de santé publique ou tout scandale pouvant nuire à leur secteur.

Glyphosate --- AMPA --- Sugar beet --- HILIC --- Underivatized --- Liquid Chromatography --- MS/MS --- Tandem Mass Spectrometry --- Direct --- Direct analysis --- Underivatised --- LC --- LC-MS/MS --- QuPPe-PO --- Glyphosate --- AMPA --- Betterave sucrière --- HILIC --- Directe --- Sans Dérivatisation --- Chromatographie Liquide --- LC --- LC-MS/MS --- Spectrométrie de masse en tandem --- Analyse Directe --- QuPPe-PO --- Physique, chimie, mathématiques & sciences de la terre > Chimie --- Sciences du vivant > Sciences des denrées alimentaires

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At present, cyanobacteria and their toxins (also known as cyanotoxins) constitute a major threat for freshwater resources worldwide. Cyanotoxin occurrence in water bodies around the globe is constantly increasing, whereas emerging, less studied or completely new variants and congeners of various chemical classes of cyanotoxins, as well as their degradation/transformation products are often detected. In addition to planctic cyanobacteria, benthic cyanobacteria, in many cases, appear to be important toxin producers, although far less studied and more difficult to manage and control. This Special Issue highlights novel research results on the structural diversity of cyanotoxins from planktic and benthic cyanobacteria, as well as on their expanding global geographical spread in freshwaters.

Research & information: general --- Environmental economics --- Meiktila Lake --- Raphidiopsis --- Microcystis --- cylindrospermopsin --- deoxycylindrospermopsin --- microcystin --- cyanobacteria --- cyanopeptides --- harmful bloom --- liquid chromatography-tandem mass spectrometry --- global natural product social networking (GNPS) --- dereplication strategy --- earthquakes --- harmful algal blooms --- sediment --- sediment cores --- co-occurrence --- toxicity --- plastics --- metals --- biocide --- anatoxin-a --- dihydroanatoxin-a --- Tychonema --- neurotoxicosis --- cyanotoxins --- macrophytes --- benthic --- tychoplanktic --- reservoir --- Maumee Bay --- Sandusky Bay --- Planktothrix --- anatoxin --- cyanotoxin detection --- harmful cyanobacterial blooms --- next-generation biomonitoring --- real-time PCR --- qPCR --- LC-MS/MS --- saxitoxin --- ESI-LC-MS/MS --- 16S rRNA phylogeny --- Azores --- eutrophication --- long term monitoring --- water quality --- microcystins --- anabaenopeptins --- microginins --- aeruginosins --- aeruginosamide --- SPE --- Lake Vegoritis --- deep-chlorophyll layers (DCLs) --- cyanobacterial toxins --- allelopathy --- bioactive metabolites --- hypoxia --- Georgian Bay --- peptide --- NRPS --- anabaenopeptin --- Synechococcus --- temperate lakes --- cyanotoxins (CTs) --- microcystins (MCs) --- volatile organic compounds (VOCs) --- taste and odor (T&O) compounds --- SPE-LC-MS/MS --- HS-SPME-GC/MS --- LC–qTRAP MS/MS --- fragmentation spectra --- structure elucidation --- cyanobacterial metabolites --- Greek freshwaters --- planktonic cyanobacteria --- blooms --- monitoring --- analysis --- mass spectrometry --- Liquid Chromatography with tandem mass spectrometry (LC-MS/MS) --- fish tissue --- shellfish --- detection methods --- n/a --- LC-qTRAP MS/MS

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Since its early introduction by the Russian botanist Mikhail Semyonovich Tsvet, chromatography has been undoubtedly the most powerful analytical tool in analytical chemistry. Separation, qualitative analysis, and quantitative analysis can be achieved by choosing the right conditions. Thus, numerous gas chromatographic, liquid chromatographic, and supercritical fluid chromatographic methods have been developed and applied for most types of samples and most kinds of analytes. Additionally, older varieties such as paper chromatography and thin-layer chromatography were pioneer analytical techniques in many laboratories. Especially when hyphenated to spectrometric techniques, chromatography also allows the identification of separated analytes in a single run. Highly sophisticated equipment can answer all analytical problems very quickly. Chromatographers cooperate with many scientific fields and give their lights to medical doctors, veterinarians, food scientists, biologists, dentists, archaeologists, etc. In this Special Issue, analytical chemists were invited to prove that chromatography-based separation techniques are the ultimate analytical tool and their significant contribution is reflected in ten interesting articles.

