Miniaturisierte online-betriebene umfassend zweidimensionale Flüssigkeitschromatografie

This thesis deals with the development of a novel multidimensional separation system for the qualitative screening analysis of complex samples that potentially contain hundreds of semi- or nonvolatile analytes. This system is based on a combination of online, comprehensive two-dimensional liquid chromatography and hybrid high-resolution mass spectrometry. A consistent miniaturization of the chromatographic part to nano- and capillary-LC in the first and second dimension, respectively, allowed the mass spectrometer to be hyphenated at full flow rate compatibility, without a flow split after the fast second LC dimension. To facilitate the choice of the conditions for an example application, two studies were included that focused on the applicability of high-temperature LC in the second dimension. First, the influence of high column temperatures on solvent effects observable for ambient temperature reversed-phase second dimensions was investigated by a peak shape study at isocratic elution conditions. Although high temperatures increase solvent compatibility by the reduction of viscosity differences, peak broadening by solvent strength effects cannot be overcome by an increase in temperature. The pre-dominance of these effects at any temperature underline the importance of a sufficiently low transfer volume to the second dimension. Second, eight modern stationary phases were investigated for their long-term high-temperature and pH stability. In this context, a retention factor analysis approach was developed that helps monitoring the status of silica-based reversed-phase columns using not only hydrophobicity losses but also the increase in silanophilic interactions. Accordingly, particles on the basis of the ethylene bridged hybrid (BEH) technology represent the most stable silica-based particles. Nonetheless, for the final implementation of the multidimensional system, sub-3-µm core-shell C18 particle technology was combined with elevated temperature and high pressures to obtain a gradient cycle time of one minute in the second dimension. In the first dimension, a porous graphitic carbon stationary phase was used that allowed implementing a large volume injection. The potential of the multidimensional system was successfully demonstrated by performing a suspected screening with ninety-nine compounds on a wastewater sample. Sixty-five of the suspected analytes were found. An orthogonality of the LC dimensions of 0.6 was calculated via a surface coverage approach referring to the screened compounds. The low solvent consumption makes the novel multidimensional system an environmentally and economically interesting alternative to systems that apply conventionally sized second dimension columns.Diese Dissertation handelt von der Entwicklung eines neuartigen, multidimensionalen Trennsystems zur qualitativen Screeninganalyse komplexer Proben, welche hunderte mittel- bis schwerflüchtige Analyten beinhalten können. Dieses System kombiniert die online-betriebene, umfassend zweidimensionale Flüssigkeitschromatografie mit der hochauflösenden Hybrid-Massenspektrometrie. Eine konsequente Miniaturisierung der Chromatografie zu Nano- und Kapillar-LC in der ersten und zweiten Dimension ermöglichte eine Kopplung des Massenspektrometers unter vollständig kompatiblen Flussratenbedingungen (d. h. ohne einen Split nach der schnellen zweiten Dimension). Um die Wahl der Bedingungen für eine Beispielapplikation zu erleichtern, wurden zwei Studien mit Fokus auf der Verwendbarkeit hoher Ofentemperaturen für die zweite Dimension eingebunden. Zum einen wurde mittels einer Peakformstudie bei isokratischer Elution der Einfluss hoher Ofentemperaturen auf Lösemitteleffekte untersucht, welche auftreten können, wenn Umkehrphasen in der zweiten Dimension verwendet werden. Obwohl hohe Temperaturen die Lösemittelkompatibilität erhöhen, da Viskositätsunterschiede verringert werden, so kann eine durch Lösemittel-stärkeeffekte hervorgerufene Bandenverbreiterung nicht durch eine Temperaturerhöhung kompensiert werden. Die Prädominanz dieser Effekte bei jeglicher Temperatur unterstreicht die Notwendigkeit eines hinreichend kleinen Transfervolumens zur zweiten Dimension. Zum anderen wurden acht moderne stationäre Phasen in Bezug auf ihre Temperatur- und pH-Stabilität untersucht. Eine Vergleichsmethodik mittels Retentionsfaktorenanalyse wurde entwickelt, um den Zustand von silika-basierten Umkehrphasen anhand von Hydrophobi-zitätsverlusten und der Zunahme von silanophilen Wechselwirkungen überwachen zu können. Demnach basieren die stabilsten silika-basierten Partikel auf der BEH-Hybrid-Technologie. Nichtsdestotrotz wurden für das multidimensionalen System teilporöse Partikel (< 3 µm) mit C18-Funktionalisierung in Kombination mit erhöhter Temperatur und hohem Druck in der zweiten Dimension verwendet, um eine Gradienten-Zykluszeit von einer Minute zu realisieren. In der ersten Dimension wurde eine stationäre Phase aus porösem, graphitisiertem Kohlenstoff eingesetzt, welche eine großvolumige Injektion erlaubte. Das Potential des multidimensionalen Systems wurde demonstriert, indem ein 99-Analyten-Suspected-Screening auf eine stark matrixbehaftete Abwasserprobe angewendet wurde. 65 der Zielanalyten wurden gefunden. Bezogen auf die 99 Zielanalyten wurde über einen Surface-Coverage-Ansatz eine Orthogonalität von 0,6 bestimmt. Der geringe Lösemittelverbrauch macht das multidimensionale System zu einer umweltfreundlichen und wirtschaftlichen Alternative zu Techniken, die konventionelle HPLC in der zweiten Dimension nutzen

