[Memel als Brücke zu den baltischen Ländern] / Ralph Tuchtenhagen

Index Scriptorium Estoniae

Tuchtenhagen, Ralph, 1961-

2014-01-01

Arvustus: Memel als Brücke zu den baltischen Ländern. Kulturgeschichte Klaipedas vom Mittelalter bis ins 20. Jahrhundert. (Tagungsberichte der Historischen Kommission für ost- und westpreussische Landesforschung. Bd. 26)

Abfallentsorgung zu Lasten der Bürger? : Probleme der Kreislaufwirtschaft und Lösungsansätze für eine Entlastung der Haushalte

OpenAIRE

Kaimer, Martin; Schade, Diethard

2000-01-01

Das heutige Abfallentsorgungssystem und die ihm zugrunde liegenden gesetzlichen Regelungen haben eine lange Vorgeschichte und beruhen auf unterschiedlichen Zielsetzungen. Im Ergebnis haben die daraus folgenden Anforderungen zu teilweise fragwürdigen Entsorgungspfaden, zu einem komplizierten Nebeneinander privater und öffentlichrechtlicher Entsorger und vor allem zu höheren Müllgebühren für die Bürger geführt. Ausgehend von den Wirkungen, die mit der Umsetzung der gesetzlichen Regelungen errei...

Zu einer inhaltsorientierten Theorie des Lernens und Lehrens der biologischen Evolution

Science.gov (United States)

Wallin, Anita

Der Zweck dieser Studie (zwecks Überblick siehe dazu Abb. 9.1) war zu untersuchen, wie die Schüler der Sekundarstufe II ein Verständnis von der Theorie der biologischen Evolution entwickeln. Vom Ausgangspunkt "Vorurteile der Schüler“ ausgehend wurden Unterrichtssequenzen entwickelt und drei verschiedene Lernexperimente in einem zyklischen Prozess durchgeführt. Das Wissen der Schüler wurde vor, während und nach den Unterrichtssequenzen mit Hilfe von schriftlichen Tests, Interviews und Diskussionsrunden in kleinen Gruppen abgefragt. Etwa 80 % der Schüler hatten vor dem Unterricht alternative Vorstellungen von Evolution, und in dem Nachfolgetest erreichten circa 75 % ein wissenschaftliches Niveau. Die Argumentation der Schüler in den verschiedenen Tests wurde sorgfältig unter Rücksichtnahme auf Vorurteile, der konzeptionellen Struktur der Theorie der Evolution und den Zielen des Unterrichts analysiert. Daraus konnten Einsichten in solche Anforderungen an Lehren und Lernen gewonnen werden, die Herausforderungen an Schüler und Lehrer darstellen, wenn sie anfangen, evolutionäre Biologie zu lernen oder zu lehren. Ein wichtiges Ergebnis war, dass das Verständnis existierender Variation in einer Population der Schlüssel zum Verständnis von natürlicher Selektion ist. Die Ergebnisse sind in einer inhaltsorientierten Theorie zusammengefasst, welche aus drei verschiedenen Aspekten besteht: 1) den inhaltsspezifischen Aspekten, die einzigartig für jedes wissenschaftliche Feld sind; 2) den Aspekten, die die Natur der Wissenschaft betreffen; und 3) den allgemeinen Aspekten. Diese Theorie kann in neuen Experimenten getestet und weiter entwickelt werden.

Rückwärtsintegration - Zu den Verhältnissen Gymnasium, Hochschule und Arbeitswelt

Science.gov (United States)

Schmid, Gerhard; Heppner, Winfried; Focht, Eva

In seiner 2007 erschienen Sammlung von Vorträgen und Essays beschäftigt sich Wolfgang Frühwald, mit der Frage "Wieviel Wissen brauchen wir?“ [1] Die Kernproblematik moderner Wissenschaft und Forschung sieht der Autor, emeritierter Ordinarius für Neuere Deutsche Literaturwissenschaft und von 1992 bis 1997 Präsident der Deutschen Forschungsgemeinschaft, einerseits in der zunehmenden Spezialisierung der Wissenschaftsbereiche, andererseits in der Gefahr der Abkoppelung der Naturwissenschaften von den Geisteswissenschaften. Wiederholt plädiert er dafür, über der rasanten Entwicklung beispielsweise in der Biologie und Physik, die historische, gesellschaftliche und besonders die ethische Dimension der Forschung nicht zu übersehen und fordert eine übergeordnete Theorie der Wissenschaft, die nur im Dialog zwischen den einzelnen Fachgebieten zu entwickeln sei.

Ein Paradigma, das es weiter zu konkretisieren gilt. Der Begriff der Mediatisierung bei Krotz

Directory of Open Access Journals (Sweden)

Hans-Dieter Kübler

2010-01-01

Full Text Available Rezension zu: Krotz, Friedrich. 2007. Mediatisierung: Fallstudien zum Wandel von Kommunikation. 1. Aufl. Medien - Kultur - Kommunikation. Wiesbaden: VS Verlag für Sozialwissenschaften.

Gesundheits- und Konzentrationsfähigkeitsuntersuchungen bei Büroangestellten im Rahmen einer Pilotstudie zu Exposition gegenüber tonerbasierten Bürogeräten

OpenAIRE

Schumann, Henrik

2011-01-01

Ziel der vorliegenden Arbeit war es zu untersuchen, ob und gegebenenfalls in welchem Maße der Betrieb von Laserdruckern und Fotokopiergeräten in Büro-räumen Einfluss auf die von Büroangestellten geäußerten Konzentrations- und Gesundheitsbeschwerden hat. Die Studie wurde dabei als eine Pilotstudie an-gelegt, die primär zur Aufgabe hatte, Erhebungsinstrumente auszuwählen, wei-terzuempfehlen und auf ihre Einsetzbarkeit zu überprüfen. Zu diesem Zwecke wurden zwischen Januar und Oktober 2006 in Ko...

Literatur zu Gast im Globe

CERN Multimedia

2006-01-01

Der deutsche Schriftsteller Thomas LEHR liest am 23. März 2006 aus seinem Roman '42', einem philosophischen Abenteuerroman über die Suche nach der Zeit, erzählt in einer funkelnden und souveränen Sprache. Eine Welt von vernichtender Schönheit und bizarren Schrecken wartet auf eine Besuchergruppe, die in der Nähe von Genf die unterirdischen Anlagen des Forschungszentrums für Teilchenphysik CERN besichtigt. Als sie um 12:47:42 wieder ans Tageslicht tritt, scheint ganz Europa in einen Dornröschenschlaf gefallen. Allein die 70 Besucher können sich noch bewegen. Monate und Jahre verharrt die Welt wie in einer riesigen dreidimensionalen Fotografie, bis ein wiederum schockierendes Ereignis die 'Chronifizierten' aus ihren physikalischen Spekulationen und seltsamen Lebensformen reisst. Zu dieser literarischen Veranstaltung im 'Globe of Science and Innovation' laden gemeinsam das Generalkonsulat der Bundesrepublik Deutschland in Genf und CERN ein. Vor Beginn der Lesung wird eine Führung in deutscher Sprac...

Rezension zu: Elisabeth Tuider, Martin Dannecker: Das Recht auf Vielfalt. Aufgaben und Herausforderungen sexueller Bildung. Göttingen: Wallstein Verlag 2016.

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Marcus Felix

2017-06-01

Full Text Available Sexuelle Bildung ist und war schon immer eine umkämpfte Disziplin der Pädagogik. Dabei ist die aktuelle Erregung um diese als Reaktion auf die fortschreitende Pluralisierung von Lebensentwürfen und die Liberalisierung von Normen und Werten zu verstehen, auf die eine diversitätsbewusste Sexualpädagogik in ihren Konzepten Bezug nimmt, die aber von ultrakonservativen, fundamentalistischen und rechtsradikalen Gruppierungen angegriffen werden. Diese Gemengelage nehmen die Autor_innen zum Anlass, um ausgewählte in der Kritik stehende Inhalte einer sexualfreundlichen Bildung zu besprechen und die Argumentationsmuster der Kritiker_innen zu verdeutlichen. Damit trägt der Band zur (Re-Kontextualisierung und Versachlichung einer hochemotionalen Auseinandersetzung über sexuelle Bildung bei.

Identification of hardly biodegradable residuals (sulfur- and nitrogen-containing substances) during waste water treatment, including the development of analytical methods; Identifizierung von schwer abbaubaren Reststoffen (stickstoff- und schwefelhaltigen Verbindungen) bei der Abwasserbehandlung, einschliesslich analytischer Methodenentwicklung

Energy Technology Data Exchange (ETDEWEB)

Moehle, E; Huber, A; Metzger, J W

1999-07-01

Organic residuals in sewage, which are not removed completely by waste water treatment may be relevant in environmental toxicology and may disturb drinking water treatment processes. The organic residuals must be identified before new techniques to eliminate these substances from waste water can be developed and steps can be taken to prevent them from polluting waste waters. In the research project sum parameters of sulfur- and nitrogen-containing substances in municipal waste water were determined. A new method was developed to determine the organic sulfur in compounds absorbed on activated carbon (AOS). The determination of dissolved organic nitrogen (DON) was calculated as the difference between total nitrogen and the sum of NH{sub 4}{sup +}-N, NO{sub 3}{sup -}-N and NO{sub 2}{sup -}N. The removal of organic substances from the inorganic matrix was only possible for standard solutions, but not for real samples. More than 60 substances contributing to the sum parameters could be identified with GC-MS and GC-AED, an most of them could be quantified. 30-70% of the sulfur-containing substances detected with GC-AED could be identified. With the GC-MS screening method 21 drugs or drug metabolites could be identified and partly quantified. Hydrophilic organic residuals were identified and quantified with high performance liquid chromatography coupled with UV- and fluorescence detectors and also with a mass detector (ESI-MS-MS). With the methods described only a small percentage of the sum of AOS and DON could be detected, although new materials for the solid phase enrichment and new analytical methods, such as HPLC-MS-MS were used. In order to get information about the degree of elimination (absorption or degradation) of different drugs in a municipal sewage plant, laboratory-scale tests under aerobic conditions were performed. A batch reactor containing drugs in environmentally relevant concentrations and a suspension of activated sludge was coupled online with HPLC

Rezension zu: Isabelle Stauffer: Weibliche Dandys, blickmächtige Femmes fragiles. Köln u.a.: Böhlau Verlag 2008

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Jens F. Heiderich

2009-07-01

Full Text Available Stauffer legt eine hervorragende Studie zu ironischen Inszenierungen geschlechtsspezifischer Topoi vor. Literaturgeschichtlich präzise werden die Geschlechterverwirrungen im Fin de Siècle unter besonderer Berücksichtigung der Werke Annette Kolbs und Franziska zu Reventlows kontextualisiert und mit Hilfe eines eigens entwickelten methodologischen Ansatzes analysiert. Überzeugend kann Stauffer darlegen, dass den Ironisierungen der Femme fragile und der Femme fatale, des Décadents und des Dandy die Funktion zukommt, Geschlecht als Konstruktion zu enthüllen. Avant la lettre werde dadurch Judith Butlers Theorie der subversiven Performativität bestätigt. Für die Beschreibung der damit verbundenen Konstruktionsverfahren hält Stauffer allerdings den Begriff der Ironie für treffender als den von Butler u. a. favorisierten Begriff der Parodie.

Beratung und Coaching zum Fremdsprachenlernen : Konzepte, Qualitätssicherung, praktische Erfahrungen : Beiträge zu einer Arbeitstagung (Hannover 2015)

OpenAIRE

Böcker, Jessica; Saunders, Constanze; Koch, Lennart; Langner, Michael (Hrsg.)

2017-01-01

Dieser Band entstand im Anschluss an eine Tagung zu Sprachlernberatung, die im Juli 2015 an der Leibniz-Universität Hannover stattgefunden hat. Die wesentlichen Beiträge aus drei Sektionen behandeln theoretisch-konzeptionelle Aspekte neben Fragen der Qualitätssicherung und Beispielen von good practice. Der Band gliedert sich dementsprechend in drei Bereiche: Konzepte und Forschung behandelt Fragen der Definitionen und der Konzepte zu Sprachlernberatung bzw. -coaching und ihre wissenschaft...

Wie viel muss ich wissen, um global handeln zu können? Verantwortung für Weltarmut und das Problem der epistemischen Überforderung

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Weber-Guskar Eva

2015-12-01

Full Text Available Was heißt es, sich in unserer globalisierten Welt als eine vollverantwortliche Person zu verstehen und zu verhalten? Einerseits scheint es richtig, dass wir global verantwortlich sind, d.h. dass wir auch gegen entferntes Leid etwas tun sollten; andererseits aber ist wegen vielfacher Überforderungsproblemen unklar ist, wie man diese Verantwortung tatsächlich übernehmen können soll – was wiederum dagegen spricht, dass wir diese Verantwortung berechtigtermaßen zuschreiben können. Um einen Aspekt dieses großen Themas zu behandeln, konzentriere ich mich in diesem Aufsatz auf den Anwendungsbereich von extremer Armut und argumentiere in folgenden Schritten. Zuerst spitze ich das Thema zu auf ein Problem, das Samuel Scheffler in diesem Zusammenhang konstatiert hat, nämlich einen Widerstreit zwischen dem, was Verantwortung unter den Bedingungen der Globalisierung bedeutet und dem, wie wir uns grundsätzlich als Handelnde zu verstehen gewohnt sind. Dann zeige ich erstens, dass dem Thema einer epistemischen Überforderung dabei entscheidendes Gewicht zugesprochen wird, zweitens jedoch, dass sich, genauer besehen, dieses Problem gar nicht in dieser Art stellt. Dafür schlage ich eine Analyse des Verantwortungsbegriffs vor, die es ermöglicht, Kriterien zu identifizieren, anhand derer gewisse Grenzen gezogen werden können, so dass die Zuschreibung der Verantwortung gerechtfertigt werden kann.

Experimental investigations on the mechanisms of the warm prestress effect; Experimentelle Untersuchungen zu den Mechanismen des WPS-Effekts

Energy Technology Data Exchange (ETDEWEB)

Roos, E.; Alsmann, U. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt

1998-11-01

The Government-supported, joint project by IWW Freiburg, BAM Berlin, IWW Magdeburg, and MPA Stuttgart is intended to yield insight into the mechanisms underlying the WPS, warm prestress effect, and to derive on this basis a quantitative description of the WPS effect. (orig./CB) [Deutsch] Ziel eines durch das BMBF gefoerderten Gemeinschaftsprojekts von IWW Freiburg, BAM Berlin, IWW Magdeburg und MPA Stuttgart ist es, die Mechanismen des WPS-(warm prestress)-Effekts zu erklaeren und auf dieser Basis eine quantitative Beschreibung des WPS-Effekts zu ermoeglichen. (orig./MM)

Kurz zum Klima: Zu viel Salz verdirbt den Boden

OpenAIRE

Zimmer, Markus; Lippelt, Jana; Frank, Jonas

2012-01-01

Der zunehmende Einsatz von Anlagen zur Bewässerung sowie mangelnde Erfahrungswerte und Unkenntnis über den richtigen Einsatz der künstlichen Bewässerung haben in den letzten Jahrzehnten zu einer massiven Zunahme der Versalzung des Bodens geführt. Durch diese Bodenversalzung werden weite Flächen für die Landwirtschaft unbrauchbar. Sie sind nur durch hohen Aufwand und Kosten wieder renaturierbar. Der Beitrag in der Reihe »Kurz zum Klima« gibt einen Überblick über die Versalzung in Anbaugebiet...

"Un'artefice cristiano" : Studien zu Lavinia Fontana als Historienmalerin

OpenAIRE

Schmidt, Sandra

2015-01-01

Lavinia Fontana (1552-1614) war die erste Frau, die den Beruf der Malerin professionell ausübte und sich bereits zu Lebzeiten eine beeindruckende Reputation erarbeitete. In den Quellen wird sie als „Pittora singolare tra le donne” bezeichnet und in der Tat konnte sie aufgrund ihrer zahlreichen Aufträge und Erfolge von der Kunst leben und ihre Familie ernähren, was im 16. Jahrhundert außergewöhnlich war. Auch ihr Œuvre ist ungewöhnlich umfangreich. Lavinia Fontana hinterließ ein Gesamtwerk ...

Emotional Branding in der Automobilindustrie: ein Schlüssel zu langfristigem Markenerfolg?

OpenAIRE

Nadler, Sabrina; Rennhak, Carsten

2011-01-01

In der Automobilindustrie vollzieht sich aktuell ein Wandel von der Technik- zur Kundenorientierung. Die Konsumenten sollen Produkte und Dienstleistungen nicht nur einfach nutzen, sondern eine emotionale Bindung zu ihnen aufbauen und sie im Idealfall sogar lieben. Seit Gobé (2001) werden entsprechende Markenführungsansätze mit dem Schlagwort „Emotional Branding“ bezeichnet.

Wie "zukunftsreich" ist das neue Lehramtsstudium? Bestandsaufnahme zu Medienbildung und digitalen Kompetenzen in den Curriculaentwürfen der Sekundarstufe der PädagogInnenbildung_NEU

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Klaus Himpsl-Gutermann

2015-12-01

Full Text Available Durch die PädagogInnenbildung_NEU eröffnet sich derzeit die Chance, österreichweit in vier Verbundregionen in Kooperation zwischen Universitäten und Pädagogischen Hochschulen die Lehramtsausbildung für alle Schulstufen und Schultypen zukunftsweisend zu reformieren. Zu den Ansprüchen an das neue Studium gehört auch, dass es künftige LehrerInnen an die Schulen entsendet, die neben ihrer fachlichen Expertise mit aktuellen gesellschaftlichen Herausforderungen und Entwicklungen adäquat umgehen können. Die rasant voranschreitende Technologisierung und Digitalisierung unserer Gesellschaft gehört zweifelsohne zu diesen Herausforderungen. Die E-Learning-Strategiegruppe der österreichischen Pädagogischen Hochschulen (PHELS hat deshalb die aktuell vorliegenden Curricula und Curriculaentwürfe der Sekundarstufe Allgemeinbildung in den vier Verbundregionen einer kritischen Analyse hinsichtlich Medienbildung und digitaler Kompetenzen unterzogen − mit einem ernüchternden bis verheerenden Ergebnis: Es scheint nicht nur die historische Chance vertan, Medienbildung systematisch in der LehrerInnenausbildung und damit in den Schulen zu verankern, sondern durch die fehlende informatische Grundbildung laufen künftige Generationen auch Gefahr, auf zunehmend digitalisierten Arbeitsmärkten den internationalen Anschluss zu verlieren.

The new IEA research programme on PV systems in buildings; Das neue Forschungsprogramm der internationalen Energieagentur zu Photovoltaik an Gebaeuden

Energy Technology Data Exchange (ETDEWEB)

Laukamp, H.; Erge, T. [Fraunhofer-Inst. fuer Solare Energiesysteme, Freiburg (Germany). Abt. fuer Photovoltaische Systeme und Messtechnik

1998-02-01

The International Energy Agency coordinates and supports the cooperation of OECD countries in energy politics and energy technologies by technology-oriented scientific programmes (`implementing agreements`). Under these agreements subject-oriented scientific projects (`tasks`) are carried out. Within the `Photovoltaic Power Systems Programme` the Task VII (Photovoltaics in the Built Environment) has just begun. The Fraunhofer ISE was contracted to coordinate the German contribution to Task VII and to organize information transfer to interested German institutions. So far Task VII focussed on a selection of architecturally outstanding PV buildings, on developing criteria to assess their quality and on a critical review of planned PV buildings. (orig.) [Deutsch] Die Internationale Energieagentur foerdert die Zusammenarbeit der OECD Laender in der Energiepolitik und bei den Energietechnologien, durch gemeinsam vereinbarte technologiespezifische Programme (`Implementing Agreements`). Die Programme werden durch Projekte (`Tasks`) konkretisiert. Im Programm `Photovoltaic Power Systems` wird derzeit Task VII `Photovoltaics in the Built Environment` begonnen. Das Fraunhofer ISE wurde gebeten, die deutsche Beteiligung hieran zu koordinieren und den Informationstransfer zu interessierten deutschen Firmen und Instituten zu organisieren. Schwerpunkte bisheriger Arbeiten lagen bei der Auswahl architektonisch herausragender PV-Gebaeude, bei der Erarbeitung von Kriterien zu ihrer Beurteilung und bei der kritischen Diskussion geplanter PV-Gebaeude. (orig.)

[Von den Restgütern zu den Sowchosen in Estland 1939-1953. Dokumentensammlung] / Olev Liivik

Index Scriptorium Estoniae

Liivik, Olev, 1975-

2011-01-01

Arvustus: Von den Restgütern zu den Sowchosen in Estland 1939-1953 : Dokumentensammlung / Hrsg. von David Feest, Karsten Brüggemann. Berlin : Lit Verlag, 2010. (Schriften der Baltischen historischen Kommission ; Bd. 15)

Neue Welle an IFRS: Wechseln schon bald mehr Firmen zu Swiss GAAP FER?

OpenAIRE

Sager, Marc; Vial, Jérôme

2016-01-01

Seit 2008 wechseln an der SIX kotierte Firmen vermehrt den Rechnungslegungsstandard von den IFRS zu Swiss GAAP FER (FER). Mit IFRS 9 (Finanzinstrumente), IFRS 15 (Erlöse aus Verträgen mit Kunden) und IFRS 16 (Leasingverhältnisse) werden die Anwender einmal mehr mit weitreichenden Änderungen konfrontiert.

Von eingebetteten Systemen zu Cyber-Physical Systems

Science.gov (United States)

Wedde, Rorst F.; Lehnhoff, Sebastian; Rehtanz, Christian; Krause, Olav

Das Hauptanliegen des Papiers ist, ein Paradigma für Probleme mit neuartigen Integrationsanforderungen für Forschung und Entwicklung in verteilten eingebetteten Echtzeitsystemen zu motivieren und vorzustellen, nämlich den Begriff Cyber-Physical Systems. Bei einer in letzter Zeit stark zunehmenden Anzahl von Realzeitanwendungen können ohne die Berücksichtigung solcher Forderungen keine praktisch brauchbaren Lösungen erwartet werden. Einige Anwendungsfelder werden angesprochen. Im Einzelnen werden dann für Elektroautos, die mit erneuerbaren Energien betrieben werden sollen, einerseits die Management-, verteilte Verhandlungs- und Verteilungsprobleme der benötigten Energie in einem bottom-up Ansatz gelöst. Andererseits wird als Teil unserer Projektarbeit die Bereitstellung von Reserveenergie für den allgemeinen Bedarf durch Autobatterien vorgestellt. Es zeigt sich, dass dies effizienter und wesentlich kurzfristiger in unserem verteilten Vorgehen geschehen kann als in traditionellen Verfahren.

