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Gas chromatography is one of the most used analytical techniques in the industry. It is a powerful tool with a wide range of applications. This book presents recent advances in gas chromatography, multidimensional gas chromatography, and gas chromatography mass spectrometry. It also discusses inverse gas chromatography. The main focus is the use of gas chromatography techniques to analyze petroleum fluids, biomass, and ionic liquids in medical and petrochemical industries.

Gas chromatography.

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Gas chromatography is one of the most used analytical techniques in the industry. It is a powerful tool with a wide range of applications. This book presents recent advances in gas chromatography, multidimensional gas chromatography, and gas chromatography mass spectrometry. It also discusses inverse gas chromatography. The main focus is the use of gas chromatography techniques to analyze petroleum fluids, biomass, and ionic liquids in medical and petrochemical industries.

Gas chromatography.

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The normal functioning of the endocrine system of humans and animals can be harmed by chemical compounds when they are present above a certain threshold in the environment. These compounds are referred to as endocrine disrupting compounds (EDCs). (Tyler et al., 2005, de Jesus Gaffney et al., 2014, Bieman, Blüher and Isermann, 2021). 
According to Sonnenschein and Soto (1998), four abilities can make EDCs hazardous: "(1) mimic the effect of endogenous hormones, (2) antagonize the effect of endogenous hormones, (3) disrupt the synthesis and metabolism of endogenous hormones, and (4) disrupt the synthesis and metabolism of hormone receptors.".
Among all EDCs, some of the most potent are estrogenic compounds (e-EDCs), so-called because they are able to mimic the natural and endogenous hormone called estradiol (E2) (Arcand-Hoy, Nimrod and Benson, 1997). There are three main types of e-EDCs, the synthetic (eg. pharmaceuticals, pesticides, surfactants, etc...) and the naturally produced which are either endogenous hormones from humans and animals (e.g. E2) or from plants (phytoestrogens) (Hamid and Eskicioglu, 2012 citing Caliman and Gavrilescu, 2009 and Burkhardt-Holm, 2010). e-EDCs are now ubiquitous in the environment and some of these compounds can be persistent. The major concern is probably the fate of e-EDCs in water as the aquatic environment represents the "ultimate sink for most chemicals" (Sumpter, 1998). e-EDCs can end up in the aquatic environment through three different pathways: the domestic effluents of wastewater treatment plants (WWTPs), the industrial effluents, and the agricultural waste products (Arcand-Hoy, Nimrod and Benson, 1997, Campbell et al., 2006).
Along with E2, highly important are also estrone (E1) and ethinyl estradiol (EE2). Their use includes oral contraceptive pills, hormone replacement therapy (HRT) and growth promoters in livestock production. The natural (endogenous hormones E1 and E2) and synthetic estrogens (e.g EE2) are excreted through urine and feces. These compounds have been demonstrated to contribute to the estrogenic activity of sewage or wastewater treatment plant (WWTP) effluents that are eventually discharged in the aquatic environment (Huang and Sedlak, 2001, Sumpter and Jobling, 2013, Valdés et al., 2015). The occurrence of such contaminants in water could further cause environmental hazards such as male fish feminization even when present at the nanogram per liter level (Purdom et al., 1994, Parrott and Blunt, 2004). Moreover, as these contaminants are persistent, it is suspected that they can bioaccumulate in aquatic organisms and ultimately be consumed by humans through the food chain route (Bilal, Barceló and Iqbal, 2021).
Accordingly, the E1, E2 and EE2 were included in the EU Water Framework Directive Watch List (WL) published in 2015. The EU WL established a list of substances that may pose a risk for the aquatic environment, but for which monitoring data are lacking to assess the actual risk. The proposed maximum detection limits (LODs) in this WL are of 0.4 ng/L for E1 and E2 and of 0.035 ng/L for EE2 (EC Decision 2015/495).