Implementation of green extraction and isolation methodologies for the recovery of bioactive compounds from olive-growing products and by-products

Η διδακτορική διατριβή πραγματεύεται την βέλτιστη αξιοποίηση των παραπροιόντων της ελαιοκομίας για την παραλαβή βιολογικά δραστικών ενώσεων με την βελτιστοποιημένη εφαρμογή πράσινων μεθοδολογιών εκχύλισης και απομόνωσης. Πιο συγκεκριμένα, τέσσερα κύρια παραπροιόντα αξιοποιούνται: 1. Φύλλα ελιάς 2. Ύδωρ ξεπικρίσματος ελιάς 3. Αποστάγματα εξευγενισμού ελαιολάδου 4. Διφασικος πυρηήνας Οι κυριότερες μεθοδολογίες βασίζονται στις κατωθι τεχνολογίες: 1. Eκχύλιση με υπερκρίσιμα ρευστά 2. Κατ&apos;αντιρροή χρωματογραφία 3.Υγρή/υγρή εκχύλιση 4. Μακρόπορες ρητίνες προσροφησης Οι k;yriew βιοδραστικές ενώσεις που στοχεύονται είναι οι εξής: 1.Eλευρωπαίνη 2.Υδρόξυτυροσόλη 3.ΣκουαλένιοThe experimental work of this PhD thesis has been scheduled on a three-axis base. The aims that were set, they concerned the optimal exploitation of four different by-products of the table olive, olive oil and olive kernel oil industries, for the recovery of specific high added-value compounds with well-known biological properties. Those natural products were desired either in the form of enriched fractions or pure compounds. The prerequisite was to utilize as eco-friendly technologies as possible for extraction and purification and to optimize the processes in laboratory as well as in pilot scale. Thus, trustworthy estimation of industrial feasibility is provided. The main technologies that were implicated for the recovery of the target compounds are: &#127; Supercritical fluid extraction &#127; Pressurized liquid (and subcritical water) extraction &#127; Liquid/liquid extraction &#127; Adsorption resin technology &#127; Centrifugal Partition Chromatography The by-products that were the subject of the tracing/ extraction/ enrichment/ identification/ quantification on studies for this PhD thesis were the following: &#127; Olive leaves (by-products of the pruning of the trees and of the olive fruit harvest) &#127; Olive mill pomace waste (biphasic process) &#127; Table olive process wastewater (by-product of the debittering process for the production of table olives) &#127; Olive kernel oil deodorization distillates (by-product of the refining process for the production of olive kernel oil from olive pomace) The natural compounds that were targeted for their recovery, enrichment and isolation due to their well-established (and still under research) biological properties and their application in pharmaceutical, phytotherapeutical, nutraceutical, cosmetic and cosmeceutical industries were respectively: &#127; Oleuropein &#127; Hydroxytyrosol &#127; Squalene In all cases, not only biomarkers’ content but also the overall chemical profile of the extracts was studied. The applied scientific interest of this work was that novel green extraction technologies and combinatorial processes as well as experimental design were implemented in lab and pilot scale for the exploitation of certain by-products that occur in very large quantities every year as a result of the agricultural/ industrial processing of the olive tree, with the aim of recovering high added value natural products