Rezension zu: Rita Pawlowski (Hg.: „Unsere Frauen stehen ihren Mann“. Berlin: trafo Wissenschaftsverlag 2008

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Susanne Freund

2009-07-01

Full Text Available Rita Pawlowski stellt in diesem Band in alphabethischer Ordnung insgesamt 651 Frauen vor, die Abgeordnete der Volkskammer der DDR waren. Nach einer knappen Einführung zur Wahlhäufigkeit weiblicher Abgeordneter, zum Frauenanteil in der Volkskammer und in den Ausschüssen geben die Biographen im Wesentlichen Auskunft über die soziale Herkunft, die Parteizugehörigkeit, die schulische und berufliche Ausbildung und die Berufstätigkeit der einzelnen Frauen. Ziel dieses Bandes ist die Dokumentation des außergewöhnlichen Engagements von Frauen in der DDR, neben Berufstätigkeit und Familienpflichten politische Einflussmöglichkeiten zu nutzen. Damit wird ein Teilaspekt der Lebensgeschichte dieser Frauen beleuchtet, der – wie die Autorin im Vorfeld einräumt – keinen Anspruch auf Vollständigkeit erhebt. Dieser Hinweis ist wichtig, um dieses lexikalische Nachschlagewerk sinnvoll zu handhaben.

Biotechnologische Konversion von Nebenströmen der Lebensmittelindustrie zu hochwertigen Aromastoffen durch Basidiomyceten

OpenAIRE

Kunkel, Katrin

2013-01-01

29 Basidiomyceten wurden hinsichtlich der Bildung von natürlichen Aromastoffgemischen in Substrat-supplementierten Submerskulturen untersucht. Als Substrate dienten Karottenschalen, Blattspinat, Sellerietrester, Zwiebelschalen, Lauchtrester und Zitruspellets, die als Reststoffe in der lebensmittelverarbeitenden Industrie anfallen. Die Geruchseindrücke von 61 Biotransformationen wurden im Vergleich zu den Substrat- und Pilz-Blindwerten beurteilt und die Reproduzierbarkeit der ansprechendsten B...

Wybrane Aspekty Zużywania Się Połączeń Wpustowych I Wielowypustowych W Procesie Eksploatacji

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Gębura Andrzej

2014-12-01

Full Text Available W artykule przedstawiono wybrane wady połączeń wielowypustowych: mimośrodowości, przekoszenia, zwiększonych luzów. Przedstawiono znaczenie tych wad dla poprawności funkcjonowania całego zespołu napędowego. Zaprezentowano swoisty katalog tych wad w formie: wizualnego zużycia, pomiarów mechanicznych płaszczyzn przyporu, opisu matematycznego przebiegów dynamiki ruchu takiego połączenia, zobrazowań dla metod FAM-C i FDM-A. Zaznaczono skutki długotrwałej eksploatacji połączeń wielowypustowych o nadmiernym zużyciu dla bezpieczeństwa latania

Intermediale Bezugnahme und mediale Materialität Eine Replik auf Beatrice Nickels Aufsatz »Poetry gets into the city. Beobachtungen zu intermedialen Dichtungen in der Stadt«

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Johanne Mohs

2012-05-01

Full Text Available In ihrer Replik auf den Beitrag von Beatrice Nickel weitet Johanne Mohs die Perspektive auf ›Gedichtobjekte‹ im städtischen Raum nach 1945 aus. Eingangs differenziert sie den Begriff der Intermedialität, um daraufhin die von Beatrice Nickel angeführten Beispiele analytisch zu spezifizieren und interpretatorisch zu vertiefen. Letztlich folgt ihre Lesart den Avantgardekonzepten des frühen 20. Jahrhunderts, um das von den Künstlern problematisierte Wechselverhältnis von ›Kunst‹ und ›Leben‹ zu beleuchten.

Intermediale Bezugnahme und mediale Materialität. Eine Replik auf Beatrice Nickels Aufsatz »Poetry gets into the city: Beobachtungen zu intermedialen Dichtungen in der Stadt«

Directory of Open Access Journals (Sweden)

Johanne Mohs

2012-05-01

Full Text Available In ihrer Replik auf den Beitrag von Beatrice Nickel weitet Johanne Mohs die Perspektive auf ›Gedichtobjekte‹ im städtischen Raum nach 1945 aus. Eingangs differenziert sie den Begriff der Intermedialität, um daraufhin die von Beatrice Nickel angeführten Beispiele analytisch zu spezifizieren und interpretatorisch zu vertiefen. Letztlich folgt ihre Lesart den Avantgardekonzepten des frühen 20. Jahrhunderts, um das von den Künstlern problematisierte Wechselverhältnis von ›Kunst‹ und ›Leben‹ zu beleuchten.

Stille wird zu Farben : [aus "Vaikus saab värvideks" ("Stille wird zu Farben")] : [luuletused] / Jaan Kaplinski ; tlk. Irja Grönholm ja Gisbert Jänicke

Index Scriptorium Estoniae

Kaplinski, Jaan, 1941-

2006-01-01

Sisu: Stille wird zu Farben ; Der letzte rote Apfel ; Wer allein bleibt ; Ruf nach dem Vorherigen ; Mit jedem Frühling ; So viele Namen ; In die Spuren ; Höher ; Es wird Licht ; Mit dem Sommerwrind um die Wette ; Ob sie noch hört. Orig.: Vaikus saab värvideks ; Viimane verev õun ; Üksi jääb ; Hüüab eelmist ; Iga kevadega ; Niipalju nimesid ; Astub tuule jälgedele ; Käib kõrgemalt ; Saab valguseks ; Suvetuulega võidu ; Kas kuuleb enam

Rezension zu: Uta Fenske: Mannsbilder. Eine geschlechterhistorische Betrachtung von Hollywoodfilmen 1946–1960. Bielefeld: transcript Verlag 2008.

Directory of Open Access Journals (Sweden)

Asokan Nirmalarajah

2009-10-01

Full Text Available Uta Fenske beschäftigt sich in ihrer Dissertation mit den Männlichkeitsentwürfen des klassischen Hollywoodfilms der 1950er Jahre. Die Historikerin blickt damit zurück in eine Ära US-amerikanischer Geschichte, in der soziokulturelle Umbrüche zu einer Erschütterung tradierter Männlichkeitsbilder, zu einem Krisendiskurs über den modernen Mann führten. Fenskes kulturwissenschaftliche Studie kann sich dabei aus zweierlei Sicht profilieren. Zum einen erweitert sie mit der unorthodoxen Wahl ihres Untersuchungsgegenstandes das geschichtswissenschaftliche Quellenkorpus. Zum anderen kann sie durch ihren Rekurs auf eine Vielzahl von Genres zeigen, dass die Hollywoodfilme der 1950er eine größere Fülle an Antworten auf die Krise anbieten als gemeinhin angenommen.

Untersuchungen zu mummy, kette und Interaktionspartnern bei der Entwicklung des Drosophila Nervensystems

OpenAIRE

Strunk, J.M. (Judith)

2006-01-01

Die Dissertation beinhaltet genetische, funktionelle und phänotypische Analysen von Mutationen, die zu Defekten der Musterbildung des embryonalen ZNS von Drosophila melanogaster führen. Das Gen mummy wurde im Bereich 26D7 lokalisiert und codiert eine UDP-N-ACETYLGLUCOSAMIN-PYROPHOSPHORYLASE. MUMMY katalysiert eine Reaktion, deren Produkt, das UDP-N-Acetylglucosamin, Grundbaustein für Glycosylierung und GPI-Ankersynthese ist. Effekte von mummy auf diese Prozesse konnten dargestellt werden. Für...

Vom Geschäftsgang zum Prozess: Prozessmanagement in Bibliotheken am Beispiel der Staatsbibliothek zu Berlin

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Cornelia Vonhof

2015-12-01

Full Text Available Der Beitrag skizziert den Weg der Staatsbibliothek zu Berlin bei der Implementierung eines systematischen Prozessmanagements. Basierend auf den Erfahrungen aus einem Pilotprojekt werden Vorgehensweisen und Methoden reflektiert und weiterentwickelt, die sich eignen, in einer großen, arbeitsteiligen Organisation eingesetzt zu werden. Beleuchtet werden Motivationsfaktoren für Prozessmanagement sowie neue Ansätze wie Service Blueprint und Adaptiv Case Management, die das klassische Verständnis von Prozessmanagement erweitern. The article outlines the path of the Berlin State Library working towards the implementation of a systematic process management. Based on the experience of a pilot project procedures and methods are reflected and further developed to be suitable for a large, work-sharing organization. Motivating factors for process management as well as new approaches such as Service Blueprint and Adaptive Case Management, that expand the classical understanding of process management, are covered.

Potential evaluation of hydrogen peroxide for in-situ bioremediation of contaminated subsoils (chances, limitations, consequences). Final report; Untersuchung des Anwendungspotentials von Wasserstoffperoxid bei der biotechnologischen in-situ-Sanierung von kontaminierten Boeden (Moeglichkeiten, Grenzen, Folgen). Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Barenschee, E R; Weppen, P; Mueller, B G; Deckwer, W D; Muennich, K; Collins, H J

1992-06-01

Intention of this investigation was the development of methods for microbiological in situ decontamination of hydrocarbon polluted subsoils as an alternative or completion of pump and treat techniques. The changes and limitations of H{sub 2}O{sub 2} as an oxygensource was investigated on soil filled fixed bed bioreactors. The aerobic biodegradation of mineraloil products is limited by the supply of oxygen up to a conversion of 70-80%. During this state the degradation rate depends strongly on the oxygen intake rate. The degree of oxygen consumption is close to the theoretical value with regard to total mineralization and build up to biomass. At conversions higher than 70-80% the degradation rate decreases sharply due to transition from 0- to C- limitation. First attempts to increase the degradation rate by increasing the bioavailability at this state were successful. The behaviour of H{sub 2}O{sub 2} during transportation in the subsoil depends strongly on biological and physical/chemical parameters. Little remobilization of heavy metals were observed at the transition from reduced to oxidized state. (orig.) With 28 refs., 11 tabs., 34 figs. [Deutsch] Vorhabens Ziel ist die Methodenentwicklung zur mikrobiologisch unterstuetzten in-situ Dekontamination kohlenwasserstoffverunreinigter Boeden als Alternative oder Ergaenzung von hydraulischen Massnahmen. Die Moeglichkeiten und Grenzen von H{sub 2}O{sub 2} als Sauerstofftraeger werden anhand von Laborstudien mit Bodenbioreaktoren dargestellt. Der aerobe Abbau von Mineraloelprodukten ist bis zu Umsaetzen von 70-80% sauerstofflimitiert. Die Geschwindigkeit laesst sich durch die Sauerstoffeintragsrate beeinflussen. Der O{sub 2}-Nutzungsgrad liegt dabei nahe am theoretischen Wert unter Beruecksichtigung weitgehender Mineralisierung und Biomassenbildung. Bei hoeheren Umsaetzen verringert sich die Abbaugeschwindigkeit deutlich aufgrund des Uebergangs von 0- zum C-limitierten Zustand. Erste Ansaetze, die Bioverfuegbarkeit zu

Verzwickte Flussgemeinschaft - Warum es so schwierig ist, den Flüssen Raum zu geben

NARCIS (Netherlands)

Hartmann, T.

2011-01-01

Extreme Hochwasser verursachen enorme Schäden in Flusslandschaften. Flussgemeinschaften müssen künftig den Flüssen mehr Raum geben, um Hochwasser in der Fläche zurückzuhalten, statt in der Höhe (der Deiche) zu bekämpfen. Die Idee „den Flüssen mehr Raum geben“ beschreibt eigentlich etwas

Rezension zu: Yvonne Haffner, Beate Krais: Arbeit als Lebensform? Frankfurt am Main u.a.: Campus Verlag 2008

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Daniela Heitzmann

2009-07-01

Full Text Available Nachdem der Mythos des unerbittlich arbeitenden Wissenschaftlers, der sich mit Haut und Haar ‚seiner‘ Forschung verschrieben hat, langsam zu bröckeln beginnt, stellt sich aus der Genderperspektive die Frage nach der Bedeutung der Arbeitskultur für die fortbestehende Unterrepräsentanz von Frauen in der Wissenschaft, besonders in leitenden Positionen. Gleichzeitig trägt die allmähliche ‚Entdeckung‘ des Privaten für Männer, die nun auch Väter und Lebenspartner sein sollen (können, zur Entmythologisierung bei. Der vorliegende Sammelband widmet sich dem Balance-Akt zwischen Arbeits- und Privatleben, den Frauen und Männer zu leisten haben. Auf Grundlage zahlreicher empirischer Untersuchungen wird ein umfassendes und erkenntnisreiches Panorama über die Verquickungen individueller und struktureller Anforderungen an berufstätige Akademikerinnen und Akademiker vorgelegt.

Analiza wielkości i zmienności zużycia wody w kampusie Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie

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Piotr Wichowski

2015-10-01

Full Text Available W artykule przedstawiono badania wielkości i zmienności zużycia wody w kampusie SGGW w roku akademickim 2012/13. Przeciętne jednostkowe zużycie wody w okresie, kiedy realizowane są zajęcia dydaktyczne, wyniosło 29,3 dm3·d–1 dla studenta studiów stacjonarnych i 23,2 dm3·d–1 dla studenta studiów niestacjonarnych. W okresie wakacyjnym wskaźniki te są niższe i wynoszą odpowiednio 15,2 oraz 11,4 dm3·d–1. Wskaźniki te wyznaczono bez uwzględnienia zużycia wody w akademikach. Współczynnik nierównomierności dobowej dla całego kampusu wyniósł 1,54 i był zbliżony do współczynnika nierównomierności godzinowej, wynoszącego 1,52. Najwyższe miesięczne zużycie wody wystąpiło w czerwcu i było o 85% większe od najniższego, które wystąpiło w sierpniu. W cyklu tygodniowym najwyższe zużycie wody obserwowano we wtorki, a najniższe w niedziele. Przeciętne rozbiory wtorkowe są wyższe od rozbiorów niedzielnych o 31,5%. Szczyty rozbiorów w ciągu doby przypadały w godzinach 10–15 oraz 23–01.

Rezension zu: Heike Brabandt, Bettina Roß, Susanne Zwingel (Hg.: Mehrheit am Rand? Wiesbaden: VS Verlag für Sozialwissenschaften 2008

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Katja Strobel

2009-03-01

Full Text Available Im vorliegenden Sammelband werden aktuelle Diskussionen zu den Themen Globalierung, Exklusion, Geschlechterverhältnisse und Ethnizität zusammengeführt. Vor allem noch wenig rezipierte postkoloniale Ansätze werden berücksichtigt. Das breite Spektrum an Themen und die Vielfalt an Ansätzen, die von empirischen Studien zur Makroökonomik über historische Analysen bis hin zu detaillierten Fallstudien reicht, überzeugt. Der Anspruch, zum Thema globale Ungleichheit Beiträge aus den zentralen sozialwissenschaftlichen Feldern sinnvoll zusammenzuführen, wird eingelöst.

Rezension zu: Christina Holtz-Bacha (Hg.: Frauen, Politik und Medien. Wiesbaden: VS Verlag für Sozialwissenschaften 2008

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Tanja Maier

2009-03-01

Full Text Available In dem von Christina Holtz-Bacha herausgegebenen Sammelband wird aus einer kommunikationswissenschaftlichen Perspektive untersucht, wie Politikerinnen in höchsten politischen Ämtern medial repräsentiert werden. In den einzelnen Beiträgen wird der Frage nachgegangen, ob die zunehmende Sichtbarkeit von Politikerinnen wie Angela Merkel, Christina Kirchner oder Ségolène Royal auch zu einer veränderten medialen Berichterstattung geführt habe. Analysiert werden nicht nur die mediale Präsenz von Politikerinnen im Vergleich zu ihren männlichen Kollegen, sondern auch die Gemeinsamkeiten und Unterschiede in den textuellen und bildlichen Darstellungsweisen. Der Band liefert aus der Perspektive der politischen Kommunikationsforschung einige interessante empirische Einzelanalysen. Die theoretische Auseinandersetzung mit Konzepten der Geschlechterforschung spielt nur am Rande eine Rolle.

Chromatography.

Science.gov (United States)

Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

Philosophisch und theologisch denken (lernen. Fachdidaktische Skizzierungen zu einer ReligionslehrerInnenbildung NEU

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Philipp Klutz

2013-10-01

Full Text Available ENGLISH: It is an essential challenge for (religious teachers to initiate successful learning at school. How teachers act in their instruction is a key factor for successful learning at school. So teacher education has to focus on the process of professionalization of teachers. The faculty of Catholic Theology at the University of Vienna realigns the courses of subject didactic. According to the course ‘Philosophisch und theologisch denken’ this paper illustrates the students’ process of professionalization. The aim of this process is to form a ‘habitus’ in which religious education at schools and subject didactic (didactic of RE is visible under a theological approach. GERMAN: Wie gelingendes Lernen an der Schule initiiert werden kann, ist eine zentrale Herausforderung von (Religions LehrerInnen. Dabei kommt der Qualität des unterrichtlichen Handelns von Lehrpersonen eine entscheidende Rolle zu. In der Ausbildungsphase von ReligionslehrerInnen gilt es, sich dem Prozess der Professionalisierung zu widmen. An der Katholisch-Theologischen Fakultät der Universität Wien wird die fachdidaktische Lehre neu ausgerichtet, die sich so den Herausforderungen des Religionslehrberufs stellt. Anhand des fachdidaktischen Seminars ‚Philosophisch und theologisch denken‘ wird der Professionalisierungsprozess von Studierenden aufgezeigt. Durch diesen soll eine Haltung (Habitus ausgebildet werden, der eine theologisch begründete Sichtweise religiöser Bildung an der Schule und somit von Fachdidaktik (Religionsdidaktik sichtbar werden lässt.

Das Re-entry von Kritik: Assemblageforschung nach der Kritik an der Kritik. Kommentar zu Alexa Färbers „Potenziale freisetzen“

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Hanna Göbel

2014-05-01

Full Text Available Der Kommentar zum Beitrag von Alexa Färber diskutiert eine Vermengung von drei unterschiedlichen Kritikbegriffen sowie Orten von Kritik in der aktuellen Debatte um die Assemblageforschung im Feld der Urban Studies. Ich rekonstruiere und unterscheide zwischen einem Kritikbegriff als theoretischer Norm, wie er von der (neo-marxistischen Stadt- und Raumforschung vertreten wird, und der ontologischen Kritik dieser Norm seitens der Assemblageforscher_innen. Alexa Färbers Beitrag zeigt drittens exemplarisch eine sich einschleichende normative Ebene in der Assemblageforschung auf, die bislang als Kritikform unterbelichtet geblieben ist. Diese wird als Wiedereinführung (re-entry von empirisch vollzogener Kritik in die Assemblageforschung bezeichnet. Damit ist eine theoretische Neupositionierung von Kritik ‚innerhalb’ einer Assemblage gemeint, indem Kritik nicht mehr als theoretische Norm ‚außerhalb’ zu verorten ist. In diesem Kommentar plädiere ich dafür, in der Assemblageforschung eine differenzierte Auseinandersetzung mit unterschiedlichen Begriffen und Orten von Kritik zu pflegen, um innerhalb der Urban Studies und für interessierte städtische Akteure mit urbaner Expertise (u.a. Architekt_innen, Planer_innen, Künstler_innen, Aktivist_innen, Kultur- und Sozialarbeiter_innen, DIY-Gemeinschaften klarer adressierbar zu sein.

Gefährlicher Trend : Smartphone im Strassenverkehr : auch zu Fuss ist das Ablenkungspotenzial sehr gross.

NARCIS (Netherlands)

2016-01-01

Viele Menschen, die sich zu Fuß im Straßenverkehr bewegen, nutzen dabei das Smartphone. Dies ist das Ergebnis einer Erhebung von DEKRA in sechs europäischen Hauptstädten. Von den rund 14.000 erfassten Personen nutzten fast 17 Prozent ihr Handy — für Textnachrichten, zum Telefonieren oder Musikhören.

Ideen zu einer Literatursoziologie des Internets. Mit einer Blogotop-Analyse

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Peer Trilcke

2013-11-01

Full Text Available Der Essay skizziert und exemplifiziert die Möglichkeiten einer Literatursoziologie des Internets und plädiert in diesem Zusammenhang für eine Empirisierung der Forschung zu diesem rasant wachsenden, jedoch bisher in seiner Differenziertheit allenfalls oberflächlich beschriebenen Feld der Kommunikation über Literatur. Hierzu werden die literaturwissenschaftlichen Internet Studies und ihr literatursoziologischer Teilbereich innerhalb der allgemeinen Digital Humanities verortet. Als Beispiel für eine in diesem Sinne relational-empirische Literatursoziologie des Internets werden erste Ergebnisse der Analyse eines sog. Bücherblogotops präsentiert, anhand derer sich einige Mechanismen der sekundären literarischen Kommunikation zwar nicht repräsentativ, aber doch exemplarisch diskutieren lassen.

Essay (with abstract in English Drei Avantgarde-Strömungen des heutigen US-Geisteslebens – und ihre Beziehung zu Europa

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Roland Benedikter

2006-12-01

Full Text Available Die heutigen USA gelten vielen als Vorreiter auf dem Weg zur integrativen Erneuerung von Wissenschafts- und Erkenntnisparadigmen. Dies vor allem im Bereich der traditionellen Kern- und Grundlagen-Wissenschaft der neuzeitlichen Universität: der Philosophie und der historisch aus ihr erwachsenen Psychologien. Seit einigen Jahren ist in den USA in der Tat eine Entwicklung im Gang, welche die Einseitigkeiten des nominalistisch-subjektivistischen Paradigmas der „Postmoderne“, welches aus ideengeschichtlicher Sicht die Epoche zwischen 1979 und 2001 geprägt hat, um einen neuen geistigen Objektivismus ausgleichen und beide zu einem neuen, „subjektiv-objektiven“ Paradigma integrieren will. Diese Entwicklung findet ihren Ausdruck in drei exemplarischen Avantgarde-Strömungen, die im vorliegenden Beitrag vorgestellt sowie auf Charakteristiken und Wechselbeziehungen untersucht werden. Dabei erweist sich, dass die heutige ideengeschichtliche Avantgarde der USA in Kernterminologie, historischer Kontinuität und Ausrichtung stark pazifisch-asiatisch, aber noch zu wenig atlantisch-europäisch geprägt ist. Das scheint mit ein Grund dafür zu sein, warum diese Avantgarde-Ansätze trotz ihres hochwertigen Anregungs- und Innovations-Potentials im Hinblick auf ein ganzheitliches Wissenschafts-Paradigma für das 21. Jahrhundert noch unübersehbare Schwierigkeiten haben, den atlantisch-europäisch geprägten Hauptstrom des Geistes-, Kultur- und politisch-sozialen Lebens ihrer Gesellschaft zu erreichen. Es zeigt sich, dass der innere Ausgleich zwischen pazifischen und atlantischen Ideen-Einflüssen eine der zentralen Herausforderungen für diese Avantgarde-Strömungen, aber darüber hinaus im Spiegelverhältnis auch für das europäische Kultur- und Gesellschafts-Paradigma sowie für die Entwicklung der integralen Bewegungen auf Weltebene insgesamt ist.