Research & information: general --- Chemistry --- Analytical chemistry --- polyamine --- steroid --- breast cancer --- liquid chromatography–tandem mass spectrometry --- serum --- photoaging --- proteomics --- genomics --- Swietenia macrophylla --- UV irradiation --- keratinocytes --- epidermal layer --- cosmetics --- natural product --- LC-MS/MS --- metabolomics --- targeted analysis --- nontargeted analysis --- sample preparation --- derivatization --- validation --- biomarkers --- mycophenolate mofetil --- mycophenolic acid --- pediatric patients --- limited sampling strategy --- multiple linear regression --- therapeutic drug monitoring --- almonds --- HPLC --- authenticity --- PCA --- tocopherols --- phenolics --- method validation --- Miang --- catechins --- caffeine --- gallic acid --- walnut septum --- UAE --- SPE --- flavonoids --- functional --- HPLC-DAD --- biotin acceptor peptide (BAP) --- biotin ligase BirA --- liquid chromatography tandem mass spectrometry (LC-MS/MS) --- multiple reaction monitoring (MRM) --- protein–protein interactions (PPIs) --- proximity utilizing biotinylation (PUB) --- greener HPTLC --- paracetamol --- simultaneous determination --- microflow LC-MS --- mLC-MS/MS --- liver fibrosis --- hemopexin --- biomarker --- polyamine --- steroid --- breast cancer --- liquid chromatography–tandem mass spectrometry --- serum --- photoaging --- proteomics --- genomics --- Swietenia macrophylla --- UV irradiation --- keratinocytes --- epidermal layer --- cosmetics --- natural product --- LC-MS/MS --- metabolomics --- targeted analysis --- nontargeted analysis --- sample preparation --- derivatization --- validation --- biomarkers --- mycophenolate mofetil --- mycophenolic acid --- pediatric patients --- limited sampling strategy --- multiple linear regression --- therapeutic drug monitoring --- almonds --- HPLC --- authenticity --- PCA --- tocopherols --- phenolics --- method validation --- Miang --- catechins --- caffeine --- gallic acid --- walnut septum --- UAE --- SPE --- flavonoids --- functional --- HPLC-DAD --- biotin acceptor peptide (BAP) --- biotin ligase BirA --- liquid chromatography tandem mass spectrometry (LC-MS/MS) --- multiple reaction monitoring (MRM) --- protein–protein interactions (PPIs) --- proximity utilizing biotinylation (PUB) --- greener HPTLC --- paracetamol --- simultaneous determination --- microflow LC-MS --- mLC-MS/MS --- liver fibrosis --- hemopexin --- biomarker

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Since its early introduction by the Russian botanist Mikhail Semyonovich Tsvet, chromatography has been undoubtedly the most powerful analytical tool in analytical chemistry. Separation, qualitative analysis, and quantitative analysis can be achieved by choosing the right conditions. Thus, numerous gas chromatographic, liquid chromatographic, and supercritical fluid chromatographic methods have been developed and applied for most types of samples and most kinds of analytes. Additionally, older varieties such as paper chromatography and thin-layer chromatography were pioneer analytical techniques in many laboratories. Especially when hyphenated to spectrometric techniques, chromatography also allows the identification of separated analytes in a single run. Highly sophisticated equipment can answer all analytical problems very quickly. Chromatographers cooperate with many scientific fields and give their lights to medical doctors, veterinarians, food scientists, biologists, dentists, archaeologists, etc. In this Special Issue, analytical chemists were invited to prove that chromatography-based separation techniques are the ultimate analytical tool and their significant contribution is reflected in ten interesting articles.

Research & information: general --- Chemistry --- Analytical chemistry --- polyamine --- steroid --- breast cancer --- liquid chromatography–tandem mass spectrometry --- serum --- photoaging --- proteomics --- genomics --- Swietenia macrophylla --- UV irradiation --- keratinocytes --- epidermal layer --- cosmetics --- natural product --- LC-MS/MS --- metabolomics --- targeted analysis --- nontargeted analysis --- sample preparation --- derivatization --- validation --- biomarkers --- mycophenolate mofetil --- mycophenolic acid --- pediatric patients --- limited sampling strategy --- multiple linear regression --- therapeutic drug monitoring --- almonds --- HPLC --- authenticity --- PCA --- tocopherols --- phenolics --- method validation --- Miang --- catechins --- caffeine --- gallic acid --- walnut septum --- UAE --- SPE --- flavonoids --- functional --- HPLC-DAD --- biotin acceptor peptide (BAP) --- biotin ligase BirA --- liquid chromatography tandem mass spectrometry (LC-MS/MS) --- multiple reaction monitoring (MRM) --- protein–protein interactions (PPIs) --- proximity utilizing biotinylation (PUB) --- greener HPTLC --- paracetamol --- simultaneous determination --- microflow LC-MS --- mLC-MS/MS --- liver fibrosis --- hemopexin --- biomarker