Seeing the extremely low sensitivity (i.e. ultra-trace level) required to meet the WL requirements, there is the need for performant, robust, selective and sensitive analytical methods. In this study, the feasibility of new methods using sorptive extraction, miniaturized techniques, derivatization and gas chromatography (GC) coupled with mass spectrometry (MS) or tandem mass spectrometry (MS/MS) was investigated. Le fonctionnement normal du système endocrinien des humains et des animaux peut être 
perturbé par des composés chimiques lorsqu'ils sont présents dans l'environnement au-delà d'un 
certain seuil. Ces composés sont appelés perturbateurs endocriniens (PEs). (Tyler et al., 2005, 
de Jesus Gaffney et al., 2014, Bieman, Blüher et Isermann, 2021). 
Selon Sonnenschein et Soto (1998), quatre capacités peuvent rendre ces PEs dangereux : " (1) 
imiter l'effet des hormones endogènes, (2) antagoniser l'effet des hormones endogènes, (3) 
perturber la synthèse et le métabolisme des hormones endogènes, et (4) perturber la synthèse 
et le métabolisme des récepteurs hormonaux ".
Parmi tous les PEs, certains des plus puissants sont les composés œstrogéniques (PE-e), appelés 
ainsi car ils sont capables d'imiter l'hormone naturelle et endogène appelée œstradiol (E2) 
(Arcand-Hoy, Nimrod et Benson, 1997). Il existe trois principaux types de PE-e, les 
synthétiques (par exemple, les produits pharmaceutiques, les pesticides, les agents de surface, 
etc.) et les produits naturels qui sont soit des hormones endogènes provenant des humains et 
des animaux (par exemple, E2) ou soit provenant des plantes (phytoestrogènes) (Hamid et 
Eskicioglu, 2012 citant Caliman et Gavrilescu, 2009 et Burkhardt-Holm, 2010). Les PE-e sont 
maintenant omniprésents dans l'environnement et certains de ces composés peuvent être 
persistants. La principale préoccupation est probablement le devenir des PE-e dans l'eau, car 
l'environnement aquatique représente le " puit ultime pour la plupart des produits chimiques " 
(Sumpter, 1998). Les PE-e peuvent se retrouver dans l'environnement aquatique par trois voies 
différentes : les effluents domestiques des stations d'épuration (STEP), les effluents industriels 
et les déchets agricoles (Arcand-Hoy, Nimrod et Benson, 1997, Campbell et al., 2006).
Outre E2, l'estrone (E1) et l'éthinylestradiol (EE2) sont également très importants. Leur 
utilisation comprend les pilules contraceptives orales, la thérapie de remplacement hormonal
(TRH) et les stimulateurs de croissance dans la production animale. Les œstrogènes naturels 
(hormones endogènes E1 et E2) et synthétiques (par exemple EE2) sont excrétés dans l'urine 
et les fèces. Il a été démontré que ces composés contribuent à l'activité œstrogénique des eaux 
usées ou des effluents des stations d'épuration des eaux usées (STEP) qui sont finalement 
déversés dans l'environnement aquatique (Huang et Sedlak, 2001, Sumpter et Jobling, 2013, 
Valdés et al., 2015). La présence de ces contaminants dans l'eau pourrait en outre provoquer 
des risques environnementaux tels que la féminisation des poissons mâles, même lorsqu'ils sont 
présents au niveau du nanogramme par litre (Purdom et al., 1994, Parrott et Blunt, 2004). De 
plus, comme ces contaminants sont persistants, on soupçonne qu'ils peuvent se bioaccumuler 
dans les organismes aquatiques et finalement être consommés par les humains à travers la 
chaîne alimentaire (Bilal, Barceló et Iqbal, 2021).
En conséquence, les E1, E2 et EE2 ont été inclus dans la liste de surveillance de la directive cadre sur l'eau de l'UE (WL) publiée en 2015. La WL de l'UE a établi une liste de substances 
qui peuvent présenter un risque pour l'environnement aquatique, mais pour lesquelles les 
données de surveillance font défaut pour évaluer le risque réel. Les limites maximales de 
détection (LOD) proposées dans cette WL sont de 0,4 ng/L pour E1 et E2 et de 0,035 ng/L pour 
EE2 (Décision CE 2015/495).
Au vu de la sensibilité extrêmement faible (c'est-à-dire au niveau de l'ultra-trace) requise pour 
répondre aux exigences de la WL, il est nécessaire de disposer de méthodes analytiques 
performantes, robustes, sélectives et sensibles. Dans cette étude, la faisabilité de nouvelles 
méthodes utilisant l'extraction sorptive, les techniques miniaturisées, la dérivatization et la 
chromatographie en phase gazeuse (GC) couplée à la spectrométrie de masse (MS) ou à la 
spectrométrie de masse en tandem (MS/MS) a été étudiée.