Alte Thesen neu gelesen: Perspektiven kritischer Stadtforschung. Kommentar zu Hartmut Häußermann & Walter Siebels „Thesen zur Soziologie der Stadt“

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Carsten Keller

2013-07-01

Full Text Available [Dieser Artikel ist Teil einer Debatte] Der Text „Thesen zur Soziologie der Stadt“ scheint mir besonders in den abschließend formulierten Perspektiven, die Hartmut Häußermann und Walter Siebel unter der Überschrift „Aufgaben einer kritischen Soziologie der Stadt“ formulieren, nach wie vor lesenswert und aktuell zu sein. Drei Perspektiven werden hier aufgezeigt: erstens eine Wissenschafts- und Ideologiekritik, zweitens eine empirisch orientierte Zustandsbeschreibung städtischer Strukturen und von Stadtentwicklung sowie drittens eine Analyse der staatlichen Stadtpolitik. Diese drei abschließenden Perspektiven möchte ich im Folgenden kommentieren. Es wird mithin keine immanente Auseinandersetzung mit dem gesamten Text und weiteren Arbeiten der beiden Autoren angestrebt. Es hätte mich zwar durchaus gereizt, die Entwicklung der Arbeiten von Häußermann und Siebel vor dem Hintergrund dieses frühen, emphatisch formulierten Textes zu reflektieren. Vielleicht auch wegen der persönlichen Bekanntschaft mit Häußermann, den ich als Projekt- und Dissertationsbetreuer an der Humboldt-Universität kennenlernte, erschien mir eine solche Zugangsweise zu den „Thesen“ durchaus naheliegend. [...

Intertextuelle und intramediale Bezüge als Orientierungsangebot – systematische Überlegungen und exemplarische Untersuchungen zu Verweisen auf das Fernsehangebot

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Ben Bachmair

2017-07-01

Full Text Available Auch wenn das Internet sich weder so schnell noch so nachhaltig im Alltag und als Bestandteil von Massenkommunikation etablierte, wie es Ende der neunziger Jahre den Anschein hatte, so zeigt sich am Internet doch, was sich mit der Vernetzungs- und Verfügbarkeitslogik verändern könnte, die dem Internet zu eigen ist. Manuel Castells (2001 mit seiner Analyse des „Informationszeitalters“ und der als instrumentellem Netzwerk organisierten Gesellschaft skizziert die Umrisse, wie sich unsere Gesellschaft mit welcher Dynamik entwickelt. Er spricht von einer „informationeilen Entwicklungsweise“ (ebd., S. 17, die anders als die „agrarische“ oder die „industrielle“ auf das gesellschaftliche Verhältnis der Menschen zur Natur („Produktion“, zu sich selber („Erfahrung“, „kulturelle Identität“ und zu anderen (.Macht“ einwirkt. Einen Aspekt dieser „informationellen Entwicklungsweise“ beschreibt Castells mit dem Hinweis auf „globale Netzwerke der Instrumentalität“, die eine „unüberschaubare Anzahl virtueller Gemeinschaften“ hervorbringt (ebd., S. 23. Dabei konstituiert sich auch eine Art von Subjektivität, die sich im Moment als „zunehmende Distanz zwischen Globalisierung und Identität, zwischen dem Netz und dem Ich“ beschreiben lässt (ebd., S. 24. In dieser Spannung bekommt .Multimedia“ die Funktion einer „symbolischen Umwelt“ (ebd., S. 415.

ALBA, organisation interaméricaine ou vénézuélienne ?

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Jean-Jacques Kourliandsky

2011-01-01

Full Text Available L’«Alliance Bolivarienne des peuples de notre Amérique», ou ALBA, est de toutes les organisations interaméricaines celle dont l’identité est la plus originale. S’affirmant anti-impérialiste elle donne en effet à l’idéologie une place centrale qui commande la coopération entre ses membres. Mais l’ALBA au quotidien diffère-t-elle d’autres organisations d’intégration ? Le lien entre les différents pays qui la composent n’est-il pas au-delà de l’hommage unanime rendu à Bolivar bien davantage celui de pouvoir bénéficier du pétrole vénézuélien à un prix préférentiel ? L’ALBA, comme d’autres institutions latino-américaines, ne répond-elle pas à l’ambition d’un État, en l’occurrence ici le Venezuela, plus qu’à celle de construire un projet collectif pérenne? Ce lien entre le pétrole de son initiateur vénézuélien et l’ALBA, est une garantie pour le présent. Mais l’ALBA survivrait-elle à une alternance politique au Venezuela, ou à une chute des prix du baril affectant le nerf de l’organisation ?

Auf dem Weg zu semantischen APIs für Forschungsdatendienste

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Anna Fensel

2017-09-01

Full Text Available Die schnelle Entwicklung der Internet- und Web-Technologie verändert den Stand der Technik in der Kommunikation von Wissen oder  Forschungsergebnissen. Insbesondere werden semantische Technologien, verknüpfte und offene Daten zu entscheidenden Faktoren für einen  erfolgreichen und effizienten Forschungsfortschritt. Zuerst definiere ich den Research Data Service (RDS und diskutiere typische aktuelle  und mögliche zukünftige Nutzungsszenarien mit RDS. Darüber hinaus bespreche ich den Stand der Technik in den Bereichen semantische Dienstleistung und Datenanmerkung und API-Konstruktion sowie infrastrukturelle Lösungen, die für die RDS-Realisierung anwendbar sind. Zum Schluss werden noch innovative Methoden der Online-Verbreitung, Förderung und effizienten Kommunikation der Forschung diskutiert.

Declining price difference from gas to coal provides for a new situation in the electricity market; Sinkende Preisdifferenz von Gas zu Kohle sorgt fuer neue Lage am Strommarkt

Energy Technology Data Exchange (ETDEWEB)

Anon.

2017-01-15

The price difference (spread) between power coal and natural gas has increased sharply since 1999. This gap reached its peak in 2013 with 171 Euro/t SKE. In many cases, higher CO{sub 2} prices were required to promote gas use in the electricity sector. However, it has now become clear that falling gas prices lead to a growing competitiveness of natural gas. Interventions in the EU-ETS or at the national level with the aim to promote gas use in the electricity sector do not make sense and would merely reduce the competitive pressure on the gas producers and lead them to become a monopoly rents. [German] Der Preisabstand (Spread) zwischen Kraftwerkskohle und Erdgas stieg seit 1999 stark an. Dieser Gap erreichte in 2013 mit 171 Euro/t SKE seinen Hoechststand. Vielfach wurden hoehere CO{sub 2}-Preise gefordert, um den Gaseinsatz im Stromsektor zu foerdern. Doch inzwischen zeigt sich, dass fallende Gaspreise zu einer wachsenden Wettbewerbsfaehigkeit von Erdgas fuehren. Interventionen in das EU-ETS oder auf nationaler Ebene mit dem Ziel, den Gaseinsatz im Stromsektor zu foerdern, machen daher keinen Sinn und wuerden lediglich den Wettbewerbsdruck auf die Gasproduzenten mindern sowie fuer diese zu einer Monopolrente fuehren.

„Dichtes Verstehen“ als Schritt zu einer begegnenden Bibliothekskultur

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Barbara Schellhammer

2013-11-01

Full Text Available Mit seiner ethnografischen Methode der dichten Beschreibung schlug der amerikanische Sozial­wissenschaftler Clifford Geertz eine völlig neue Richtung in der Kulturanthropologie ein. Diese sogenannte „interpretative Wende“ stellt auch jenseits der Ethnografie eine grosse Bereicherung dar. Überall wo Men­schen unterschiedlicher sozio-kultureller Herkunft aufeinander treffen, eignet sich die dichte Beschreibung, um kulturelle Bedeutungssysteme besser verstehen und einordnen zu können. Dies hilft nicht nur im Be­reich der qualitativen Sozialforschung, sondern auch ganz konkret im alltäglichen Leben, im privaten, wie auch im beruflichen Umgang mit fremden Erfahrungshorizonten. Denn die dichte Beschreibung sprengt vorgefertigte, „dünne“, sozio-kulturelle Typologien und Etikettierungen. Sie möchte vielmehr kulturelle Symbole auf deren tiefe Bedeutung phänomenologisch beschreiben und hermeneutisch ergründen. Diese Fähigkeit kann gerade auch im Umgang mit Kundinnen und Kunden im Bibliotheksbereich eine grosse Be­reicherung darstellen und dazu beitragen, eine positive Bibliothekskultur zu begründen. With his ethnographic approach Clifford Geertz established a new way of thinking and doing re­search in cultural anthropology. This so called “ethnographic turn” continues to be of great significance for many disciplines, not only for ethnological studies. Wherever people of different socio-cultural back­grounds meet, Geertz's method of “Thick Description” helps to understand foreign cultures, or, what Geertz calls “complex systems of meaning-making”. This is important for scientific research settings, but also for day-to-day encounters in multi-cultural societies in a globalized world. “Thin” forms of describing other­ness categorize, stereotype or come up with set explanations which will never be able to grasp the complex­ity and ever changing nature of peoples and cultures. Geertz's method seeks to (1 thoroughly

Zum Entwicklungsstand und zu Entwicklungsproblemen unserer Jugend - 1987 : Forschungsergebnisse - Beobachtungen - Überlegungen in 10 Thesen

OpenAIRE

Friedrich, Walter

1987-01-01

Dieser Bericht gibt in zehn Thesen einen Überblick über Forschungsergebnisse, Beobachtungen und Überlegungen zum Entwicklungsstand der DDR-Jugend im Jahre 1987. Diese sei "in ihrer großen Mehrheit durch ein hohes Niveau ihrer sozialistischen Persönlichkeitsentwicklung charakterisiert". Kritisiert wird die Rolle der FDJ, die die Interessenvertretung der Jugend nicht ausreichend wahrnehme. Weiterhin nehme die Rezeption westlicher Rundfunk- und Fernsehsendungen immer mehr zu, jedoch sei es verbo...

Alle Wege führen nach Rom: Trifft dies auch für die Veränderungsmessung zu?

DEFF Research Database (Denmark)

Boecker, Maren; Volz-Sidiropoulou, Eftychia; Nielsen, Tine

Die Erfassung von Veränderungen mithilfe von Fragebögen spielt eine wichtige Rolle in der klinischen Praxis und Forschung. Ziel dieser Studie war es zu untersuchen, ob im Rahmen der Veränderungsmessung die verwendete Datenanalysemethode einen Einfluss auf die Studienergebnisse hat. Insbesondere w...

Die Erforschung kollektiver und individueller Dynamik – Zu einer historisch und prozess-soziologisch orientierten interpretativen Sozialforschung

Directory of Open Access Journals (Sweden)

Gabriele Rosenthal

2016-04-01

Full Text Available In diesem Beitrag konzentriere ich mich auf die Vorteile einer konsequent durchgeführten interpretativen oder rekonstruktiven Sozialforschung gegenüber anderen qualitativen Verfahren und verdeutliche, inwiefern wir diese Vorteile noch konsequenter verfolgen können als bisher. Dabei stellen sich die folgenden Fragen: Was können wir mit wenigen, aber aufwendigen Fallrekonstruktionen mit dem Ziel einer "theoretischen Verallgemeinerung" am Einzelfall im Unterschied zu qualitativen Verfahren mit umfangreichen Stichproben leisten, die eher eine numerische oder quantitative Verallgemeinerung zum Ziel haben? Inwiefern kommen wir damit überhaupt zu "allgemeinen" Aussagen über die soziale (kollektive und individuelle Wirklichkeit, über eine bestimmte Gruppierung, Organisation oder Ortsgemeinde, einen kollektiver Konflikt, ein bestimmtes Milieu oder soziales Netzwerk? Bei der Behandlung dieser Fragen geht es mir vor allem um ein Plädoyer für eine methodisch stärker historisch und prozess-soziologisch orientierte interpretative Sozialforschung. M.E. liegen in einer konsequenten Rekonstruktion der Verläufe und Wandlungsprozesse von einzelnen "Fällen" und ihrer Verflechtungen mit anderen "Fällen" die Chancen für eine wirklich empirisch geerdete Theorieentwicklung. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1602139

Analyse der Literatur zu Klimawirkungen in Deutschland: ein Gesamtbild mit Lücken

Science.gov (United States)

Fleischhauer, Mark; Greiving, Stefan; Lindner, Christian; Lückenkötter, Johannes; Schauser, Inke

Dieses Kapitel präsentiert Ergebnisse einer umfassenden Literaturauswertung zu relevanten Klimawirkungen für Deutschland, die im Rahmen des Projekts "Netzwerk Vulnerabilität" vorgenommen wurde. Es zeigt auf, dass ein aggregiertes Gesamtbild der Klimawirkungen für Deutschland als Grundlage für Folgenabschätzungen und Anpassungsplanungen noch nicht gezeichnet werden kann, da eine große Bandbreite an Ansätzen zur Bewertung von Vulnerabilitäten oder Klimawandelfolgen existiert und die gegenwärtig vorhandenen Klimawirkungs- und Vulnerabilitätsstudien von großer Heterogenität gekennzeichnet sind. Als erster Schritt wird deshalb eine Zusammenschau bereits vorhandener Ansätze geliefert.

Für Forschung und Kultur - Öffentlichkeitswirksame Darstellung bibliothekarischer Weltschätze und bibliothekarischer Wissenschaftsservices am Beispiel der Staatsbibliothek zu Berlin

Directory of Open Access Journals (Sweden)

Barbara Schneider-Kempf

2014-12-01

Full Text Available Die Öffentlichkeitsarbeit der Staatsbibliothek zu Berlin zielt auf eine wirksame Darstellung ihrer bibliothekarischen Weltschätze und ihrer Serviceangebote für die Wissenschaft ab. Sie ruht auf drei Säulen: kulturelle Breitenbildung für wenig bibliotheksaffine Kreise, allgemeine und breit gefächerte Öffentlichkeitsarbeit sowie Aktionen, die sich an spezielle communities in der Wissenschaft richten. Der Beitrag informiert auch über die erfolgreiche Umsetzung dieser Strategie anhand zahlreicher Beispiele. Er zeigt, wie es der Staatsbibliothek in der Hauptstadt Berlin, in der viele Gedächtnisinstitutionen tätig sind, gelingt, öffentlich präsent zu bleiben und ihr Profil zu vermitteln. The public relations work of the Berlin State Library – Prussian Cultural Heritage aims at effectively presenting its globally significant treasures as well as its services for the scientific world. It is based on three pillars: cultural education for the general public, especially for people who are not naturally close to libraries; a general and wide variety of public relations work; and events which target special communities in science. The paper also presents many examples for the effectual implementation of this strategy. It shows how the State Library, in the capital city of Berlin with its many memory institutions, succeeds in keeping a strong presence and communicating its profile to the public.

Plasma chromatography

International Nuclear Information System (INIS)

Anon.

1984-01-01

This book examines the fundamental theory and various applications of ion mobility spectroscopy. Plasma chromatography developed from research on the diffusion and mobility of ions. Topics considered include instrument design and description (e.g., performance, spectral interpretation, sample handling, mass spectrometry), the role of ion mobility in plasma chromatography (e.g., kinetic theory of ion transport), atmospheric pressure ionization (e.g., rate equations), the characterization of isomers by plasma chromatography (e.g., molecular ion characteristics, polynuclear aromatics), plasma chromatography as a gas chromatographic detection method (e.g., qualitative analysis, continuous mobility monitoring, quantitative analysis), the analysis of toxic vapors by plasma chromatography (e.g., plasma chromatograph calibration, instrument control and data processing), the analysis of semiconductor devices and microelectronic packages by plasma chromatography/mass spectroscopy (e.g., analysis of organic surface contaminants, analysis of water in sealed electronic packages), and instrument design and automation (hardware, software)

Drei Avantgarde-Strömungen des heutigen US-Geisteslebens – und ihre Beziehung zu Europa

Directory of Open Access Journals (Sweden)

Roland Benedikter

2006-12-01

Full Text Available Zusammenfassung: Die heutigen USA gelten vielen als Vorreiter auf dem Weg zur integrativen Erneuerung von Wissenschafts- und Erkenntnisparadigmen. Dies vor allem im Bereich der traditionellen Kern- und Grundlagen-Wissenschaft der neuzeitlichen Universität: der Philosophie und der historisch aus ihr erwachsenen Psychologien. Seit einigen Jahren ist in den USA in der Tat eine Entwicklung im Gang, welche die Einseitigkeiten des nominalistisch-subjektivistischen Paradigmas der „Postmoderne“, welches aus ideengeschichtlicher Sicht die Epoche zwischen 1979 und 2001 geprägt hat, um einen neuen geistigen Objektivismus ausgleichen und beide zu einem neuen, „subjektiv-objektiven“ Paradigma integrieren will. Diese Entwicklung findet ihren Ausdruck in drei exemplarischen Avantgarde-Strömungen, die im vorliegenden Beitragvorgestellt sowie auf Charakteristiken und Wechselbeziehungen untersucht werden. Dabei erweist sich, dass die heutige ideengeschichtliche Avantgarde der USA in Kernterminologie, historischer Kontinuität und Ausrichtung stark pazifisch-asiatisch, aber noch zu wenig atlantisch-europäisch geprägt ist. Das scheint mit ein Grund dafür zu sein, warum diese Avantgarde-Ansätze trotz ihres hochwertigen Anregungs- und Innovations-Potentials im Hinblick auf ein ganzheitlichen Wissenschafts-Paradigma für das 21. Jahrhundert noch unübersehbare Schwierigkeiten haben, den atlantisch-europäisch geprägten Hauptstrom des Geistes-, Kultur- und politisch-sozialen Lebens ihrer Gesellschaft zu erreichen. Es zeigt sich, dass der innere Ausgleich zwischen pazifischen und atlantischen Ideen-Einflüssen eine der zentralen Herausforderungen für diese Avantgarde-Strömungen, aber darüber hinaus im Spiegelverhältnis auch für das europäische Kultur- und Gesellschafts-Paradigma sowie für die Entwicklung der integralen Bewegungen auf Weltebene insgesamt ist. Three avant-garde currents within the contemporary intellectual life in the United States

Cromatografia unificada Unified chromatography

Directory of Open Access Journals (Sweden)

Carin von Mühlen

2004-10-01

Full Text Available The scope of this study encompasses an overview of the principles of unified chromatography as well as the principles of chromatographic techniques as applied to unified systems, which include gas chromatography, liquid chromatography, supercritical fluid chromatography, high temperature and high pressure liquid chromatography, micro-liquid chromatography, enhanced fluidity chromatography, and solvating gas chromatography. Theoretical considerations and individual instrumental parameters such as mobile phase, sample introduction system, columns, and detection system are also discussed. Future applications of this separation approach are discussed.

Social Entrepreneurship im etablierten Wohlfahrtsstaat : Aktuelle empirische Befunde zu neuen und alten Akteuren auf dem Wohlfahrtsmarkt

OpenAIRE

Heinze, Rolf G.; Schönauer, Anna-Lena; Schneiders, Katrin; Grohs, Stephan; Ruddat, Claudia

2013-01-01

Im internationalen Vergleich hat sich die wissenschaftliche Diskussion um die gesellschaftliche Relevanz des Phänomens „Social Entrepreneurship“ (SE) in Deutschland relativ spät entwickelt. In Asien wurde die Debatte insbesondere durch die von Muhammad Yunus 1983 gegründete Grameen Bank angestoßen und spätestens seit der Auszeichnung Yunus‘ mit dem Friedensnobelpreis wird SE in vielen Nationen zunehmend als Chance wahrgenommen, soziale Missstände effektiv und nachhaltig zu bekämpfen....

Geschlecht zwischen Körper und Konstruktion: Aktuelle Impulse zu einer langen Debatte Between Bodies and Constructions: Current Takes on a Long-Standing Debate

Directory of Open Access Journals (Sweden)

Natascha Gruber

2002-11-01

Full Text Available Die mit dem Erscheinen von Judith Butlers Unbehagen der Geschlechter ausgelöste „Essentialismus versus Konstruktivismus“-Debatte um die Frage, wie Materialität und Körper zu denken sei, hält die Geschlechterforschung bis heute in dilemmatischer Spannung. Kann auf die Kategorie Geschlecht überhaupt verzichtet werden? Der Sammelband Verhandlungen des Geschlechts dokumentiert anhand von 15 Beiträgen aus den Bereichen Kulturwissenschaften, Philosophie, Psychoanalyse und Politik die aktuelle Entwicklung der Debatte rund um den an Butler orientierten feministischen Konstruktionsbegriff. Unter Rückgriff auf unterschiedliche Ansätze wird versucht, zwischen „Körper“ und „Diskurs“ zu vermitteln und Materialität neu zu denken.The “essentialism-versus-constructivism” debate which was sparked by Butler’s work, Gender Trouble, a debate centered around the question how to best think about materiality and bodies, continues to be relevant to gender studies to the present day. Is it at all possible to avoid gender as a category? 15 essays from scholars in cultural studies, philosophy, psycho-analysis, and politics document the current development of the debates that were inspired by Butler’s ideas about feminist constructions. Using a variety of different approaches, the authors attempt to mediate between the concepts of “body” and “discourse” and to conceive of materiality in a new way.

Emotions as a site-related factor. The attitudes of the population towards energy policy and environmental protection; Emotionen als Standortfaktor. Die Einstellungen der Bevoelkerung zu Energiepolitik und Umweltschutz

Energy Technology Data Exchange (ETDEWEB)

Koecher, R. [Inst. fuer Demoskopie, Allensbach (Germany)

1997-06-01

For years, debate has been raging on the future competitiveness of Germany. The discussions focus on wages and incidental wage costs, working hours, the education and training system, technological changes, flexibilization and the fight against red tape as well as social consensus. But one site-related factor hardly crops up in public discussion and in economic-science textbook and expertises, although it quite essentially influences competitiveness, now even more than formerly: the mentality of the population. It includes priorities held by society, target concepts such as the openness of the population towards innovation and its attitude towards technology and technical progress as well as the way in which discussions are conducted in society and decisions taken, especially also people`s inclination to rationality or irrationality, and proneness to emotions or ideological thinking. (orig.) [Deutsch] Seit Jahren wird ueber die Zukunft des Standortes Deutschland diskutiert und gestritten. Im Mittelpunkt der Diskussion stehen Loehne und Lohnnebenkosten, Arbeitszeiten, das Bildungs- und Ausbildungssystem, technologische Veraenderungen, Flexibilisierung und Entbuerokratisierung und der soziale Frieden. Ein Standortfaktor kommt dagegen in der oeffentlichen Diskussion wie auch in den wirtschaftswissenschaftlichen Lehrbuechern und Expertisen kaum vor, obwohl er die Standortqualitaet ganz wesentlich beeinflusst, heute noch mehr als frueher: Die Mentalitaet der Bevoelkerung. Dazu gehoeren die gesellschaftlichen Prioritaeten und Zielvorstellungen wie die Innovationsoffenheit der Bevoelkerung, ihre Einstellung zu Technik und technischem Fortschritt wie die Art, gesellschaftliche Diskussionen zu fuehren und Entscheidungen zu treffen, besonders auch die Neigung zu Rationalitaet und Irrationalitaet, die Anfaelligkeit fuer Emotionen und Ideologisierung. (orig.)