New Insights on Biofilm Antimicrobial Strategies

Over the last few decades, the study of microbial biofilms has been gaining interest among the scientific community. These microbial communities comprise cells adhered to surfaces that are surrounded by a self-produced exopolymeric matrix that protects biofilm cells against different external stresses. Biofilms can have a negative impact on different sectors within society, namely in agriculture, food industries, and veterinary and human health. As a consequence of their metabolic state and matrix protection, biofilm cells are very difficult to tackle with antibiotics or chemical disinfectants. Due to this problem, recent advances in the development of antibiotic alternatives or complementary strategies to prevent or control biofilms have been reported. This book includes different strategies to prevent biofilm formation or to control biofilm development and includes full research articles, reviews, a communication, and a perspective

Hybrid Free-Space Optical and Visible Light Communication Link

V součastnosti bezdrátové optické komunikace (optical wireless communication, OWC) získávají širokou pozornost jako vhodný doplněk ke komunikačním přenosům v rádiovém pásmu. OWC nabízejí několik výhod včetně větší šířky přenosového pásma, neregulovaného frekvenčního pásma či odolnosti vůči elektromagnetickému rušení. Tato práce se zabývá návrhem OWC systémů pro připojení koncových uživatelů. Samotná realizace spojení může být provedena za pomoci různých variant bezdrátových technologií, například pomocí OWC, kombinací různých OWC technologií nebo hybridním rádio-optickým spojem. Za účelem propojení tzv. poslední míle je analyzován optický bezvláknový spoj (free space optics, FSO). Tato práce se dále zabývá analýzou přenosových vlastností celo-optického více skokového spoje s důrazem na vliv atmosférických podmínek. V dnešní době mnoho uživatelů tráví čas ve vnitřních prostorech kanceláří či doma, kde komunikace ve viditelném spektru (visible light communication, VLC) poskytuje lepší přenosové parametry pokrytí než úzce směrové FSO. V rámci této práce byla odvozena a experimentálně ověřena závislost pro bitovou chybovost přesměrovaného (relaying) spoje ve VLC. Pro propojení poskytovatele datavých služeb s koncovým uživatelem může být výhodné zkombinovat více přenosových technologií. Proto je navržen a analyzovám systém pro překonání tzv. problému poslední míle a posledního metru kombinující hybridní FSO a VLC technologie.The field of optical wireless communications (OWC) has recently attracted significant attention as a complementary technology to radio frequency (RF). OWC systems offer several advantages including higher bandwidth, an unregulated spectrum, resistance to electromagnetic interference and a high order of reusability. The thesis focuses on the deployment and analyses of end-user interconnections using the OWC systems. Interconnection can be established by many wireless technologies, for instance, by a single OWC technology, a combination of OWC technologies, or by hybrid OWC/RF links. In order to establish last mile outdoor interconnection, a free-space optical (FSO) has to be investigated. In this thesis, the performance of all-optical multi-hop scenarios is analyzed under atmospheric conditions. However, nowadays, many end users spend much time in indoor environments where visible light communication (VLC) technology can provide better transmission parameters and, significantly, better coverage. An analytical description of bit error rate for relaying VLC schemes is derived and experimentally verified. Nonetheless, for the last mile, interconnection of a provider and end users (joint outdoor and indoor connection) can be advantageous when combining multiple technologies. Therefore, a hybrid FSO/VLC system is proposed and analyzed for the interconnection of the last mile and last meter bottleneck

Metallopeptides and metalloproteins in chemical biology: from DNA binding to intracellular catalysis

En esta tesis doctoral se describe el diseño, síntesis y aplicación de metalopéptidos y metaloproteínas en diferentes campos, englobados todos ellos dentro del área de la química biológica. En el primer capítulo se describe una nueva generación de péptidos y miniproteínas de unión al ADN, capaces de reconocer sitios diseñados del ADN con alta afinidad y selectividad. El segundo capítulo se centra en un metalopéptido capaz de reconocer una proteína oncogénica y modificar su actividad. En el tercer apartado de la tesis se aborda el uso de un metalopéptido capaz de internalizar en células de mamífero y llevar a cabo reacciones químicas diseñas. Por último, en el capítulo 4, se describe el diseño de unas nuevas metaloproteínas capaces de ensamblarse en el interior celular, estudiando su reactividad para funcionar como metaloenzimas

Novel Analytical Methods in Food Analysis

This reprint provides information on the novel analytical methods used to address challenges occurring at academic, regulatory, and commercial level. All topics covered include information on the basic principles, procedures, advantages, limitations, and applications. Integration of biological reagents, (nano)materials, technologies, and physical principles (spectroscopy and spectrometry) are discussed. This reprint is ideal for professionals of the food industry, regulatory bodies, as well as researchers