Estrogens, water, contaminants analyzis, mass spectrometry, gas chromatography --- Physique, chimie, mathématiques & sciences de la terre > Chimie

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Practical Application of Supercritical Fluid Chromatography for Pharmaceutical Research and Development provides a valuable "go-to" reference for many difficult-to-solve challenges using pertinent chromatographic theory, first-hand case studies, and examples provided from academic and industry experts. This text also enables professors teaching an analytical instrumental course to introduce and instruct students about one of the most sustainable and powerful separation methods currently available. While the text has broad applicability across industrial sectors, it focuses primarily on application in the pharmaceutical industry. The book is designed to allow readers to align current HPLC/UHPLC capabilities with SFC as an orthogonal tool for project specific methods in the pharmaceutical industry. It highlights where SFC falls on the spectrum of useful chromatographic tools for routine and challenging separative methods. Experienced HPLC users who are interested in developing knowledge in orthogonal separation techniques, as well as newcomers to the field of separation science, will find this text particularly useful. Chapters address where SFC may fit the analytical needs of the pharmaceutical industry and alert the readers as to where the technique will not fit. Readers will gain an understanding of how and where SFC may be applied and adapted more routinely across the pharmaceutical industry as a 'green' way of undertaking separation opportunities and challenges. Areas within the pharmaceutical industry include early drug discovery, process chemistry, and late stage development and manufacturing.

Drugs --- Pharmacy --- Supercritical fluid chromatography. --- Research --- Methodology. --- SFC (Chromatography) --- Supercritical gas chromatography --- Gas chromatography --- Chemistry --- Medicine --- Materia medica --- Pharmacology --- Medicaments --- Medications --- Medicine (Drugs) --- Medicines (Drugs) --- Pharmaceuticals --- Prescription drugs --- Bioactive compounds --- Medical supplies --- Pharmacopoeias --- Chemotherapy --- Chromatography, Supercritical Fluid --- Drug Development --- Pharmaceutical Research --- methods

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The main focus of this thematic collection is on the antimicrobial activity of essential oils and their combinations with conventional antimicrobial drugs, including the eradication of the existing biofilms, the explanation of the mechanisms underlying antimicrobial activity, and the preparation of stable formulations with essential oils, which boost their antimicrobial activity and provide greater stability. These issues are addressed in four research papers and three reviews, which present novel advances in the development and application of essential oils as antimicrobial agents via combinatorial and nano-based approaches.

Humanities --- Social interaction --- biofilm --- common juniper --- immortelle --- nontuberculous mycobacteria --- stainless steel --- Pistacia lentiscus var. Chia --- Chios mastic --- ageing --- chemical profile --- antibacterial --- antifungal --- α-pinene --- β-myrcene --- GC-MS --- HPTLC --- chitosan --- coating --- essential oils --- liposomes --- mechanism --- polyelectrolyte --- bacterial biofilm --- antimicrobial --- medical devices --- antimicrobial resistance --- combination therapy --- lavender essential oil --- nanoencapsulation --- synergy --- Apiaceae --- gas chromatography-mass spectrometry --- volatiles --- antimicrobial activity --- coumarins --- nanoemulsion --- Croton cajucara --- essential oil --- antifungal activity --- biofilm --- common juniper --- immortelle --- nontuberculous mycobacteria --- stainless steel --- Pistacia lentiscus var. Chia --- Chios mastic --- ageing --- chemical profile --- antibacterial --- antifungal --- α-pinene --- β-myrcene --- GC-MS --- HPTLC --- chitosan --- coating --- essential oils --- liposomes --- mechanism --- polyelectrolyte --- bacterial biofilm --- antimicrobial --- medical devices --- antimicrobial resistance --- combination therapy --- lavender essential oil --- nanoencapsulation --- synergy --- Apiaceae --- gas chromatography-mass spectrometry --- volatiles --- antimicrobial activity --- coumarins --- nanoemulsion --- Croton cajucara --- essential oil --- antifungal activity