[Antjekathrin Grassmann. Zu den wirtschaftlichen und persönlichen Beziehungen Lübecks ins Baltikum im Lichte einer unbeachteten mittelalterlichen Quellegruppe]/ Dennis Hortmuth

Index Scriptorium Estoniae

Hormuth, Dennis

2012-01-01

Arvustus: Antjekathrin Grassmann. Zu den wirtschaftlichen und persönlichen Beziehungen Lübecks ins Baltikum im Lichte einer unbeachteten mittelalterlichen Quellegruppe. In: Leder ist Brot. Beiträge zur norddeutschen Landes- und Archivgeseten. Schwerin 2011. S. 125-135

Chromatography resin support

Science.gov (United States)

Dobos, James G.

2002-01-01

An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

ILK statement on the recommendations by the working group on procedures for the selection of repository sites; ILK-Stellungnahme zu den Empfehlungen des Arbeitskreises Auswahlverfahren Endlagerstandorte Internationale (AkEnd)

Energy Technology Data Exchange (ETDEWEB)

Anon.

2003-11-01

The Working Group on Procedures for the Selection of Repository Sites (AkEnd) had been appointed by the German Federal Ministry for the Environment (BMU) to develop procedures and criteria for the search for, and selection of, a repository site for all kinds of radioactive waste in deep geologic formations in Germany. ILK in principle welcomes the attempt on the part of AkEnd to develop a systematic procedure. On the other hand, ILK considers the two constraints imposed by BMU inappropriate: AkEnd was not to take into account the two existing sites of Konrad and Gorleben and, instead, work from a so-called white map of Germany. ILK recommends to perform a comprehensive safety analysis of Gorleben and define a selection procedure including the facts about Gorleben and, in addition, to commission the Konrad repository as soon as possible. The one-repository concept established as a precondition by BMU greatly restricts the selection procedure. There are no technical or scientific reasons for such concept. ILK recommends to plan for separate repositories, which would also correspond to international practice. The geoscientific criteria proposed by AkEnd should be examined and revised. With respect to the site selection procedure proposed, ILK feels that procedure is unable to define a targeted approach. Great importance must be attributed to public participation. The final site selection must be made under the responsibility of the government or the parliament. (orig.) [German] Der Arbeitskreis Auswahlverfahren Endlagerstandorte (AkEnd) hat Ende 2002 seine Empfehlungen vorgestellt. Der AkEnd war vom Bundesumweltministerium (BMU) berufen worden, um Verfahren und Kriterien fuer die Suche und die Auswahl eines Endlagerstandortes fuer alle Arten radioaktiver Abfaelle in tiefen geologischen Formationen in Deutschland zu entwickeln. Die ILK begruesst grundsaetzlich den Versuch des AkEnd, ein systematisches Verfahren zu entwickeln. Allerdings haelt die ILK die beiden vom BMU

Cyborg oder Göttin: Wie Technikforscherinnen ihr Verhältnis zu Technik sehen

Directory of Open Access Journals (Sweden)

Ulrike Kissmann

2001-11-01

Full Text Available Die Autorinnen haben für die Beiträge eigene auto/biographische Erlebnisse ausgewählt, in denen der mediale Charakter von Technik deutlich wird. Die Geschichten erzählen also von Technik, die soziale Ordnung und Bedeutung vermittelt und auf diese Weise dazu beiträgt, Geschlechtergrenzen und andere Grenzen wie die zwischen „bekannt“ und „fremd“ oder „normal“ und „anormal“ herzustellen. Die Auto/Biographien sind durch Technik einerseits fremdbestimmt, andererseits zeigen die Autorinnen auch, wie Selbstbestimmung über diese Grenzen hinweg möglich ist. Sie benutzen Donna Haraways Cyborg Metapher (1985, um das Selbst in der Verflechtung von Sozialem und Technischem auto/biographisch zu rekonstruieren.

Die Übung an sich selbst außerhalb der Ästhetik: das Gegenmittel zu Instrumentalisierungen der Kultur.

Directory of Open Access Journals (Sweden)

Stanislas d’Ornano

2005-10-01

Full Text Available In heutiger Zeit den politischen Status der Kultur und der Kunst zu untersuchen setzt voraus, dass man ebenfalls drei Aspekte unserer Epoche in Betracht zieht. Wir haben die Orientierung verloren aufgrund des Widerspruchs zwischen der Vielfalt der Wege (Theorien, Lebensstile, Kunstrichtungen einerseits und der Vorstellung der Erreichung eines Ziels (das Ende der Geschichte, die vollkommene Gesellschaft andererseits. Wir erleben täglich die Situation einer zweifachen Instrumentalisierung, ...

Hydroxylapatite chromatography.

Science.gov (United States)

Broadhurst, A V

2001-05-01

Hydroxylapatite (also called hydroxyapatite), a form of calcium phosphate, can be used as a matrix for the chromatography of both proteins and nucleic acids. Protocols are provided for both standard low-pressure chromatography of a protein mixture using a hydroxylapatite column prepared in the laboratory, and an HPLC method, applicable to proteins and nucleic acids, that uses a commercially available column. Alternate protocols describe column chromatography using a step gradient or batch binding and step-gradient elution.

Jenseits von "Identität"? : Zu den Un/Möglichkeiten nicht-identitärer Strategien politischen Handelns

OpenAIRE

Rostock, Petra

2014-01-01

Kulturalisierungen und Zuschreibungen ›kollektiver Identitäten‹ dienen in Debatten um die Einwande­rungsgesellschaft Deutschland immer wieder dazu eine soziale Ordnung zu konstruieren, die zwischen denen unterscheidet, die dazu gehören und jenen, die nicht dazu gehören. Gleichzeitig formiert sich ›Identitätspolitik‹ als eine widerständige politische Praxis. Sie greift im Bewusstsein einer gemeinsamen Geschichte der Ausbeutung und Unterdrückung infolge einer zugewiesenen und konstruierten ›Ide...

Ein Versuch, Naturverhältnisse aus feministischer Sicht zu interpretieren Another attempt to explain the natural environment from a feminist perspective

Directory of Open Access Journals (Sweden)

Helga Purgand

2002-07-01

Full Text Available Mit dem vorliegenden Sammelband Geschlechterverhältnisse – Naturverhältnisse wird nach dem innovativen Beitrag der feministischen Debatte für umweltsoziologisches Denken gefragt und nach Überschneidungen, Grenzen und Zwischenräumen zwischen „Geschlecht“ und „Natur“ gesucht. In ihm wird der lobenswerte Versuch unternommen, einen Zusammenhang zwischen Geschlechter- und Naturverhältnissen herzustellen „die in der Umweltsoziologie bislang stark vernachlässigte feministische Diskussion und Geschlechterforschung einzubeziehen und als genderbezogene Perspektive zu etablieren“. (S. 9 Das Buch enthält Beiträge von 15 Autorinnen, die unterschiedliche Natur- und Geschlechtsverhältnisse facettenreich, überwiegend kreativ und theoretisch anspruchsvoll betrachten. Das Buch enthält Zugänge aus der allgemeinen Soziologie, den Sprach- und Kulturwissenschaften, aus politik- und naturwissenschaftlichen Zusammenhängen. Den ausdrücklich formulierten Anspruch, von multi- zu einer inter-disziplinären Durchdringung zu gelangen, erfüllt es nur in Ansätzen (besonders mit der Einleitung und den theoretischen Problemexplikationen. Das zustande gekommene „Nach-, Zusammen- und Querdenken“ über Begriffe, Theorien und neuere Forschungsansätze (von Foucault über Butler bis zu Donna Haraway belegt die Notwendigkeit, die naturwissenschaftlichen Annahmen „immanent zu dekonstruieren“. Sehr aufschlussreich sind in diesem Zusammenhang die Beiträge von Irmgard Schultz, Elvira Scheich, aber auch von Mary Mellor und besonders von Paula-Irene Villa, die interessante und kreative Gedanken zur Klärung des Verhältnisses von Natur, Kultur und Geschlecht anbieten. Deutlich wurde, dass weiterhin ein kontroverses Ringen um angemessene konzeptionelle Fassungen von Geschlechts- und Naturverhältnissen und die Integration von Gender als zentraler analytischer Querschnitts-Kategorie nötig sind. Insgesamt ist dem Buch ist eine schnelle Verbreitung und

Quantenphysik und Kommunikationswissenschaft auf dem Weg zu einer allgemeinen Theorie der Kommunikation

CERN Document Server

Hamberger, Erich

2015-01-01

Der Quantenphysiker Herbert Pietschmann beschäftigt sich seit Jahrzehnten mit dem Phänomen Kommunikation. Der Kommunikationswissenschaftler Erich Hamberger setzt sich seit langem mit der Frage der Adaptierung erkenntnistheoretischer Einsichten der Quantentheorie für die Geistes- und Biowissenschaften auseinander. 2003 begegnen sich die beiden - und staunen über die „verschränkten Erkenntnisinteressen“. 2006 bestreiten sie eine erste gemeinsame universitäre Lehrveranstaltung. 2011 folgt Das Phänomen Kommunikation transdisziplinär betrachtet. Aus ihrer Zusammenarbeit ist dieses Buch entstanden. Naturwissenschaft arbeitet auf der Grundlage des mechanistischen Denkrahmens. Die bisher einzige Ausnahme ist die Quantenphysik. Weder Leben noch Kommunikation ist mittels des mechanistischen Denkrahmens zu verstehen. Auch der Denkrahmen der Quantenphysik reicht dazu nicht aus. Der Bedarf nach adäquatem Denken im Bereich der Kommunikation kann durch quantenphysikalisches Denken NICHT befriedigt werden, jedoc...

Euphemismen und Dysphemismen im Flexibilisierungsdiskurs. Auf dem Weg zu einem mehrperspektivischen Untersuchungsdesign

Directory of Open Access Journals (Sweden)

Goranka Rocco

2015-07-01

Full Text Available Abstract – This article outlines  theoretical and empirical prolegomena to the discourse-analytical study of euphemisms and dysphemisms which appear in the discourse of ‘flexibility’. After giving an operative definition of the euphemisms and dysphemisms and discussing some epistemological and other problems, the article presents an „EuDy-Modell“ called framework for studying euphemisms and dysphemisms from the perspective of discourse linguistics.Abstract – Der Beitrag enthält theoretische und empirische Prolegomena zu einer diskurslinguistisch orientierten Untersuchung von Euphemismen und Dysphemismen im Flexibilisierungsdiskurs. Zunächst werden eine funktionale Arbeitsdefinition der Begriffe Euphemismus und Dysphemismus gegeben und einige epistemologische und andere Probleme des Forschungsvorhabens erörtert, um im Anschluss ein Modell zur Analyse von Euphemismen und Dysphemismen aus der diskurslinguistischen Perspektive – das „EuDy-Modell“ – vorzustellen.

Nachtraege zu den „Tertiaerschichten auf Java.” 1ter Nachtrag: Mollusken. Nach Sammlungen der Indischen Bergbeamten, Hunghuhn’s und Reinwardt’s

NARCIS (Netherlands)

Martin, K.

1881-01-01

Durch Vermittelung Verbeek’s erhielt ich eine grosse Reihe von Versteinerungen, welche von Bergbeamten Indiens (hauptsächlich von R. Everwijn und P. van Dijk) gesammelt waren und sich bis vor Kurzem, ohne näher untersucht zu sein, in Batavia befanden ¹). Diese Sammlung umfasste neben vielem

Der grüne Weg zu Open Access: institutionelle und fachliche Repositorien / The Green Road to Open access: institutional and subject repositories

Directory of Open Access Journals (Sweden)

Bauer, Bruno

2009-06-01

Full Text Available The recent issue 1/2009 of GMS Medizin – Bibliothek – Information has a focus on „The green road to open Access: institutional and subject repositories“. Self-archiving and storing scholarly publications on a print server were also central topics in many presentations at the 9th International Bielefeld Conference in February 2009. The authors in this issue are Birgit Schmidt and Karin Ilg-Hartecke (Open Access in Deutschland – erweiterte Perspektiven für die Wissenschaft, Christoph Bruch and Anja Lengenfelder (Unterstützung des Grünen Weges zu Open Access an der Max-Planck-Gesellschaft, Ulrich Herb and Matthias Müller (Nuancen in Grün: Betrieb eines institutionellen und disziplinären Repositoriums – Erfahrungen und Entwicklungen an der Saarländischen Universitäts- und Landesbibliothek, Timo Borst and Jan B. Weiland (EconStor: ein fachliches Repositorium für die Wirtschaftswissenschaften, Antonella de Robbio and Michael Katzmayr (The management of an international open access repository: the case of E-LIS and Christian Gumpenberger (The EPrints story: Southampton as the cradle of institutional self-archiving.Furthermore this focus issue features an interview of a representative of a research funding organisation (Repositorien: Der grüne Weg zu Open Access Publishing aus der Perspektive einer Forschungsförderungsorganisation. 10 Fragen von Bruno Bauer an Falk Reckling, Mitarbeiter des FWF Der Wissenschaftsfonds and an interview of a publisher (Repositorien: Der grüne Weg zu Open Access Publishing aus der Perspektive der International Association of Scientific, Technical & Medical Publishers (STM: 10 Fragen von Bruno Bauer an Barbara Kalumenos, Director of Public Affairs bei STM.

Rezension zu: Mary Pepchinski: Feminist Space. Exhibitions and Discourses between Philadelphia and Berlin 1865–1912. Weimar: VDG Verlag und Datenbank für Geisteswissenschaften 2007.

Directory of Open Access Journals (Sweden)

Monika Kaiser

2009-10-01

Full Text Available Mary Pepchinski widmet ihre Untersuchung temporären Ausstellungen, die im Zeitraum von 1865 bis 1912 im deutschsprachigen Raum und in den USA entstanden sind und die zum Ziel hatten, in der bürgerlichen Öffentlichkeit Räume für feministische Anliegen und Diskussionen zu schaffen. In diesen um 1900 neu entstehenden Räumen der weiblichen Kultur spiegeln sich die feministischen Diskurse der Epoche und fließen in die von den Akteurinnen des gehobenen Bürgertums geschaffenen, charakteristischen Raumschöpfungen ein. Die Autorin stellt bislang unbekanntes Quellenmaterial vor und eröffnet durch ihren interdisziplinären Blick den Zugang zu einem vernachlässigten, da bislang unbekannten Teil der Kulturgeschichte der Moderne.

Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

Science.gov (United States)

Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

2017-09-01

A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation techniques: Chromatography

Science.gov (United States)

Coskun, Ozlem

2016-01-01

Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

Comprehensive two-dimensional liquid chromatography: Ion chromatography × reversed-phase liquid chromatography for separation of low-molar-mass organic acids

NARCIS (Netherlands)

Brudin, S.S.; Shellie, R.A.; Haddad, P.R.; Schoenmakers, P.J.

2010-01-01

In the work presented here a novel approach to comprehensive two-dimensional liquid chromatography is evaluated. Ion chromatography is chosen for the first-dimension separation and reversed-phase liquid chromatography is chosen for the second-dimension separation mode. The coupling of these modes is

„Weder dem Vergangenen anheimfallen noch dem Zukünftigen. Es kommt darauf an, ganz gegenwärtig zu sein“

Directory of Open Access Journals (Sweden)

Christian Filk

2012-03-01

Full Text Available Aufwachsen und Leben in der Wissensgesellschaft wird schon länger durch die Diskussion um ‚Informationsarme‘ und ‚Informationsreiche‘ begleitet. Jüngere wissenschaftliche Studien belegen das mangelnde oder gar nicht vorhandene Wissen zu wichtigen politischen, geschichtlichen und ethischen Themen wie Nationalsozialismus und Shoah. Christian Filk untersucht wesentliche Grundsätze moderner Geschichtsschreibung und den angemessenen Einsatz von Wissensmedien. Schliesslich erörtert er, wie elektronische, digitale und soziale Medien dazu beitragen können, mehr über den Genozid von etwa sechs Millionen europäischen Juden während des Zweitens Weltkriegs zu erfahren.For some time, growing up and living in a knowledge-based society is accompanied by the discussion on ‚information poor‘ and ‚information rich‘. Recent Scientific studies show the lack or non-existing knowledge on important political, historical and ethical issues such as Nazism and the Holocaust. Christian Filk examines essential principles of modern history and appropriate use of knowledge media. Finally he discusses, how electronic, digital and social media could help to learn more about the genocide of six million European Jews during World War II.

Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

Directory of Open Access Journals (Sweden)

Joris Meurs

2016-08-01

Full Text Available This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC, gas chromatography (GC and supercritical fluid chromatography (SFC. To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a plot will be shown in which the plate height is plotted against the linear flow velocity. Hence, this application will give optimized flow rates for any set conditions with minimal effort.

L’eau convoitée de la Guyane vénézuélienne1

Directory of Open Access Journals (Sweden)

Anne Pene-Annette

2004-12-01

Full Text Available La Guyane vénézuélienne, région dont la planification est contrôlée par l’Etat, joue un rôle majeur dans le développement économique du pays. Le potentiel hydrologique du fleuve Caroni est convoité pour les usages hydroélectriques, industriels et urbains qui se concentrent dans le pôle d’industrie lourde de Ciudad Guayana. La planification dirigiste, qui se reflète aussi dans la gestion du « pétrole bleu », est en concurrence avec la politique de décentralisation.

Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

International Nuclear Information System (INIS)

Castro, A.; Ibanez, J.; DiCesare, J.L.; Adams, R.F.; Malkus, H.

1978-01-01

Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

Überlegungen zu einer entrepreneur-orientierten Ausbildung an gewerblichen Fachschulen: eine Bestandsaufnahme mit Vorschlägen für eine Ergänzung des Curriculums

OpenAIRE

Hartmann, Falk

2010-01-01

In der Arbeit wird untersucht ob eine Ausbildung zum Entrepreneur, also zur Selbständigkeit möglich ist und es wird ein geeigneter curricularer Ansatz gesucht eine Entrepreneurship Education in die Ausbildung zum staatlich geprüften Techniker Maschinentechnik zu integriereren.

Metal-organic frameworks in chromatography.

Science.gov (United States)

Yusuf, Kareem; Aqel, Ahmad; ALOthman, Zeid

2014-06-27

Metal-organic frameworks (MOFs) emerged approximately two decades ago and are the youngest class of porous materials. Despite their short existence, MOFs are finding applications in a variety of fields because of their outstanding chemical and physical properties. This review article focuses on the applications of MOFs in chromatography, including high-performance liquid chromatography (HPLC), gas chromatography (GC), and other chromatographic techniques. The use of MOFs in chromatography has already had a significant impact; however, the utilisation of MOFs in chromatography is still less common than other applications, and the number of MOF materials explored in chromatography applications is limited. Copyright © 2014 Elsevier B.V. All rights reserved.

Report: Affinity Chromatography.

Science.gov (United States)

Walters, Rodney R.

1985-01-01

Supports, affinity ligands, immobilization, elution methods, and a number of applications are among the topics considered in this discussion of affinity chromatography. An outline of the basic principles of affinity chromatography is included. (JN)

Zu entwicklungstendenzen im satzbau der Deutschen sprache der gegenwart unter besonderer Berücksichtigung der ausrahmung

Directory of Open Access Journals (Sweden)

Jasna Makovec

1983-01-01

Full Text Available Die vorliegende Arbeit wurde durch das Bestreben motiviert, weitere Ergänzungen zum Phänornen "Ausrahrnung in der modernen deutschen Schriftsprache der Gegenwart" zu leisten. Der Ausgangspunkt dieses "fakultativ" geregelten Bereiches ist die Annahme bzw. die Arbeitshypothese, daß sich linguistische und außerlinguistische Faktoren einander zuordnen lassen. Das bedeutet, daß die Linearität innerhalb des Kornrnunikationspro­ zesses auch einige wichtige kommunikative Funktionen auszuüben hat, und daß die kontextuellen Modifikationen der Stellungsva­ rianten bei gleichern Denotatsbezug unter diesern Blickwinkel untersucht werden müssen, und nicht gleich als stilistische Varianten qualifiziert werden.

Chromatography of phosphorus oxoacids

International Nuclear Information System (INIS)

Ohashi, S.

1975-01-01

The present state of studies on the chromatographic separation of phosphorus oxoacids is surveyed. In this paper, chromatographic techniques are divided into four groups, i.e. paper and thin-layer chromatography, paper electrophoresis, ion-exchange chromatography, and gel chromatography. The separation mechanisms and characteristics for these chromatographic methods are discussed and some examples for the separation of phosphorus oxoacids are described. As examples of the application of ion-exchange and gel chromatography, studies on the hot atom chemistry of 32 P in solid inorganic phosphates and those on the substitution reactions between diphosphonate (diphosphite) and polyphosphates are reported. (author)

Column Liquid Chromatography.

Science.gov (United States)

Majors, Ronald E.; And Others

1984-01-01

Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

Immune chromatography: a quantitative radioimmunological assay

International Nuclear Information System (INIS)

Davis, J.W.; Demetriades, M.; Bowen, J.M.

1984-01-01

Immune chromatography, a radioimmunological binding assay, employs paper chromatography to separate immune complexes from free antigen and antibodies. During chromatography free antigen and antibodies become distributed throughout the paper, while immune complexes remain near the bottoms of the strips. The chromatographic differences can be made quantitative by using either iodinated antigens or antibodies. Under these conditions nanogram quantities of antigen can be detected or antibodies in sera diluted several 1000-fold. The immune chromatography assay can also be performed as an indirect assay, since the paper strips are cut from nitrocellulose paper. In this case the immune components are absorbed by the paper during chromatography. Antigen is then detected with an iodinated second antibody. The indirect immune chromatography assay is particularly useful for identifying different sera that react with the same antigen. Reaction with the first serum before chromatography reduces the amount of antigen available to the second serum following chromatography. In addition to characterizing the immune chromatography procedure, we discuss the possible applications of chromatography assays for the quantitation of other types of molecular binding interactions. (Auth.)

Development and prototypical application of analysis methods for complex anion mixtures in waters and heavy metal organyls in sediments; Entwicklung und prototypische Anwendung von Analysenverfahren fuer komplexe Anionengemische in Waessern und Schwermetallorganylen in Sedimenten. Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Anders, B.; Knoechel, A.; Potgeter, H.; Staub, S.; Stocker, M.

2002-07-01

When it comes to assessing the hazards emanating from heavy pollutants in waters mere elemental analysis provides too little information. Due to the great differences in toxicity and mobility it is important to know more about the exact species in question. This is particularly true of heavy metals that form stable organyls, specifically As, Pb, Sn and Hg, but also of alkylated arsenic acids, which need to be measured in complex anion mixtures. The purpose of the present project was to develop robust, powerful analysis methods and thus overcome the existing deficit in reliable analysis methods for these substances. An important approach in this connection is the use of coupled chromatography and detection systems for separation and analysis. [German] Hinsichtlich der von einer Schwermetallbelastung in Gewaessern ausgehenden Gefahren liefert die reine Elementanalytik nur unzureichende Aussagen. Aufgrund der grossen Unterschiede in Toxiditaet und Mobilitaet ist die Kenntnis der jeweils vorliegenden Spezies bedeutungsvoll. Dies gilt in besonderem Masse fuer die stabile Organyle bildenden Schwermetalle As, Pb, Sn und Hg sowie die alkylierten Arsensaeuren, die es innerhalb komplexer Anionengemische zu bestimmen gilt. Hinsichtlich ihrer sicheren Bestimmung bestehen methodische Defizite, die das vorliegende Projekt durch die Entwicklung robuster, nachweisstarker Analysenverfahren zu beseitigen versucht. Grosse Bedeutung kommt dabei gekoppelten Systemen aus Chromatographie und Detektion als Trenn- und Bestimmungsmethode zu. (orig.)

Die Digitale Bibliothek der Akademie der Wissenschaften zu Göttingen

Directory of Open Access Journals (Sweden)

Daniel Beucke

2014-12-01

Full Text Available Die Akademie der Wissenschaften zu Göttingen (AdWG und die niedersächsische Staats- und Universitätsbibliothek Göttingen (SUB haben ihre bestehende Kooperation zum Webportal der AdWG intensiviert, das einen Überblick über die Aktivitäten der Göttinger Akademie und umfangreiche Information zu den zahlreichen Langzeitvorhaben bietet und die digitalen Publikationen präsentiert. Zentraler Bestandteil des Webportals ist die Digitale Bibliothek der AdWG, für die im Rahmen der Kooperation neue Präsentationsformen für die Forschungsdaten aus den Akademie-Vorhaben konzipiert und entwickelt wurden. Ein Beispiel für die Umsetzung neuer Präsentationsformen im Portal ist das Edfu-Projekt, dessen Ziel eine Gesamtübersetzung aller Inschriften des Tempels von Edfu in Oberägypten ist. Hinzugezogen werden dazu alle internen, greifbaren, in den Schriften enthaltenen Parallelen, auf die online über das Webportal zugegriffen werden kann. Zerstörte Bereiche lassen sich dadurch oftmals ebenso ergänzen, wie zunächst unverständliche Textpassagen mit Sinn versehen werden können. Nicht nur die bereits vorübersetzten Texte sind auf diese Weise abrufbar, sondern darüber hinaus zahlreiche zusätzliche Materialien, wie z.B. das Fotoarchiv mit seinen mehr als 20.000 Bildern. Die Vernetzung all dieser Daten schafft einen für die Wissenschaft ungewöhnlich tiefen Einblick in die Planung und Konzeption eines altägyptischen Tempels, seiner religiösen Hintergründe und historischen Zusammenhänge. The Göttingen Academy of Sciences and Humanities (AdWG and the Göttingen State and University Library (SUB have intensified their existing cooperation on the web portal of the AdWG. The portal provides an overview of the activities of the Göttingen Academy as well as extensive information on its numerous long-term projects. It also presents the academy’s digital publications. A crucial part of the web portal is the Digital Library of the AdWG. Within the

Analytic studies of test problems of laser welds in consideration of tolerated hardness peaks. Final report; Analytische Untersuchungen der Pruefproblematik an laserstrahlgeschweissten Verbindungen unter besonderer Beruecksichtigung der zu tolerierenden Haertespitzen. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

Test methods for laser welds were investigated under the following aspects: 1. Setting a defined cracking path by changing the test piece geometry - is it possible and does it make sense? 2. Can the results obtained with changed test piece geometries be applied to standard test pieces? 3. Is crack displacement typical of small test pieces, or is it observable in real components as well? 4. Should the cracking path be predefined at all if it results in 'non-realistic' fractures? The focus was on notched bar impact tests. [German] Ziel des Forschungsvorhabens war die Ermittlung geeigneter Pruefverfahren zur Charakterisierung einer Laserstrahlschweissnaht. Folgende Fragen sollten geklaert werden: 1. Ist es moeglich und sinnvoll, mit einer Aenderung der Probengeometrie (z.B. Einbringen von Seitenkerben) den Rissverlauf in das aufgehaertete Laserschweissgut zu zwingen? 2. Welche Aussagen liefern uns die Ergebnisse dieser abgeaenderten Probengeometrie und inwiefern sind diese vor allen Dingen beim Kerbschlagbiegeversuch auf die Ergebnisse der standardisierten Probengeometrie zu uebertragen? 3. Ist das Rissauswandern ein nur fuer Kleinproben typisches Verhalten oder wird es auch bei realen Bauteilen beobachtet? 4. Ist es sinnvoll, den Rissverlauf in die sproede, aufgehaertete Schweissnaht zu zwingen, obwohl daraus ein 'realitaetsfernes' Bruchverhalten resultiert? Dabei wurde der Schwerpunkt auf die Untersuchung des Kerbschlagbiegeversuches gelegt. (orig.)

Der kleine Unterschied. Zu den Selbstverhältnissen von Verantwortung und Pflicht

Directory of Open Access Journals (Sweden)

Vogelmann Frieder

2015-12-01

Full Text Available Die Debatte um die Differenz von „Verantwortung“ und „Pflicht“ ist kein bloßer Streit um Wörter, geht es doch um Begriffe, für die der Anspruch erhoben wird, sie seien konstitutiv für moralische Normativität oder gar für Normativität per se. Doch welchen Unterschied macht es, die besondere Bindungskraft von Normativität über Verantwortung oder über Pflicht zu explizieren? Die Genealogie der philosophischen Reflexionen auf Verantwortung lokalisiert die Differenz zwischen Pflicht und Verantwortung in den jeweiligen Selbstverhältnissen, die mit diesen Begriffen verbunden werden. Die Analyse der Struktur dieser Selbstverhältnisse erklärt sowohl, warum Verantwortung häufig als moderner Ersatzbegriff für Pflicht gedacht wird, als auch, welchen Unterschied die Explikation der Bindungskraft von Normativität über Verantwortung oder Pflicht macht: Je nachdem, mit welchem Begriff normative Kraft erläutert wird, wandert das entsprechende Selbstverhältnis in die Verfasstheit von Normativität ein.

Enantioseparations in counter-current chromatography and centrifugal partition chromatography.

Science.gov (United States)

Foucault, A P

2001-01-12

Examples of chiral separations in counter-current chromatography (CCC) and centrifugal partition chromatography (CPC) are not numerous, due to the difficulty of finding chiral selectors highly selective in the liquid phase as well as a combination of solvents that does not destroy the selectivity and retains the capacity to elute chiral isomers of interest. New ideas and new chiral selectors generally come from other separation techniques, as will be highlighted in this review.

Thin-layer and paper chromatography

International Nuclear Information System (INIS)

Sherma, J.

1986-01-01

This selective review covers the literature of thin-layer chromatography (TLC) and paper chromatography (PC) cited in Chemical Abstracts from December 5, 1983, through November 25, 1985, and Analytical Abstracts from November 1983 to November 1985. Also researched directly were the following important journals publishing papers on TLC and PC: the Journal of Chromatography (including its bibliography issues), Journal of High Resolution Chromatography and Chromatography Communications, Journal of Chromatographic Science, Chromatographia, Analytical Chemistry, JAOAC, and the special TLC issues of the Journal of Liquid Chromatography. Many of the inherent advantages of TLC that are obvious to workers familiar with high performance, quantitative theory and practice still are not appreciated adequately by the majority of people using chromatography. These include unrestricted access to the separation process; introducing magnetic, thermal, electrical, and other physical forces to improve resolution; high sample throughput; truly multidimensional separations; and the use of controlled multiple gradients. Many advantages of TLC relative to column chromatography were discussed in the Introductions to our 1982 and 1984 reviews of TLC in this Journal. No complete commercial robotics system specifically for TLC has been developed, but all necessary modules are available for such a system. The combination of robotics, with the continued development of theory, practice, and instrumentation will lead eventually to TLC systems that are unrivaled for speed, versatility, accuracy, precision, and sensitivity. 573 references

Calcium-sensitive immunoaffinity chromatography

DEFF Research Database (Denmark)

Henriksen, Maiken L; Lindhardt Madsen, Kirstine; Skjoedt, Karsten

2014-01-01

Immunoaffinity chromatography is a powerful fractionation technique that has become indispensable for protein purification and characterization. However, it is difficult to retrieve bound proteins without using harsh or denaturing elution conditions, and the purification of scarce antigens...... to homogeneity may be impossible due to contamination with abundant antigens. In this study, we purified the scarce, complement-associated plasma protein complex, collectin LK (CL-LK, complex of collectin liver 1 and kidney 1), by immunoaffinity chromatography using a calcium-sensitive anti-collectin-kidney-1 m...... chromatography was superior to the traditional immunoaffinity chromatographies and resulted in a nine-fold improvement of the purification factor. The technique is applicable for the purification of proteins in complex mixtures by single-step fractionation without the denaturation of eluted antigens...

[Dennis Hormuth. Livonia est omnis divisa in partes tres : Studien zu mental mapping der livländischen Chronistik in der Frühen Neuzeit (1558-1710) ] / Stefan Donecker

Index Scriptorium Estoniae

Donecker, Stefan, 1977-

2014-01-01

Arvustus: Hormuth, Dennis. Livonia est omnis divisa in partes tre : Studien zu mental mapping der livländischen Chronistik in der Frühen Neuzeit (1558-1710). (Quellen und Studien zur Geschichte des östlichen Europa, 79). Stuttgard, 2012

[Staat und Orden. Das Verhältnis des Deutschen Ordens zu den Städten in Livland, Preußen und im Deutschen Reich] / Bernhart Jähnig

Index Scriptorium Estoniae

Jähnig, Bernhart, 1941-

1995-01-01

Arvustus: Staat und Orden. Das Verhältnis des Deutschen Ordens zu den Städten in Livland, Preußen und im Deutschen Reich, hg. v. Udo Arnold. (Quellln und Studien zur Geschichte des Deutschen Ordens. 4.) Marburg: N. G. Elwert Verlag 1993

Simultaneous analysis for water- and fat-soluble vitamins by a novel single chromatography technique unifying supercritical fluid chromatography and liquid chromatography.

Science.gov (United States)

Taguchi, Kaori; Fukusaki, Eiichiro; Bamba, Takeshi

2014-10-03

Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a "unified" chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of -2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system. Copyright © 2014. Published by Elsevier B.V.

Zu einigen mittelalterlichen Amtsbezeichungen in der Toponymie Serbiens

Directory of Open Access Journals (Sweden)

Aleksandar Loma

2015-12-01

Full Text Available Die vorliegende Arbeit behandelt den Ortsnamen Šepšin, wie ein Dorf in Serbien unweit von Mladenovac, südlich von Belgrad, heißt. Nach dem Zeugnis der türkischen Verzeichnisse des 16. Jh.s, hat sich die heutige Form des Namens über Šemšin aus Šemčin entwickelt, wie sein Erstbeleg aus 1528 lautet. Vorausgesetzt, dass sich das anlautende Š- aus S- durch Assimilation vom Typ šiče < siče ‘zischt’ entwickelt hat, lässt sich die ursprügliche Namenform als *Sěmčijin wiederherstellen, wo sich um ein Possessivadjektiv zur altserbischen Amtsbezeichnung sěmьčija handelt. Nur als Hapax in der BanjskaUrkunde aus 1316. belegt, wird sie mit aksl. samъčii ‘praefectus’ gleichgesetzt, wo wahrscheinlich ein Lehnwort aus dem Protobulgarischen vorliegt. In diesem Fall liesse sich das ě der altserbischen Nebenform durch den Einfluss des urslav. Wortes *sěmь ‘Familie’ erklären. Anknüpfend wird die Frage nach der Herkunft eines anderen Ortsnamens aus demselben Gebiet, Hrčin, heute Vrčin, wieder in Betracht gezogen. Bisher unterschiedlich gedeutet, lässt sich er analogisch zu *Sěmčijin auf *Hrtčijin als Possessivbildung zur sonst unbelegten Hofamtsbezeichnung *xъrtьčii ‘für Windhunde (*xъrtъ zuständig, Hofjägermeister’ zurückführen. In beiden Fällen dürfte sich das maskuline Possessivadjektiv auf -in ursprünglich auf potok ‘Bach’ oder dol ‘Tal’ im Lehensbesitz der betreffenden Person bezogen haben.

Erhöht ein Opfer-Täter-Zyklus das Risiko, Sexualstraftaten als pädosexuelle Straftaten zu begehen? : Ergebnisse einer ereignisanalytischen Pilotstudie

OpenAIRE

Urban, Dieter; Lindhorst, Heiko

2004-01-01

Die Pilotstudie untersucht mittels multivariater Ereignisanalysen den Übergang vom ehemaligen Opfer pädosexuellen bzw. körperlichen Missbrauchs zum pädosexuellen Täter im Lebensverlauf verurteilter Sexualstraftäter. Zur Erklärung dieses Übergangs werden aus den wichtigsten täterorientierten Theoriemodellen drei Hypothesen abgeleitet, die empirisch getestet werden sollen. Diese Hypothesen betreffen das Risiko, nach Opfererfahrungen in der Kindheit zum Täter pädosexuellen Missbrauchs zu werden....

Erhöht ein Opfer-Täter-Zyklus das Risiko, Sexualstraftaten als pädosexuelle Straftaten zu begehen? : Ergebnisse einer ereignisanalytischen Pilotstudie

OpenAIRE

Urban, Dieter; Lindhorst, Heiko

2004-01-01

"Die Pilotstudie untersucht mittels multivariater Ereignisanalysen den Übergang vom ehemaligen Opfer pädosexuellen bzw. körperlichen Missbrauchs zum pädosexuellen Täter im Lebensverlauf verurteilter Sexualstraftäter. Zur Erklärung dieses Übergangs werden aus den wichtigsten täterorientierten Theoriemodellen drei Hypothesen abgeleitet, die empirisch getestet werden sollen. Diese Hypothesen betreffen das Risiko, nach Opfererfahrungen in der Kindheit zum Täter pädosexuellen Missbrauchs zu werden...

Rezension zu: Nicole C. Karafyllis, Gotling Ulshöfer: Sexualized Brains. Cambridge u.a.: MIT Press 2008

Directory of Open Access Journals (Sweden)

Sigrid Schmitz

2009-07-01

Full Text Available In der Auseinandersetzung um geschlechtliche Normierungen spielt die moderne Hirnforschung eine wirkmächtige und inzwischen disziplinenübergreifende Rolle. Nicole Karafyllis und Gotlind Ulshöfer stellen in diesem Sammelband mit Beiträgen aus Neurowissenschaft, Psychologie, Soziologie, Kulturwissenschaft und Philosophie ein multiperspektivisches Diskursfeld zu der Frage vor, ob die Emotionale Intelligenz (EI als erstrebenswerte Fähigkeit die klassische Kodierung in männliche Rationalität bzw. weibliche Emotionalität dekonstruieren und ein emanzipatorisches Potential entgegen gesellschaftlichen Hierarchisierungen entfalten kann. Viele Aspekte, Verbindungen zwischen den Diskurssträngen und wechselseitige Beeinflussungen, aber auch disziplinäre Eingrenzungen werden sichtbar, die eine kritische Fortführung des hier angestoßenen Dialogs notwendig machen.

Benefit analysis of e-business solutions for utilities; Nutzenbetrachtung von E-Business-Branchenloesungen. Der Online-Weg zu den Privatkunden

Energy Technology Data Exchange (ETDEWEB)

Koch, M.; Baier, D. [Lehrstuhl fuer Marketing und Innovationsmanagement und BTU Cottbus (Germany)

2003-04-07

E-Business-applications for internal and external business processes are an often dealt subject. In opposition to that the implementation of E-Business-Systems at the interface to the many private customers are taken only few notice. Even though the implementation requires additional investments utilities could save considerable costs. (orig.) [German] Die Unterstuetzung der internen und externen Geschaeftsprozesse durch E-Business-Systeme ist eine aufgrund ihrer Bedeutung oft behandelte Thematik. Weitgehend unbeachtet blieb bisher der Einsatz von E-Business-Systemen an der Schnittstelle zu den vielen Privatkunden. Trotz zusaetzlich notwendiger Investitionen lassen sich gerade an dieser Stelle hohe Kosten sparen. (orig.)

Liquid Chromatography in 1982.

Science.gov (United States)

Freeman, David H.

1982-01-01

Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

Review of preliminary results of the project `Co-cracking of plastics and petroleum residues`; Uebersicht zu den ersten Ergebnissen des Projektes Cocracking von Kunststoffen und Erdoelrueckstand

Energy Technology Data Exchange (ETDEWEB)

Uhmann, R; Koepsel, R F; Kuchling, T; Simanjenkov, V [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Energieverfahrenstechnik und Chemieingenieurwesen

1998-09-01

Coprocessing of petroleum residues and plastics is a promising technology, although some problems concerning waste plastics must be clarified prior to its implementation. In general, it can be stated that with a careful choice of operating parameter combinations, oil yields will be higher than for thermal treatment of petroleum residues alone (e.g. a 35% yield increase is achieved by adding 25% of plastics, which is a disproportionately high increase). Waste plastics thus become a valuable material for processing. (orig.) [Deutsch] Das untersuchte Coprocessing von VR und Kunststoffen ist ein erfolgversprechender Weg der Kunststoffverwertung und des tiefen Crackens von Erdoelrueckstand. Die Klaerung der mit Altkunststoffen verbundenen Fragen bedarf weiterer Untersuchungen. Allgemein kann festgestellt werden, dass bei entsprechenden Parameterkombinationen bessere Oelausbeuten erzielt werden als bei der thermischen Behandlung von reinem VR. Ein Beispiel dafuer ist in der Abbildung 10 dargestellt. Durch eine 25%-ige Erhoehung der Einsatzstoffmasse durch Kunststoffzugabe wird eine im Vergleich zu reinem VR um ca. 36% hoehere Oelausbeute erzielt, was einer ueberproportionalen Erhoehung entspricht. Altkunststoff wird bei diesem Prozess unter Nutzung des Wasserstoff-potentials von Polymeren zu einem wertvollen Einsatzstoff. (orig.)

E-Portfolios, ‹eine Möglichkeit, viel für sich selbst zu lernen›. Der Einsatz von E-Portfolios als Reflexionsinstrument am Beispiel der Viadrina PeerTutoring-Ausbildung

Directory of Open Access Journals (Sweden)

Stefanie Vogler-Lipp

2017-03-01

Full Text Available Das Reflektieren und Verstehen des eigenen Lernprozesses gehört zu den studienrelevanten Fertigkeiten, die erlernt und während eines erfolgreichen Studiums vertieft werden sollten. Seit 2012 wird im Rahmen der Viadrina PeerTutoring-Ausbildung an der Europa-Universität Viadrina auf den Ausbau und die Weiterentwicklung der Reflexionskompetenzen sehr viel Wert gelegt. Im Folgenden werden die theoretischen Grundlagen zusammengefasst und erläutert, wie gutes Reflektieren angeleitet wird. Die Studierenden reflektieren ihre Lernprozesse in E-Portfolios. Um das komplexe Zusammenspiel einer guten Anleitung zum Reflektieren, den tatsächlichen Ergebnissen in den E-Portfolios und den Eindrücken der Mitarbeiter/innen am Zentrum für Schlüsselkompetenzen und Forschendes Lernen nachvollziehen zu können, werden am Ende einzelne Auszüge aus den E-Portfolios vorgestellt und für den Einsatz von E-Portfolio als Reflexionsinstrument plädiert.

Mehr Last als Lust – Ein weiterer Sammelband zu „(Frauen-Körper“ More Encumbrance than Enjoyment

Directory of Open Access Journals (Sweden)

Paula-Irene Villa

2006-11-01

Full Text Available Dieser Band vereint acht heterogene Aufsätze zu „Lust und Last am eigenen Körper“ von Frauen. Alle Beiträge gehören zum Spektrum psychologischer Reflexion; die Themen reichen dabei von Sport über Kochen und Essen bis Schönheit, die Zugänge von Psychoanalyse über experimentelle Psychologie bis hin zu freier Assoziation auf der Grundlage klinisch-praktischer Arbeit. Ein roter Faden durch die Beiträge ist nicht erkennbar und so wirkt die Vielfalt beliebig. So unterschiedlich die Beiträge sind, so unterschiedlich ist auch ihre Qualität. Leider kommen einige Artikel über die unkritische Zusammenstellung anderer Arbeiten nicht hinaus, die meisten nehmen kaum Bezug auf das inzwischen breite und institutionalisierte Feld der (sozial- und kulturwissenschaftlichen Körperforschung. Doch haben manche Aufsätze interessante empirische Einblicke zu bieten, die zur weiteren Reflexion anregen, und einige wenige Beiträge sind so differenziert, dass sich mit ihnen weiterdenken und -forschen lässt. Insgesamt bereitet die Lektüre des Buches weder ‚Einsteiger/-innen‘ noch ‚Fortgeschrittenen‘ der wissenschaftlichen Beschäftigung mit (Frauen-Körpern Lust, sondern erweist sich – bis auf Ausnahmen, die allerdings auch in ausführlicherer Form anderenorts publiziert wurden – eher als Last. Ärgerlich und alles andere als argumentativ überzeugend ist darüber hinaus das in manchen Texten enthaltene, mehr oder minder explizit artikulierte, ‚Feminismus- bzw. Frauenforschungs-Bashing‘.This volume joins together eight heterogeneous essays by women under the theme “enjoyment and encumbrance of the body.” All of the contributions belong within the spectrum of psychological reflection; the themes range from sports, cooking and eating, and beauty, to the process of psychoanalysis, experimental psychology, and free-association based on clinical practice. The thread throughout the contributions remains indiscernible and thus the

Der Einfluss des Country-of-Origin Effekts im Vergleich zu anderen Faktoren auf die Kaufabsicht und Markenpräferenz in der Produktgruppe PKW

OpenAIRE

Gerhold, Christine

2009-01-01

Der Konsument sieht sich im zunehmenden Maße mit einer großen Produktvielfalt, einer allgemeinen Homogenisierung der Produkte und einer ständigen Informationsüberflutung konfrontiert. Zur leichteren Orientierung werden aus dem großen Bündel an Produktinformationen, einzelne "Schlüsselinformationen", verstärkt zur Kaufentscheidung herangezogen. In der vorliegenden Arbeit wird untersucht, welche Bedeutung die Schlüsselinformation "Country-of-Origin" im Vergleich zu anderen Faktoren, wie Marke o...

Thermodesorbable passive collectors and thermodesorption injector for assessing the exposure of room occupants to organic pollutants - TOPAS; Thermodesorbierbare Passivsammler und zugehoeriger Thermodesorptionsinjektor fuer die Bestimmung der personenbezogenen Belastung mit organischen Luftschadstoffen - TOPAS

Energy Technology Data Exchange (ETDEWEB)

Cammann, K

1999-07-01

A sampling system for identification and quantification of room occupant exposure to organic airborne pollutants was to be developed. This comprised the development of a new sampling system involving high-resolution gas chromatography. [German] Im Rahmen des geplanten Forschungsprojektes sollte ein neuartiges, leistungsstarkes und dennoch kostenguenstiges Probennahmesystem zur Identifizierung und mengenmaessigen Erfassung der personenbezogenen Belastung mit organischen Luftschadstoffen entwickelt werden. Mit diesem System sollte es moeglich sein, die individuelle Einwirkung von Luftverschmutzungen mit organischen Schadstoffen auf weite Bevoelkerungsgruppen zu ermitteln. Erreicht werden sollte dieses Ziel durch eine neugestaltete Kombination der Passivsammlung als aeusserst einfach zu handhabendes Probennahmesystem in der Luftanalytik mit der Thermodesorption als nachweisstarkes Probenaufgabesystem fuer die hochaufloesende Gaschromatographie. (orig.)

Application of gas chromatography in hydrogen isotope separation

International Nuclear Information System (INIS)

Ye Xiaoqiu; Sang Ge; Peng Lixia; Xue Yan; Cao Wei

2008-01-01

The principle of gas chromatographic separation of hydrogen isotopes was briefly introduced. The main technology and their development of separating hydrogen isotopes, including elution chromatography, hydrogen-displacement chromatography, self-displacement chromatography and frontal chromatography were discussed in detail. The prospect of hydrogen isotope separation by gas chromatography was presented. (authors)

Dohmen, Dieter, Erbes, Annegret, Fuchs, Kathrin & Günzel, Juliane (2008). Was wissen wir über Nachhilfe? Sachstand und Auswertung der Forschungsliteratur zu Angebot, Nachfrage und Wirkungen. Bielefeld: Bertelsmann, 150 S. [Rezension

OpenAIRE

Mayr, Thomas

2014-01-01

Rezension von Dohmen, Dieter, Erbes, Annegret, Fuchs, Kathrin & Günzel, Juliane (2008). Was wissen wir über Nachhilfe? Sachstand und Auswertung der Forschungsliteratur zu Angebot, Nachfrage und Wirkungen. Bielefeld: Bertelsmann, 150 S. 29,90 EUR, ISBN 978-3763936656

Determination of radiochemical purity using gas chromatography

International Nuclear Information System (INIS)

1975-01-01

The concepts of chromatography, gas chromatography, activity, radiochemical impurity are defined; the procedure of the application of gas chromatography for detecting radiochemical purity of substances is standardized. (E.F.)

Fluchen und Flamen, um ein Mann zu sein? Die Verknüpfung von Geschlecht und Sprache durch Vorurteile

Directory of Open Access Journals (Sweden)

Nicola Döring

2001-11-01

Full Text Available Die hier besprochene Monographie der Linguistin Anja Gottburgsen beschäftigt sich theoretisch und empirisch mit sprachbezogenen Geschlechterstereotypen, also mit unseren Vorstellungen darüber, ob und wie Männer und Frauen jeweils in spezifischer und distinkter Weise sprachlich kommunizieren. Im Theorieteil der Arbeit wird der aktuelle Stand der soziolinguistischen und sozialpsychologischen Diskussion zu Geschlecht, Sprachverhalten und Stereotypisierung kritisch referiert und die Bedeutung von sprachbezogenen Geschlechterstereotypen erläutert. Im empirischen Teil berichtet die Autorin die Ergebnisse von drei Fragebogen-Studien mit deutschsprachigen Studierenden. Es zeigt sich, dass bei Studierenden unabhängig von Geschlecht und Geschlechtsrollenorientierung stereotype Vorstellungen über das sprachliche Verhalten von Männern und Frauen verbreitet sind.

Reimbursement for electricity supplied to the grid and the phaseout of franchise agreements. A critical review of recent developments of the law; Einspeiseverguetung und Auslaufen der Konzessionsvertraege - eine kritische Studie zu neueren Rechtsentwicklungen

Energy Technology Data Exchange (ETDEWEB)

Jackel, G. [Energieversorgung Schwaben AG, Stuttgart (Germany)

1994-12-31

Allowing more competition in all sectors of the economy is an acceptable strategy if resulting in social benefits, i.e. if profits are passed on to the citizens and consumers. If, however, such a liberalisation or deregulation ends up in a concentration of power by commercial enterprises to the disadvantage of consumers who have to pay higher electricity rates, or jeopardizes the reliability of power supply, such actionism on the part of the legislature may well adversely affect public welfare. This applies likewise to minor regulation, as is the Act on Compulsory Acceptance of Electricity From Renewable Energy Sources,(SEG), which puts an unproportionate load on the shoulders of the public utilities in order to satisfy interests of environmental policy. The paper explains these statements by examining effects expected to result from the SEG, and by referring to problems involved in the phaseout of franchise agreements. (orig./HSCH) [Deutsch] Die Einfuehrung von mehr Wettbewerb in allen Bereichen der Wirtschaft ist zu begruessen, wenn sich volkswirtschaftlich positive Entwicklungen einstellen, d.h. der Buerger, der Kunde davon profitiert. Wenn liberalisierende Eingriffe letztlich aber zu hoeheren Strompreisen oder zu geringerer Versorgungssicherheit fuehren, bei gleichzeitigem Konzentrationsschub in der Unternehmensstruktur, dann kann das Gemeinwohl durch gesetzgeberischen Aktionismus leicht Schaden nehmen. Dies gilt auch fuer Regulierungen minderer Art wie beim Stromeinspeisungsgesetzt (SEG), das die deutschen Energieversorgungsunternehmen (EVU) aus umweltpolitischen Erwaegungen weiter einseitig belastet. (orig./HSCH)

Operating experience for a closed-circuit interconnected system for flue gas desulphurization at Klingenberg heating power station; Betriebserfahrungen zu einem Kreislaufverbundsystem fuer die Rauchgasentschwefelung im Heizkraftwerk Klingenberg

Energy Technology Data Exchange (ETDEWEB)

Hultsch, T [Berliner Kraft- und Licht (BEWAG)-AG, Heizkraftwerk Klingenberg, Berlin (Germany); Mueller, U [BDAG Balcke-Duerr AG, Ratingen (Germany)

1995-05-01

The cleaning of flue gases imposes extreme demands on the material concerned. By keeping below the acid dewpoint, this leads to condensation of acid products on the heating surfaces. The correct selection of the appropriate material is decisive for the availability of the overall plant. In the case of the application described in this paper, it has been possible to show that nickel-based alloys are outstandingly suitable for withstanding those kinds of stresses over many years. However, independently of this, it is valid to test material selection for each individual case of application. (orig.) [Deutsch] Die Reinigung von Rauchgasen stellt extreme Anforderungen an den jeweiligen Werkstoff. Durch die Unterschreitung des Saeuretaupunktes kommt es dabei zu einer Kondensation der Saeureprodukte auf den Heizflaechen. Die Auswahl des geeigneten Materials ist entscheidend fuer die Verfuegbarkeit der Gesamtanlage. In dem hier dargestellten Anwendungsfall konnte gezeigt werden, dass Nickelbasis-Legierungen hervorragend geeignet sind, einer derartigen Beanspruchung ueber Jahre hinaus standzuhalten. Unabhaengig hiervon gilt es jedoch, fuer die Materialauswahl jeden Anwendungsfall einzeln zu pruefen. (orig.)

Brief Study and Spanish Translation of Die Kunst das Clavier zu Spielen by Friedrich Wilhelm Marpurg (Berlin, Henning, 1750

Directory of Open Access Journals (Sweden)

María de las Nieves Pascual León

2017-01-01

Full Text Available This paper includes the fi rst Spanish version of F. W. Marpurg’s treaty Die Kunst das Clavier zu spielen, which had been restricted for the common Spanish-speaking reader since its fi rst appearance in 1750. This philological translation of the treaty (with the facsimile of the fi rst edition and its Spanish translation on the opposite page is instroduced by a brief study of the text’s various editions published during the author’s life, and pretends to offer an initial approach to the treaty, to facilitate the public’s access to the work and to contribute to its full disclosure.

The weight of flash chromatography: A tool to predict its mass intensity from thin-layer chromatography

Directory of Open Access Journals (Sweden)

Freddy Pessel

2016-11-01

Full Text Available Purification by flash chromatography strongly impacts the greenness of a process. Unfortunately, due to the lack of the relevant literature data, very often this impact cannot be assessed thus preventing the comparison of the environmental factors affecting the syntheses. We developed a simple mathematical approach to evaluate the minimum mass intensity of flash chromatography from the retention factor values determined by thin-layer chromatography.

Supercritical fluid chromatography

Science.gov (United States)

Vigdergauz, M. S.; Lobachev, A. L.; Lobacheva, I. V.; Platonov, I. A.

1992-03-01

The characteristic features of supercritical fluid chromatography (SCFC) are examined and there is a brief historical note concerning the development of the method. Information concerning the use of supercritical fluid chromatography in the analysis of objects of different nature is presented in the form of a table. The roles of the mobile and stationary phases in the separation process and the characteristic features of the apparatus and of the use of the method in physicochemical research are discussed. The bibliography includes 364 references.

Comprehensive two-dimensional liquid chromatography and hyphenated liquid chromatography to study the degradation of poly(bisphenol A)carbonate

NARCIS (Netherlands)

Coulier, L.; Kaal, E.R.; Hankemeier, T.

2005-01-01

Size exclusion chromatography (SEC), gradient polymer elution chromatography (GPEC) and liquid chromatography at critical conditions (LC-CC) have been developed and applied to observe chemical changes in poly(bisphenol A)carbonate (PC) due to hydrolytic degradation. Especially LC-CC appeared to be

Characterisation of uremic "Middle molecular"fractions by gas chromatography mass spectrometry, isotachophoresis, and liquid chromatography

NARCIS (Netherlands)

Schoots, A.C.; Mikkers, F.E.P.; Claessens, H.A.; Smet, de R.; Landschoot, van N.; Ringoir, S.M.G.

1982-01-01

Uremic ultrafiltrates (and normal serum, for comparison) were fractionated by means of gel filtration. The collected fractions were further investigated by combined analytical techniques: "high- performance" liquid chromatography, gas chromatography, mass spectrometry, and isotachophoresis.

Thin-Layer and Paper Chromatography.

Science.gov (United States)

Sherma, Joseph; Fried, Bernard

1984-01-01

Reviews literature on chromatography examining: books, reviews, student experiments; chromatographic systems, techniques, apparatus; detecting and identification of separated zones; preparative chromatography and radiochromatography; and applications related to specific materials (such as acids, alcohols, amino acids, antibiotics, enzymes, dyes,…

Capillary gas-solid chromatography

International Nuclear Information System (INIS)

Berezkin, V.G.

1996-01-01

Modern state of gas adsorption chromatography in open capillary columns has been analyzed. The history of the method development and its role in gas chromatography, ways to construct open adsorptional capillary columns, foundations of the theory of retention and washing of chromatographic regions in gas adsorption capillary columns have been considered. The fields is extensively and for analyzing volatile compounds of different isotopic composition, inorganic and organic gases, volatile organic polar compounds, aqueous solutions of organic compounds. Separation of nuclear-spin isomers and isotopes of hydrogen is the first illustrative example of practical application of the adsorption capillary chromatography. It is shown that duration of protium and deuterium nuclear isomers may be reduced if the column temperature is brought to 47 K

Präferenzen, Wohlergehen und Rationalität – Zu den begrifflichen Grundlagen des libertären Paternalismus und ihren Konsequenzen für seine Legitimierbarkeit

Directory of Open Access Journals (Sweden)

Klonschinski Andrea

2016-07-01

Full Text Available Der libertäre Paternalismus (LP genießt in Politik, Wissenschaft und Öffentlichkeit eine große Popularität, die er insbesondere zwei Merkmalen verdankt: Erstens stützt sich der LP auf verhaltensökonomische Ergebnisse, die zeigen, dass individuelle Entscheidungen oft nicht der neoklassischen Rationalitätskonzeption entsprechen, sodass Individuen durch sogenanntes Nudging zu besseren, ihren wahren Präferenzen entsprechenden Entscheidungen verholfen werden könne. Zweites ist damit der Anspruch verbunden, das Wohlergehen der Individuen, wie sie selbst es verstehen, zu erhöhen. Dieser Beitrag zeigt anhand einer dogmengeschichtlichen Analyse der zentralen, dem LP zugrunde liegenden Begriffe Präferenz, Nutzen, Rationalität und Wohlergehen, dass der LP diesen Anspruch nicht einlösen kann. Eine detaillierte begriffliche Analyse ist deshalb geboten, weil diese Konzepte in der Ökonomik immer wieder für Missverständnisse sorgen. Eine theoriegeschichtlich informierte Untersuchung wiederum ist notwendig, da diese Konfusion insbesondere auf der Tatsache beruht, dass der Gehalt dieser Begriffe sich im Laufe der Zeit gravierend verändert hat und sich die verschiedenen Bedeutungen heute z. T. wechselseitig überlagern.

[Stadt und Orden. Das Verhältnis des deutschen Ordens zu den Städten in Livland, Preußen und im Deutschen Reich] / Bernhart Jähnig

Index Scriptorium Estoniae

Jähnig, Bernhart, 1941-

1995-01-01

Arvustus: Stadt und Orden. Das Verhältnis des deutschen Ordens zu den Städten in Livland, Preußen und im Deutschen Reich, hg. v. Udo Arnold. [Quellen und Studien zur Geschichte des Deutschen Ordens. 44; Veröffentlichungen der Internationalen Historischen Kommission zur Erforschung des Deutschen Ordens. 4) Marburg: N. G. Elwert Verlag 1993. VIII, 311 S.

Large scale chromatographic separations using continuous displacement chromatography (CDC)

International Nuclear Information System (INIS)

Taniguchi, V.T.; Doty, A.W.; Byers, C.H.

1988-01-01

A process for large scale chromatographic separations using a continuous chromatography technique is described. The process combines the advantages of large scale batch fixed column displacement chromatography with conventional analytical or elution continuous annular chromatography (CAC) to enable large scale displacement chromatography to be performed on a continuous basis (CDC). Such large scale, continuous displacement chromatography separations have not been reported in the literature. The process is demonstrated with the ion exchange separation of a binary lanthanide (Nd/Pr) mixture. The process is, however, applicable to any displacement chromatography separation that can be performed using conventional batch, fixed column chromatography

Benjamin Ortmeyer: Mythos und Pathos statt Logos und Ethos, Zu den Publikationen führender Erziehungswissenschaftler in der NS-Zeit: Eduard Spranger, Herman Nohl, Erich Weniger und Peter Petersen, Weinheim / Basel: Beltz 2009 [Rezension

OpenAIRE

Zimmer, Hasko

2010-01-01

Rezension von: Benjamin Ortmeyer: Mythos und Pathos statt Logos und Ethos, Zu den Publikationen führender Erziehungswissenschaftler in der NS-Zeit: Eduard Spranger, Herman Nohl, Erich Weniger und Peter Petersen, Weinheim / Basel: Beltz 2009, 606 S.

Overview of online two-dimensional liquid chromatography based on cell membrane chromatography for screening target components from traditional Chinese medicines.

Science.gov (United States)

Muhammad, Saqib; Han, Shengli; Xie, Xiaoyu; Wang, Sicen; Aziz, Muhammad Majid

2017-01-01

Cell membrane chromatography is a simple, specific, and time-saving technique for studying drug-receptor interactions, screening of active components from complex mixtures, and quality control of traditional Chinese medicines. However, the short column life, low sensitivity, low column efficiency (so cannot resolve satisfactorily mixture of compounds), low peak capacity, and inefficient in structure identification were bottleneck in its application. Combinations of cell membrane chromatography with multidimensional chromatography such as two-dimensional liquid chromatography and high sensitivity detectors like mass have significantly reduced many of the above-mentioned shortcomings. This paper provides an overview of the current advances in online two-dimensional-based cell membrane chromatography for screening target components from traditional Chinese medicines with particular emphasis on the instrumentation, preparation of cell membrane stationary phase, advantages, and disadvantages compared to alternative approaches. The last section of the review summarizes the applications of the online two-dimensional high-performance liquid chromatography based cell membrane chromatography reported since its emergence to date (2010-June 2016). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of radioactive mixed hazardous waste using derivatization gas chromatography/mass spectrometry, liquid chromatography, and liquid chromatography/mass spectrometry

International Nuclear Information System (INIS)

Campbell, J.A.; Lerner, B.D.; Bean, R.M.; Grant, K.E.; Lucke, R.B.; Mong, G.M.; Clauss, S.A.

1994-08-01

Six samples of core segments from Tank 101-SY were analyzed for chelators, chelator fragments, and several carboxylic acids by derivatization gas chromatography/mass spectrometry. The major components detected were ethylenediaminetetraacetic acid, nitroso-iminodiacetic acid, nitrilotriacetic acid, citric acid, succinic acid, and ethylenediaminetriacetic acid. The chelator of highest concentration was ethylenediaminetetraacetic acid in all six samples analyzed. Liquid chromatography was used to quantitate low molecular weight acids including oxalic, formic, glycolic, and acetic acids, which are present in the waste as acid salts. From 23 to 61% of the total organic carbon in the samples analyzed was accounted for by these acids

Gas chromatography in space

Science.gov (United States)

Akapo, S. O.; Dimandja, J. M.; Kojiro, D. R.; Valentin, J. R.; Carle, G. C.

1999-01-01

Gas chromatography has proven to be a very useful analytical technique for in situ analysis of extraterrestrial environments as demonstrated by its successful operation on spacecraft missions to Mars and Venus. The technique is also one of the six scientific instruments aboard the Huygens probe to explore Titan's atmosphere and surface. A review of gas chromatography in previous space missions and some recent developments in the current environment of fiscal constraints and payload size limitations are presented.

Counter-current motion in counter-current chromatography.

Science.gov (United States)

Ito, Yoichiro

2014-12-12

After the CCC2012 meeting, I have received an e-mail regarding the terminology of "Countercurrent Chromatography". It stated that the term "Countercurrent" is a misnomer, because its stationary phase is motionless in the column and that the method should be renamed as liquid-liquid separations or centrifugal separations. However, it was found that these names are already used for various other techniques as found via Google search. The term "Countercurrent Chromatography" was originally made after two preparative methods of Countercurrent distribution and liquid Chromatography, both having no countercurrent motion in the column. However, it is surprising to find that this F1 hybrid method "Countercurrent Chromatography" can clearly exhibit countercurrent motion within the separation column in both hydrodynamic and hydrostatic equilibrium systems. This justifies that "Countercurrent Chromatography" is a proper term for this chromatographic method. Published by Elsevier B.V.

Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

International Nuclear Information System (INIS)

Shu, Xikai; Wang, Mei; Liu, Daicheng; Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi

2013-01-01

An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-β-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-β-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

Energy Technology Data Exchange (ETDEWEB)

Shu, Xikai; Wang, Mei; Liu, Daicheng [College of Life Science, Shandong Normal University, Jinan, Shandong (China); Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi, E-mail: wxjn1998@126.com [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China)

2013-09-01

An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-{beta}-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-{beta}-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

Micellar liquid chromatography

International Nuclear Information System (INIS)

Basova, Elena M; Ivanov, Vadim M; Shpigun, Oleg A

1999-01-01

Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

Analytical chromatography. Methods, instrumentation and applications

International Nuclear Information System (INIS)

Yashin, Ya I; Yashin, A Ya

2006-01-01

The state-of-the-art and the prospects in the development of main methods of analytical chromatography, viz., gas, high performance liquid and ion chromatographic techniques, are characterised. Achievements of the past 10-15 years in the theory and general methodology of chromatography and also in the development of new sorbents, columns and chromatographic instruments are outlined. The use of chromatography in the environmental control, biology, medicine, pharmaceutics, and also for monitoring the quality of foodstuffs and products of chemical, petrochemical and gas industries, etc. is considered.

Chromatography: Are We Getting It Right?

Science.gov (United States)

Maitland, Pamela D.; Maitland, David P.

2002-01-01

Explains the basics of chromatography which is used to demonstrate the separation of plant photosynthetic pigments. Reports the results of an evaluative study that explored textbook errors in explaining how chromatography works. (Contains 13 references.) (Author/YDS)

Stationary phases for superheated water chromatography

International Nuclear Information System (INIS)

Saha, Shikha

2002-01-01

This project focused on the comparison of conventional liquid chromatography and superheated water chromatography. It examined the differences in efficiency and retention of a range of different stationary phases. Alkyl aryl ketones and eight aromatic compounds were separated on PBD-zirconia, Xterra RP 18, Luna C 18 (2) and Oasis HLB columns using conventional LC and superheated water chromatography system. The retention indices were determined in the different eluents. On changing the organic component of the eluent from methanol to acetonitrile to superheated water considerable improvements were found in the peak shapes and column efficiencies on the PBD-zirconia and Oasis HLB columns. PS-DVB, PBD-zirconia and Xterra RP 18 columns have been used in efficiency studies. It was found that simply elevating the column temperature did not increase the efficiency of a separation in superheated water chromatography. The efficiency depended on flow rate, injection volume and also mobile phase preheating system. Although high efficiencies were not achieved with superheated water on PS-DVB and Xterra RP 18 columns, a higher efficiency was achieved on a PBD-zirconia column with superheated water than with 25-35% ACN at room temperature. The proposed theoretical increases in u opt were measured on three columns using superheated water as the mobile phase. The application of the superheated water chromatographic method to the separation of the pungent constituents of ginger by superheated water chromatography-NMR coupling system was studied. The coupling of superheated water chromatography using deuterium oxide to NMR spectroscopy for the separation of dry ginger extract was successful, although the NMR sensitivity in on-line mode coupling system was low. However, four compounds were identified in the ginger extract by stop-flow mode on superheated water chromatography-UV-NMR detection system. (author)

Atomic Force Microscope Mediated Chromatography

Science.gov (United States)

Anderson, Mark S.

2013-01-01

The atomic force microscope (AFM) is used to inject a sample, provide shear-driven liquid flow over a functionalized substrate, and detect separated components. This is demonstrated using lipophilic dyes and normal phase chromatography. A significant reduction in both size and separation time scales is achieved with a 25-micron-length column scale, and one-second separation times. The approach has general applications to trace chemical and microfluidic analysis. The AFM is now a common tool for ultra-microscopy and nanotechnology. It has also been demonstrated to provide a number of microfluidic functions necessary for miniaturized chromatography. These include injection of sub-femtoliter samples, fluidic switching, and sheardriven pumping. The AFM probe tip can be used to selectively remove surface layers for subsequent microchemical analysis using infrared and tip-enhanced Raman spectroscopy. With its ability to image individual atoms, the AFM is a remarkably sensitive detector that can be used to detect separated components. These diverse functional components of microfluidic manipulation have been combined in this work to demonstrate AFM mediated chromatography. AFM mediated chromatography uses channel-less, shear-driven pumping. This is demonstrated with a thin, aluminum oxide substrate and a non-polar solvent system to separate a mixture of lipophilic dyes. In conventional chromatographic terms, this is analogous to thin-layer chromatography using normal phase alumina substrate with sheardriven pumping provided by the AFM tip-cantilever mechanism. The AFM detection of separated components is accomplished by exploiting the variation in the localized friction of the separated components. The AFM tip-cantilever provides the mechanism for producing shear-induced flows and rapid pumping. Shear-driven chromatography (SDC) is a relatively new concept that overcomes the speed and miniaturization limitations of conventional liquid chromatography. SDC is based on a

Optimizing separations in online comprehensive two‐dimensional liquid chromatography

Science.gov (United States)

Gargano, Andrea F.G.; Schoenmakers, Peter J.

2017-01-01

Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high‐molecular‐weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one‐dimensional liquid chromatography, two‐dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two‐dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two‐dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two‐dimensional liquid chromatography separations. PMID:29027363

Extraction chromatography of actinides

International Nuclear Information System (INIS)

Muller, W.

1978-01-01

Extraction chromatography of actinides in the oxidation state from 2 to 6 is reviewed. Data on using neutral (tbp), basic (substituted ammonium salts) and acidic [di-(2-ethylhexyl)-phosphoric acid (D2EHPA)] extracting agents ketones, esters, alcohols and β-diketones in this method are given. Using the example of actinide separation using D2EHPA, discussed are factors influencing the efficiency of their chromatography separation (nature and particle size of the carrier materials, extracting agents amount on the carrier, temperature and elution rate)

Purification of lignans from Fructus Arctii using off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography.

Science.gov (United States)

Yang, Bichao; Xin, Huaxia; Wang, Feier; Cai, Jianfeng; Liu, Yanfang; Fu, Qing; Jin, Yu; Liang, Xinmiao

2017-08-01

As a common traditional Chinese medicine, Fructus Arctii has important clinical medical values. Its main components are lignans, which are difficult to separate and analyze because of the complex composition, similar chemical structures, and close properties. In this study, an off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography method, as well as an effective sample pretreatment method based on hydrophilic interaction chromatography material, was developed to enrich the minor lignan fractions and obtain high-purity compounds. In total, 12 high-purity compounds were isolated from Fructus Arctii. Their structures were identified by using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, which showed that all were lignans and that most of them were isomers. The results demonstrated the effective off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography method for the purification of lignans from Fructus Arctii. The separation protocol established here will be beneficial for the separation of complex samples from other kinds of natural products. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimizing separations in online comprehensive two-dimensional liquid chromatography.

Science.gov (United States)

Pirok, Bob W J; Gargano, Andrea F G; Schoenmakers, Peter J

2018-01-01

Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations. © 2017 The Authors. Journal of Separation Science published by WILEY-VCH Verlag GmbH & Co. KGaA.

Rezension zu: Thomas Ballhausen, Thomas Edlinger, Linda Henschel, Katherina Zakrawsky: The Porn Identity. Expeditionen in die Dunkelzone. Nürnberg: Verlag für Moderne Kunst 2009.

Directory of Open Access Journals (Sweden)

Florian Cramer

2010-02-01

Full Text Available Die Ausstellung „The Porn Identity“ und ihr begleitender Katalog- und Essayband kartografieren die Schnittmengen von Pornografie, zeitgenössischer Kunst und Kulturtheorie umfassend genug, um als Einführungen ins Themengebiet nützlich zu sein. Indem der Katalog Pornobilder und -lifestyle zugleich schwelgerisch zelebriert und genderpolitisch-korrekt verbrämt, ist er jedoch so schmierig wie kommerzielle Pornografie. Dies macht ihn zum Konzeptkunstwerk – und setzt Fragezeichen hinter den Diskurs der porn studies.

Ion mobility: its role in plasma chromatography

International Nuclear Information System (INIS)

Mason, E.A.

1984-01-01

This paper is a review of the basic physical theory underlying plasma chromatography. Essentially, plasma chromatography simply measures ion mobility. The new feature of plasma chromatography, as compared to aqueous electrophoresis, is the existence of a highly-developed and accurate body of theory that connects gaseous ion mobility and diffusion to the ion molecule interactions in the drift tube. Attention is restricted to phenomena occurring in the drift tube portion of the apparatus

„Ich glaube, wir können es uns gar nicht leisten, nichts von Religion zu verstehen.“ Grundkompetenzen für Lehrerinnen und Lehrer im Umgang mit Religion

Directory of Open Access Journals (Sweden)

Helga Kohler-Spiegel

2016-06-01

Full Text Available Das Recht von Kindern, sich mit Religion auseinanderzusetzen, ist in den Kinderrechten der UN verankert, Friedrich Schweitzer spricht von den „großen Fragen“. Diesen Fragen Raum zu geben beinhaltet ein Begleiten der Kinder, unabhängig ihrer formalen religiösen Zugehörigkeiten. Da sich Religiöses in der Schule auf sehr vielfältige Art zeigt, bedarf es der kurzen Klärung, was darunter verstanden wird, bevor beschrieben wird, welche Grundkompetenzen Lehrpersonen brauchen, um Kinder in der Vielfalt dieser Erfahrungen und Fragen zu begleiten. „I believe we cannot afford to not understand religion.“ Basic competences for teachers in handling religion Children‘s entitlement to deal with religion is constituted in the Human Rights for Children of the UN, Friedrich Schweitzer refers to it as „The big questions“. To create space for these questions implies to shepherd the children, regardless of their formal religious affiliation. Driven by the diversity of religiousness in school, some brief clarification of this topic is required, before characterizing which basic expertise educational personnel need to have in order to guide children through the variety of these experiences and questions.

Ion Chromatography Applications in Wastewater Analysis

Directory of Open Access Journals (Sweden)

Rajmund Michalski

2018-02-01

Full Text Available Wastewater analysis is an important area in analytical and environmental chemistry. It can be performed with both the classic wet methods and instrumental techniques. The development of new methods, and modification of the existing ones, constitute a major task for researchers. Ion chromatography plays a predominant role in ion determinations with the instrumental methods. It offers several advantages over the conventional methods, such as simultaneous determinations of alkali and alkaline earth cations and ammonia. Ammonium ions cannot be determined by spectroscopic methods. Ion chromatography has been accepted world-wide as a reference method for analyzing anions and cations in water and wastewater due to the fact that it enables the replacement of several individual wet chemistry methods for common ions with one instrumental technique. The following article describes the principles of ion chromatography, such as stationary phases, eluents, detectors, and sample preparation methods. Moreover, the applications of ion chromatography in wastewater analyses and international standards are presented.

Towards early detection of the hydrolytic degradation of poly(bisphenol A)carbonate by hyphenated liquid chromatography and comprehensive two-dimensional liquid chromatography

NARCIS (Netherlands)

Coulier, L.; Kaal, E.R.; Hankemeier, Th.

2006-01-01

The hydrolytic degradation of poly(bisphenol A)carbonate (PC) has been characterized by various liquid chromatography techniques. Size exclusion chromatography (SEC) showed a significant decrease in molecular mass as a result of hydrolytic degradation, while 'liquid chromatography at critical

Airtight miniaturized chromatography: a safer method for radiopharmaceutical quality control

International Nuclear Information System (INIS)

Coupal, J.J.; Shih, W.J.; Ryo, U.Y.

1988-01-01

Miniaturized chromatography is widely used for quality control of radiopharmaceuticals. Recently, published chromatography procedures have illustrated or described chromatography chambers open to the air in use, suggesting that volatile toxic mobile phases are harmless to people in the vicinity. The authors describe the results of their search for an inexpensive closed chromatography chamber that can be used to derive safely the benefits from conventional miniaturized chromatography

Physical interactions in MRI. Some rules of thumb for their reduction; Physikalische Wechselwirkungen in der MRT. Einige Daumenregeln zu ihrer Reduktion

Energy Technology Data Exchange (ETDEWEB)

Muehlenweg, M. [Krankenhaus Martha-Maria Halle-Doelau, Institut fuer Radiologie, Halle (Saale) (Germany); Schaefers, G. [MR:comp GmbH, Gelsenkirchen (Germany); Trattnig, S. [Medizinische Universitaet Wien, Exzellenzzentrum Hochfeld-Magnetresonanz, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria)

2015-08-15

Magnetic resonance imaging (MRI) is one of the most powerful and at the same time gentlest clinical imaging techniques at the present time; however, the enormous physical complexity as well as simple inattentiveness (projectile effect) implicate a significant risk potential and place high demands on the MR operator to ensure a safe workflow. A sound knowledge of the potential MR interactions is the foundation for a safe and profitable operation for all parties. The first part of this article deals with the three most important sources of physical interaction, i.e. static magnetic field, gradient and high-frequency (HF) fields. The paper discusses the differences between each type of field with respect to the impact on human beings, the interactions with magnetic and electrically conducting objects/implants and the relevant safety standards. Each section is followed by simple rules of thumb to minimize potentially unwanted physical MRI interactions. (orig.) [German] Die Magnetresonanztomographie ist eines der leistungsfaehigsten und zugleich schonendsten klinischen bildgebenden Verfahren der heutigen Zeit. Allerdings bergen ihre enorme physikalische Komplexitaet, aber auch einfache Unaufmerksamkeiten (''Projektileffekt'') ein signifikantes Risikopotenzial in sich und stellen hohe Anforderungen an die MR-Bediener, um einen sicheren Betrieb zu gewaehrleisten. Ein solides Wissen um die potenziellen MR-Wechselwirkungen ist die Grundlage fuer einen sicheren und fuer alle Seiten gewinnbringenden Betrieb. Der erste Teil der Arbeit behandelt die 3 zentralen Quellen fuer physikalische Wechselwirkungen in der Magnetresonanztomographie (statisches Magnetfeld, geschaltete Gradienten- und HF-Felder). Es werden fuer jede Feldart die Auswirkungen auf den Menschen, Wechselwirkungen mit magnetischen und elektrisch leitenden Objekten/Implantaten und relevante Sicherheitsstandards besprochen. Daran angeschlossen ist jeweils ein Abschnitt mit einfachen &apos

Isolation and purification of six iridoid glycosides from gardenia jasminoides fruit by medium-pressure liquid chromatography combined with macroporous resin chromatography.

Science.gov (United States)

Wang, Yun; Liu, Hui; Shen, Lifeng; Yao, Lan; Ma, Yinlian; Yu, Dingrong; Chen, Jianhong; Li, Puling; Chen, Ying; Zhang, Cun

2015-12-01

Gardeniae fructus is one of the most frequently used herbs in traditional Chinese medicine. In the present study, a process for the enrichment of six iridoid glycosides from Gardeniae fructus was developed using medium-pressure liquid chromatography combined with macroporous resin and reversed-phase chromatography. The purities of different fractions from Gardeniae fructus were assessed using quantitative high-performance liquid chromatography. After fractionation using HPD-100 column chromatography, a 30% ethanol fraction was selected based on high-performance liquid chromatography and liquid chromatography with mass spectrometry qualitative analysis to separate and purify. Based on the orientation analysis results, six compounds-deacetyl asperulosidic acid methyl ester, gardenoside, ixoroside, scandoside methyl ester, genipin-1-O-β-d-gentiobioside, and geniposide-were successfully isolated and purified in three to four combined steps from Gardeniae fructus. The purities of these compounds were found by high-performance liquid chromatography analysis to be 97.9, 98.1, 95.5, 96.3, 97.1, and 98.7%, respectively. Moreover, their structures were elucidated by NMR spectroscopy and liquid chromatography with tandem mass spectrometry. The separation process was highly efficient, rapid, and accurate, making it a potential approach for the large-scale production of iridoids in the laboratory and providing several marker compounds for quality control. This procedure may be meaningful for the purification of other natural products used in traditional Chinese medicine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimizing separations in online comprehensive two‐dimensional liquid chromatography

OpenAIRE

Pirok, Bob W.J.; Gargano, Andrea F.G.; Schoenmakers, Peter J.

2017-01-01

Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass...

Extraprostatische Expansion des Prostatakarzinoms und seine Beziehung zu den Resektionsrändern bei der radikalen Prostatektomie aus Sicht des Pathologen

Directory of Open Access Journals (Sweden)

Noll P

2008-01-01

Full Text Available Das Prostatakarzinom stellt heute in der westlichen Welt das am häufigsten diagnostizierte Karzinom beim Mann dar. Entsprechend dieser Häufigkeit werden zunehmend radikale Prostatektomien durchgeführt. Die histologische Aufarbeitung des Operationspräparates liefert dem Urologen die wichtigsten Prognosefaktoren des Prostatakarzinoms. Hierbei besteht ein enger Zusammenhang zwischen der extraprostatischen Ausdehnung des Tumors und seiner Beziehung zu den Resektionsrändern. Anhand einer eigenen Untersuchung an 200 radikal operierten Prostatakarzinomen konnte gezeigt werden, dass hierbei die Lokalisation, der Malignitätsgrad und die Größe des Tumors entscheidende Bedeutung haben. Die Ermittlung dieser Parameter ist abhängig von einer standardisierten Untersuchungstechnik auf der Grundlage einer vollständigen histologischen Aufarbeitung der Prostata.

Tutorium Quantenfeldtheorie was Sie schon immer über QFT wissen wollten, aber bisher nicht zu fragen wagten

CERN Document Server

Edelhäuser, Lisa

2016-01-01

Dieses Buch richtet sich an alle, die sich schon immer gefragt haben, wie die kanonische Quantisierung, die LSZ-Reduktionsformel, Pfadintegrale, Feynman-Graphen und die Renormierung miteinander zusammenhängen. Als locker geschriebene Begleitlektüre zu Vorlesungen über Quantenfeldtheorie oder zum Selbststudium geeignet, gibt sich das Buch gesprächig und liefert Rechentricks und Erklärungen, die für Einsteiger sehr hilfreich sind. Im ersten Teil werden anhand von Skalarfeldern grundlegende Konzepte von der klassischen Feldtheorie bis zur Renormierung eingeführt. Der zweite Teil verallgemeinert diese für Felder mit Spin und legt mit der Einführung des Eichprinzips die Grundlagen für den dritten Teil. Hier werden „Anwendungen auf die reale Welt“ behandelt: Die Quantenelektrodynamik und ihre Renormierung, sowie das Standardmodell der Teilchenphysik und der Higgs-Mechanismus. Durch ausführlich vorgerechnete und in den Text eingebundene Aufgaben eignet sich das Tutorium sowohl zum schnellen Nachschla...

Extraction chromatography of fission products

International Nuclear Information System (INIS)

Bonnevie-Svendsen, M.; Goon, K.

1978-01-01

Various cases of using extraction chromatography during analysis of fission products are reviewed. The use of the extraction chromatography method is considered while analysing reprocessed products of nuclear fuel for quantitative radiochemical analysis and control of fission product and actinoide separation during extraction and their chemical state in production solutions. The method is used to obtain pure fractions of typical burnup monitors (neodymium, molybdenum, cerium, cesium, europium, lanthanides) during determination of nuclear fuel burnup degree. While studying the nature of nuclear reactions the method is used to separate quickly short-life isotopes, to purify β-radiator fractions before measuring their half-life periods, to enrich isotopes forming with low output during fission. Examples of using extraction chromatography are given to separate long half-life or stable fission products from spent solutions, to control environment object contamination

Studies on the turnover and properties of dump groundwaters in brown coal mining areas and possibilities of influencing them. Final report; Untersuchungen zum Stoffumsatz und zur Beschaffenheit der Kippengrundwaesser in Braunkohlebergbaugebieten und Moeglichkeiten zu deren Beeinflussung. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Katzur, J.; Liebner, F.; Liebner, C.; Welzel, H.P.; Hettrich, K.

2001-07-01

Only 6 days after the increase in pH with water saturation the concentration of iron in the pore water of the T1 sediment had dropped to a low value, 70% of which was accounted for by Fe(II). This is probably due to the almost complete precipitation of Fe(III) caused by the high pH values. Compared with the untreated variant the lowering of pH in the further course of the experiment led to a slight Fe(III) mobilisation and hence, through interaction with other reduction processes, to erratic changes in the share of Fe(II) in total Fe. Although this sediment showed a relatively low iron concentration a comparison showed that higher pH values and incubation temperatures have an influence on microbial iron reduction. [German] Im Porenwasser des Sedimentes T1 lag Eisen bereits 6 Tage nach pH-Erhoehung und Wassersaettigung nur noch in geringer Konzentration und zu ueber 70% als Fe(II) vor. Dies ist vermutlich in erster Linie auf die nahezu vollstaendige Ausfaellung von Fe(III) infolge der hohen pH-Werte zurueckzufuehren. Im weiteren Versuchsverlauf fuehrte das Absinken der pH-Werte zu einer im Vergleich zur unbehandelten Variante geringfuegigen Fe(III)-Mobilisierung und damit in Wechselwirkung mit ablaufenden Reduktionsprozessen zu unstetigen Veraenderungen in den Anteilen Fe(II) an Fe{sub ges}. Obwohl in diesem Sediment nur vergleichsweise niedrige Eisenkonzentrationen vorliegen, ergab ein Vergleich, dass hoehere pH-Werte und Inkubationtemperaturen die mikrobielle Eisenreduktion beeinflussen. (orig.)

Phytochemical analysis of ethanolic extract of Dichrostachys Cinerea W and Arn leaves by a thin layer chromatography, high performance thin layer chromatography and column chromatography

OpenAIRE

M Vijayalakshmi; K Periyanayagam; K Kavitha; K Akilandeshwari

2013-01-01

Background: The leaves of Dichrostachys cinerea are used as laxative, diuretic, painkiller. It is also used in the treatment of gonorrhoea, boils, oedema, gout, veneral diseases and nasopharyngeal affections, etc. Materials and Methods: The Phytochemical investigation of ethanolic extract of D. cinerea leaves were performed by standard chemical tests, thin layer chromatography (TLC) by using various solvent systems, and by high performance liquid chromatography (HPTLC). Two compounds were...

Alte und neue Problemaspekte der Figur. Zu einem medienübergreifenden Versuch einer Begriffsbestimmung der Figur [Jens Eder / Fotis Jannidis / Ralf Schneider (Hg.: Characters in Fic­tional Worlds. Understanding Imaginary Beings in Literature, Film, and Other Media. Berlin 2010

Directory of Open Access Journals (Sweden)

Carmen Lăcan

2012-12-01

Full Text Available Rezension zu / Review of:Jens Eder / Fotis Jannidis / Ralf Schneider (Hg.: Characters in Fic­tional Worlds. Understanding Imaginary Beings in Literature, Film, and Other Media. Berlin 2010

Vulnerabilität. Erläuterungen zu einem Schlüsselbegriff im Denken Judith Butlers

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Pistrol Florian

2016-07-01

Full Text Available Im neueren Denken Judith Butlers nimmt der Begriff der Vulnerabilität eine Schlüsselrolle ein. Kaum eines der vielen Themen, denen sich die US-amerikanische Autorin seit der Jahrtausendwende widmet, kann ohne Kenntnis ihrer Überlegungen zu diesem Terminus angemessen verstanden werden. Der Versuch einer Rekonstruktion ihrer Konzeption von Vulnerabilität steht allerdings vor der Schwierigkeit, dass Butlers Gedanken hierzu über zahlreiche Texte hinweg verstreut sind, wobei bisweilen unterschiedliche Aspekte betont und verschiedene Schwerpunktsetzungen vorgenommen werden. Im vorliegenden Beitrag werden Butlers vulnerabilitätstheoretische Ausführungen in gebündelter Weise dargestellt und interpretiert. Dabei wird (1 die Bedeutsamkeit von Butlers Überlegungen zur Vulnerabilität für ihre Vorstellung von Körperlichkeit aufgewiesen, (2 der Zusammenhang von Vulnerabilität und Anerkennung erläutert und (3 gezeigt, welche ethischen Erwägungen Butler ausgehend von ihrer Anerkennungskonzeption und ihrem Denken der Vulnerabilität anstellt und inwiefern Vulnerabilität und politische Handlungsfähigkeit einander nicht ausschließen. Abschließend wird (4 Butlers Vulnerabilitätsverständnis mit einigen kritischen Rückfragen konfrontiert.

Purification of flavonoids from licorice using an off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method.

Science.gov (United States)

Fan, Yunpeng; Fu, Yanhui; Fu, Qing; Cai, Jianfeng; Xin, Huaxia; Dai, Mei; Jin, Yu

2016-07-01

An orthogonal (71.9%) off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method coupled with effective sample pretreatment was developed for separation and purification of flavonoids from licorice. Most of the nonflavonoids were firstly removed using a self-made Click TE-Cys (60 μm) solid-phase extraction. In the first dimension, an industrial grade preparative chromatography was employed to purify the crude flavonoids. Click TE-Cys (10 μm) was selected as the stationary phase that provided an excellent separation with high reproducibility. Ethyl acetate/ethanol was selected as the mobile phase owing to their excellent solubility for flavonoids. Flavonoids co-eluted in the first dimension were selected for further purification using reversed-phase liquid chromatography. Multiple compounds could be isolated from one normal-phase fraction and some compounds with bad resolution in one-dimensional liquid chromatography could be prepared in this two-dimensional system owing to the orthogonal separation. Moreover, this two-dimensional liquid chromatography method was beneficial for the preparation of relatively trace flavonoid compounds, which were enriched in the first dimension and further purified in the second dimension. Totally, 24 flavonoid compounds with high purity were obtained. The results demonstrated that the off-line two-dimensional liquid chromatography method was effective for the preparative separation and purification of flavonoids from licorice. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of pollutants in air and water using gas chromatography and headspace gas chromatography

Energy Technology Data Exchange (ETDEWEB)

Stenner, H.

1980-01-01

The combination 'personal sampling' with headspace gas chromatography to determine traces of formaldehyde, phenol and benzene in air is investigated in this work, with the aim of developing maximum workplace concentration values (MWL values). Further possible applications of gas chromatography in trace analysis in the environmentally protected area. The analysis of chromium in waste waters (Cr III as acetyl acetonate complex) is investigated as further possible application, whereby optimum conditions are obtained. A modified flame ionization detector was used to increase the detection sensitivity.

Nanoparticle Analysis by Online Comprehensive Two-Dimensional Liquid Chromatography combining Hydrodynamic Chromatography and Size-Exclusion Chromatography with Intermediate Sample Transformation

Science.gov (United States)

2017-01-01

Polymeric nanoparticles have become indispensable in modern society with a wide array of applications ranging from waterborne coatings to drug-carrier-delivery systems. While a large range of techniques exist to determine a multitude of properties of these particles, relating physicochemical properties of the particle to the chemical structure of the intrinsic polymers is still challenging. A novel, highly orthogonal separation system based on comprehensive two-dimensional liquid chromatography (LC × LC) has been developed. The system combines hydrodynamic chromatography (HDC) in the first-dimension to separate the particles based on their size, with ultrahigh-performance size-exclusion chromatography (SEC) in the second dimension to separate the constituting polymer molecules according to their hydrodynamic radius for each of 80 to 100 separated fractions. A chip-based mixer is incorporated to transform the sample by dissolving the separated nanoparticles from the first-dimension online in tetrahydrofuran. The polymer bands are then focused using stationary-phase-assisted modulation to enhance sensitivity, and the water from the first-dimension eluent is largely eliminated to allow interaction-free SEC. Using the developed system, the combined two-dimensional distribution of the particle-size and the molecular-size of a mixture of various polystyrene (PS) and polyacrylate (PACR) nanoparticles has been obtained within 60 min. PMID:28745485

Inert carriers for column extraction chromatography

International Nuclear Information System (INIS)

Katykhin, G.S.

1978-01-01

Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al 2 O 3 ) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

Gel chromatography of sup(99m)Tc-labelled compounds

International Nuclear Information System (INIS)

Vilcek, S.; Machan, V.; Kalincak, M.

1976-01-01

The present state of gel chromatography of sup(99m)Tc-labelled compounds is reviewed. Examples are given of gel chromatography for preparing labelled compounds and for quality control analysis and the development of new types of sup(99m)Tc-labelled compounds. The factors which influence the gel chromatography of these compounds are discussed, i.e., the nature of the elution agent, the duration of the contact of the gel and the preparation the gel type, the nature of the labelled compound. The GCS method (gel chromatography scanning) is briefly described. The advantages of gel chromatography as compared with other chromatographic techniques for sup(99m)Tc-labelled compounds are summarized. (author)

Pedological investigations regarding thermal, chemical and biological soil cleaning techniques. Final report for the period of investigation 1990 to 1994; Bodenkundliche Untersuchungen zu thermischen, chemischen und biologischen Bodenreinigungsverfahren. Schlussbericht fuer den Bearbeitungszeitraum 1990 bis 1994

Energy Technology Data Exchange (ETDEWEB)

Goetz, D; Bauske, B; Claussen, A; Glaeseker, W; Holz, C [Hamburg Univ. (Germany). Inst. fuer Bodenkunde

1998-12-31

The hazard potential of contaminated sites is evaluated by means of risk assessments. These can entail diverse measures being taken that may range from the mere observation of the site over protective and restricting measures, different encapsulations to ensure its safety as well as the shifting of contaminated matter, to the decontamination of the site (Council of Experts on Environmental Questions SRU, 1990). Of these measures, soil cleaning demands the greatest effort and should lastingly repair the damage without new damage being caused in another place. (orig.) [Deutsch] Das Gefaehrdungspotential kontaminierter Standorte wird ueber Gefaehrdungsabschaetzungen klassifiziert. Diese Einschaetzung kann zu verschiedenen Massnahmen fuehren. Sie reichen von der reinen Ueberwachung des Standortes ueber Schutz- und Beschraenkungsmassnahmen, Sicherung durch verschiedene Einkapselungen, Umlagerungsmassnahmen bis zur Dekontamination der verunreinigten Materialien (SRU, 1990). Die Bodenreinigung ist dabei die aufwendigste Massnahme und sollte zu einer endgueltigen Beseitigung des Schadens fuehren, ohne dass an anderer Stelle neue Lasten entstehen. (orig.)

XII All-Russian conference on gas chromatography. Program. Summary of reports

International Nuclear Information System (INIS)

2002-01-01

Program and summary of reports of the XII All-Russian conference on gas chromatography are performed. The conference took place in Samara, 10-14 June, 2002. Reports on physicochemical regularities of gas chromatography, application of chromatographic methods in atomic energetics are included in the program of the conference. Part of the reports are deleted to the analytical application of the gas chromatography. Adsorbents for the gas chromatography, complex methods, mathematic methods in chromatography, ecological aspects of the gas chromatography [ru

Rezension zu: Sabine Hark, Paula-Irene Villa (Hg.: Anti-Genderismus. Sexualität und Geschlecht als Schauplätze aktueller politischer Auseinandersetzungen. Bielefeld: transcript Verlag 2015.

Directory of Open Access Journals (Sweden)

Christian Hammermann

2017-05-01

Full Text Available Der von Sabine Hark und Paula-Irene Villa herausgegebene Sammelband analysiert die öffentlichen Angriffe auf Gender Studies und Gender Mainstreaming, die unter dem Begriff Anti-Genderismus auftreten und verhandelt werden. Die einzelnen Beiträge untersuchen Themen und Methoden des anti-genderistischen Diskurses, seine Akteur_Innen und gesellschaftlichen Bedingung. Dabei entwerfen sie ein sehr kohärentes Porträt dieser Politiken, das allerdings von einer weiteren Untersuchung der gesellschaftlichen Bedingungen und intersektionalen Bezüge zu anderen Ressentiments profitieren würde.

Peak broadening in paper chromatography and related techniques : III. Peak broadening in thin-layer chromatography on cellulose powder

NARCIS (Netherlands)

Ligny, C.L. de; Remijnse, A.G.

1968-01-01

The mechanism of peak broadening in thin-layer chromatography on cellulose powder was investigated by comparing the peak widths obtained in chromatography with those caused only by diffusion in the cellulose powder, for a set of amino acids of widely differing RF values and six kinds of cellulose

Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

Science.gov (United States)

Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

2015-07-14

Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Chromium Speciation Analysis by Ion Chromatography Coupled ...

African Journals Online (AJOL)

Two methods coupling ion chromatography with inductively coupled plasma - optical emission spectroscopy (ICP-OES) were developed for the simultaneous separation and determination of Cr(III) and Cr(VI) species. In the first method, anion chromatography with sodium bicarbonate/carbonate solution as the eluent was ...

Instrument platforms for nano liquid chromatography.

Science.gov (United States)

Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

2015-11-20

The history of liquid chromatography started more than a century ago and miniaturization and automation are two leading trends in this field. Nanocolumn liquid chromatography (nano LC) and largely synonymous capillary liquid chromatography (capillary LC) are the most recent results of this process where miniaturization of column dimensions and sorbent particle size play crucial role. Very interesting results achieved in the research of extremely miniaturized LC columns at the end of the last century lacked distinctive raison d'être and only advances in mass spectrometry brought a real breakthrough. Configuration of nano LC-electrospray ionization mass spectrometry (LC-ESI-MS) has become a basic tool in bioanalytical chemistry, especially in proteomics. This review discusses and summarizes past and current trends in the realization of nano liquid chromatography (nano LC) platforms. Special attention is given to the mobile phase delivery under nanoflow rates (isocratic, gradient) and sample injection to the nanocolumn. Available detection techniques applied in nano LC separations are also briefly discussed. We followed up the key themes from the original scientific reports over gradual improvements up to the contemporary commercial solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

Rezension zu: Sheila Jeffreys: The Industrial Vagina. The Political Economy of the Global Sex Trade. London: Routledge 2008.

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Susanne Hofmann

2010-02-01

Full Text Available Sheila Jeffreys analysiert die Prozesse, die zu einer Industrialisierung und Globalisierung von Prostitution im späten 20. und 21. Jahrhundert geführt haben. Hauptverantwortlich für die gegenwärtige Diskursverschiebung um Prostitution ist für Jeffreys zum einen die sexuelle Revolution der 1970er Jahre und zum anderen die massive Finanzierung von Unterstützer/-innen der Sexarbeiterinnen zur HIV-Prävention in den 1980ern. Jeffreys legt wie in früheren Arbeiten ihre radikal-feministische Position dar und fordert eine Abschaffung der Prostitution. In ihrer Abrechnung mit dem liberalen feministischen Diskurs, für den eine Unterstützung von Sexarbeiterinnen prioritär ist, ignoriert sie die Widersprüchlichkeiten und Komplexitäten der gelebten Realitäten. An vielen Stellen ihres Buches bekräftigt Jeffreys stereotypische Männlichkeitsvorstellungen, was durch einen Blick über den Tellerrand des ihr vertrauten wissenschaftlichen Bezugsrahmens hätte vermieden werden können.

Gerechtigkeit, ethische Subjektivität und Alterität. Zu den normativen Implikationen der Philosophie von Emmanuel Levinas

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Seitz Sergej

2016-07-01

Full Text Available Obwohl seit einiger Zeit ein verstärktes Forschungsinteresse an Emmanuel Levinas’ Denken des Politischen, verbunden mit einer genaueren Inblicknahme der zentralen Begriffe des Dritten und der Gerechtigkeit aufgekommen ist, blieb bislang unklar, inwiefern aus Levinas’ intrinsisch ‚ethischem‘ Denken in konkreterer Weise normative Konsequenzen zu ziehen sind. Diesem Desiderat versucht der vorliegende Beitrag nachzukommen. Das Levinas’sche Gerechtigkeitsdenken wird dabei so eingeführt, dass es zugleich als alternativer Entwurf und als produktive kritische Provokation für gegenwärtige Gerechtigkeitstheorien lesbar wird. Ausgehend von einer Rekonstruktion des alteritären Verständnisses ethischer Subjektivität, wie es Levinas insbesondere in Jenseits des Seins erarbeitet, wird ausgelotet, wie tragfähig Levinas’ ethische Konzeption plural alteritär durchfurchter Subjektivität für normative Gerechtigkeitsfragen ist. Aus einer Reflexion auf den Begriff des ‚Dritten‘ werden einige konkrete Konsequenzen für das Denken gerechter Institutionen gezogen.

Schinus terebinthifolius countercurrent chromatography (Part III): Method transfer from small countercurrent chromatography column to preparative centrifugal partition chromatography ones as a part of method development.

Science.gov (United States)

das Neves Costa, Fernanda; Hubert, Jane; Borie, Nicolas; Kotland, Alexis; Hewitson, Peter; Ignatova, Svetlana; Renault, Jean-Hugues

2017-03-03

Countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC) are support free liquid-liquid chromatography techniques sharing the same basic principles and features. Method transfer has previously been demonstrated for both techniques but never from one to another. This study aimed to show such a feasibility using fractionation of Schinus terebinthifolius berries dichloromethane extract as a case study. Heptane - ethyl acetate - methanol -water (6:1:6:1, v/v/v/v) was used as solvent system with masticadienonic and 3β-masticadienolic acids as target compounds. The optimized separation methodology previously described in Part I and II, was scaled up from an analytical hydrodynamic CCC column (17.4mL) to preparative hydrostatic CPC instruments (250mL and 303mL) as a part of method development. Flow-rate and sample loading were further optimized on CPC. Mobile phase linear velocity is suggested as a transfer invariant parameter if the CPC column contains sufficient number of partition cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Ionic liquid stationary phases for gas chromatography.

Science.gov (United States)

Poole, Colin F; Poole, Salwa K

2011-04-01

This article provides a summary of the development of ionic liquids as stationary phases for gas chromatography beginning with early work on packed columns that established details of the retention mechanism and established working methods to characterize selectivity differences compared with molecular stationary phases through the modern development of multi-centered cation and cross-linked ionic liquids for high-temperature applications in capillary gas chromatography. Since there are many reviews on ionic liquids dealing with all aspects of their chemical and physical properties, the emphasis in this article is placed on the role of gas chromatography played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity range and temperature-operating range of columns for gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

Science.gov (United States)

Kissinger, Peter T.; And Others

1977-01-01

Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

Isotopic separation by ion chromatography

International Nuclear Information System (INIS)

Albert, M.G.; Barre, Y.; Neige, R.

1994-01-01

The isotopic exchange reaction and the isotopic separation factor are first recalled; the principles of ion chromatography applied to lithium isotope separation are then reviewed (displacement chromatography) and the process is modelled in the view of dimensioning and optimizing the industrial process; the various dimensioning parameters are the isotopic separation factor, the isotopic exchange kinetics and the material flow rate. Effects of the resin type and structure are presented. Dimensioning is also affected by physico-chemical and hydraulic parameters. Industrial implementation features are also discussed. 1 fig., 1 tab., 5 refs

Christine Löw: Frauen aus der Dritten Welt und Erkenntniskritik? Die postkolonialen Untersuchungen von Gayatri C. Spivak zu Globalisierung und Theorieproduktion. Sulzbach im Taunus: Ulrike Helmer Verlag 2009.

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Heike Kahlert

2011-07-01

Full Text Available Christine Löw setzt sich in ihrer politikwissenschaftlichen Dissertation mit dem postkolonial-feministischen Denken Gayatri C. Spivaks auseinander und zielt in ihren sorgfältigen, überwiegend affirmativen Ausführungen darauf, Spivaks Überlegungen für die Politikwissenschaft nutzbar zu machen. Hierzu diskutiert sie deren theoretische Verortung in kritischen Ansätzen von Marxismus, Feminismus und Dekonstruktion sowie ihre Reflexionen zur epistemischen Gewalt westlichen Denkens gegenüber dem Süden und illustriert ihre Thesen zur Subalternität an vier ausgewählten politischen Themenfeldern. Zentrale Verdienste des Buches liegen darin, Spivaks Arbeiten in den deutschsprachigen sozialwissenschaftlichen Kontext einzuschreiben und weiterführende Forschungsfragen zu Globalisierung und Erkenntnisproduktion aufzuwerfen.Christine Löw’s dissertation (in the field of Political Science examines Gayatri C. Spivak’s postcolonial-feminist thinking. In her careful, mainly affirmative explanations she aims at utilizing Spivak’s considerations for Political Science. To this end, she discusses their theoretical position within critical approaches of Marxism, feminism, and deconstruction as well as her reflections on epistemic violence of western thinking against the south while also illustrating her theses on subalternity with four selected political topics. Situating Spivak’s works within the context of German-speaking social science and posing additional research questions on globalization and production of knowledge are the main achievements of this book.

PHARMACEUTICAL AND BIOMEDICAL APPLICATIONS OF AFFINITY CHROMATOGRAPHY: RECENT TRENDS AND DEVELOPMENTS

Science.gov (United States)

Hage, David S.; Anguizola, Jeanethe A.; Bi, Cong; Li, Rong; Matsuda, Ryan; Papastavros, Efthimia; Pfaunmiller, Erika; Vargas, John; Zheng, Xiwei

2012-01-01

Affinity chromatography is a separation technique that has become increasingly important in work with biological samples and pharmaceutical agents. This method is based on the use of a biologically-related agent as a stationary phase to selectively retain analytes or to study biological interactions. This review discusses the basic principles behind affinity chromatography and examines recent developments that have occurred in the use of this method for biomedical and pharmaceutical analysis. Techniques based on traditional affinity supports are discussed, but an emphasis is placed on methods in which affinity columns are used as part of HPLC systems or in combination with other analytical methods. General formats for affinity chromatography that are considered include step elution schemes, weak affinity chromatography, affinity extraction and affinity depletion. Specific separation techniques that are examined include lectin affinity chromatography, boronate affinity chromatography, immunoaffinity chromatography, and immobilized metal ion affinity chromatography. Approaches for the study of biological interactions by affinity chromatography are also presented, such as the measurement of equilibrium constants, rate constants, or competition and displacement effects. In addition, related developments in the use of immobilized enzyme reactors, molecularly imprinted polymers, dye ligands and aptamers are briefly considered. PMID:22305083

Gestaltung einer netzbasierten Lernumgebung für einen Fernstudiengang zu „Medien und Informationstechnologien in Erziehung, Unterricht und Bildung“

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Gerhard Tulodziecki

2017-07-01

Full Text Available In diesem Beitrag stelle ich dar, wie wir in einem kooperativen Verbund eine netzbasierte Lernumgebung für einen Fernstudiengang zu „Medien und Informationstechnologien in Erziehung, Unterricht und Bildung“ gestalten. Das Projekt wird von zwei Arbeitsgruppen an der Universität Paderborn (Allgemeine Didaktik und Medienpädagogik, Didaktik der Informatik und einer Arbeitsgruppe an der Fernuniversität Hagen (Theorie der Schule und des Unterrichts getragen. Die Projektleitung teile ich mit Horst Dichanz, Bardo Herzig und Johannes Magenheim. Der Fernstudiengang basiert auf Entwicklungen zur Lehrerausbildung im Bereich neuer Medien, wie sie im Rahmen der Initiative „Bildungswege in der Informationsgesellschaft (BIG“ erarbeitet wurden (vgl. u.a. Tulodziecki/Moll/Gallasch 2001. Die – 1995 begonnene – BIG-Initiative geht auf die Bertelsmann Stiftung und Heinz Nixdorf Stiftung zurück. Die jetzige Projektarbeit wird von der ,,e-nitiative.nrw.Netzwerk für Bildung“ gefördert.

Wäre es Dir lieber, ich würde zu Recht verurteilt? - Sokrates Bund und die Frage der Kontrolle

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Katharina Kaiser-Müller

2014-09-01

Full Text Available Die Ablösung von zweifelhafter menschlicher Kontrolle durch eine zuverlässige Software bietet eindrucksvolle Möglichkeiten. Mit der flächendeckenden Einführung von Sokrates Bund zum Schuljahr 2014/2015 wird endlich die Identifzierung von Pisadurchschnittsverderbern möglich. Die AutorInnen diskutieren die Lage ... Die Situation war dramatisch: Ungerecht angeklagt wegen Verführung der Jugend und Gottlosigkeit, sieht Sokrates dem Tod durch den Schierlingsbecher entgegen und antwortet auf die ob des Fehlurteils durchaus verständliche Klage von Xanthippe mit der titelgebenden Frage. Anschließend verweigert er die Flucht und zieht es vor, sich dem formal korrekt gefällten falschen Urteil zu beugen. Eine legendäre Entscheidung, in der Sokrates die Gesetzestreue mit der Begründung, man müsse schlechte Gesetze ändern, dürfe sie aber nicht übertreten, über das eigene Wohl stellt.

Present evaluation of the use of rape oil/RME compared to diesel fuel. Appendix 1: Resources and emission balances: rape oil and RME compared to diesel fuel. Appendix 2: Economic evaluation of the use of rape oil and RME compared to diesel fuel; Aktuelle Bewertung des Einsatzes von Rapsoel/RME im Vergleich zu Dieselkraftstoff. Anhang 1: Ressourcen- und Emissionsbilanzen: Rapsoel und RME im Vergleich zu Dieselkraftstoff. Anhang 2: Oekonomische Bewertung des Einsatzes von Rapsoel und RME gegenueber Dieselkraftstoff

Energy Technology Data Exchange (ETDEWEB)

Kraus, K.; Niklas, G.; Tappe, M.; Reinhardt, G.A. [ifeu-Institut fuer Energie- und Umweltforschung GmbH, Heidelberg (Germany); Folkers, C. [Bochum Univ. (Germany). Lehrstuhl fuer Finanzwissenschaft

1999-12-01

New recognitions in the sectors of research, development in the processing industry, motor vehicle technology, ecological balance methodics, the high interest in environmental policy and some other points of criticism have motivated the Umweltbundesamt to update the corresponding parts of the '1993 eco-balance rape oil'. Balancing of the particularly critically discussed sectors of resource consumption and airborne environmental impacts over the entire life cycle of rape oil based fuels as compared to diesel fuel was taken care of by the ifeu Institute. That balances were only made up for these two sectors is due to the fact that it is here where the particular environmental advantages of vegetable fuel oils are supposedly brought to bear. Moreover, on the basis of the report 'renewable energy sources - fundamentals, methods, ecological balancing' published recently and sponsored by the Deutsche Bundesstiftung Umwelt, topical essential factors such as the redefinition of the reference system (short-rotation cultivation instead of permanent fallowness) could be taken into account by the expertise. A particular benefit attributed to rape oil and RME is the conservation of fossil energy sources and associated abatement of the greenhouse effect (especially carbon dioxide). Cutting down greenhouse gas emissions is one of the predominant aims of national and international environmental policy with a view to preventing a dangerous man-made disturbance of climate. (orig.) [German] Neue Erkenntnisse im Bereich der Forschung, der Entwicklungen der verarbeitenden Industrie, der Fahrzeugtechnik, der Oekobilanzmethodik, das hohe umweltpolitische Interesse sowie die zuvor genannten Kritikpunkte haben das Umweltbundesamt veranlasst, die entsprechenden Teile der 'Oekobilanz Rapsoel' von 1993 auf den neuesten Stand zu bringen. Das ifeu-Institut hat die besonders kritisch diskutierten Bereiche des Ressourcenverbrauchs und der luftgetragenen

Medienbildung als konstruktive Aneignung von Medienensembles. Vorbemerkungen zu einer Theorie der Medienpädagogik

Directory of Open Access Journals (Sweden)

Tilman Bechthold-Hengelhaupt

2016-12-01

Full Text Available Die These dieses Aufsatzes lautet, dass im medienpädagogischen Handeln und Kommunizieren Erfahrungen mit dinglich gegebenen Medien verarbeitet und dass dadurch Medienensembles konstruiert werden, also praktisch verfügbare Konfigurationen von Geräten und Gegenständen, unter denen die beteiligten Akteure eine Auswahl treffen können. Der Begriff der Wahl lässt insbesondere einen Anschluss an die Idee einer demokratischen Medienbildung zu. Als erkenntnistheoretische Grundlage wird eine Orientierung an der sinnlichen Erfahrung vorgeschlagen, die gerade in Immanuel Kants "Kritik der reinen Vernunft" als Erkenntnisquelle begründet wird. Dass der Begriff der Medienensembles auch die historische Dimension aufschließen kann, wird am Beispiel des so genannten Neumagener Schulreliefs gezeigt, einem archäologischen Dokument aus der Zeit um 180 n.Chr. This essay proposes the thesis that media education should be understood as consisting in negotiations about experiences with media ensembles. In a constructivist approach, the acting with media ensembles is seen as a form of coming to terms with devices and other media objects that are accessible via sensory experience. In this context, a pivotal idea is that choices are made between different media that are at hand for educational purposes. This concept is further elaborated in the concepts of Immanuel Kant's theory of perception. As an example, an archaeological monument from ca. 180 AD ("Neumagener Schulrelief" is described and interpreted.

[High-performance liquid-liquid chromatography in beverage analysis].

Science.gov (United States)

Bricout, J; Koziet, Y; de Carpentrie, B

1978-01-01

Liquid liquid chromatography was performed with columns packed with stationary phases chemically bonded to silica microparticules. These columns show a high efficiency and are used very easily. Flavouring compounds like aromatic aldehydes which have a low volatility were analyzed in brandy using a polar phase alkylnitrile. Sapid substances like amarogentin in Gentiana lutea or glyryrrhizin in Glycyrrhiza glabra were determined by reversed phase chromatography. Finally ionizable substances like synthetic dyes can be analyzed by paired ion chromatography witha non polar stationary phase.

Prostate cell membrane chromatography-liquid chromatography-mass spectrometry for screening of active constituents from Uncaria rhynchophylla.

Science.gov (United States)

He, Jianyu; Han, Shengli; Yang, Fangfang; Zhou, Nan; Wang, Sicen

2013-01-01

Uncaria rhynchophylla is a traditional Chinese medicinal herb used to treat hypertension and convulsive disorders such as epilepsy. Rat prostate cell membrane chromatography combined with liquid chromatography-mass spectrometry (LC-MS) was used to identify active constituents from U. rhynchophylla extracts. Four compounds (corynoxeine, isorhynchophylline, isocorynoxeine and rhynchophylline) were discovered. Competitive binding assay results indicated that the four compounds were in direct competition at a single common binding site and interacted with α1A adrenergic receptors (α1A-AR) in a manner similar to tamsulosin. Affinity constant values of the four compounds binding with α1A-AR were also measured using rat prostate cell membrane chromatography (CMC). Finally, their pharmacodynamic effects were tested on rat caudal arteries. This CMC combined LC-MS system offers a means of drug discovery by screening natural medicinal herbs for new pharmacologically active molecules targeting specific receptors.

performance liquid chromatography

African Journals Online (AJOL)

user

2010-11-22

Nov 22, 2010 ... ISSN 1684–5315 © 2010 Academic Journals. Full Length Research Paper. Determination ... Key words: Processed food, high-performance liquid chromatography, acrylamide, health hazard. INTRODUCTION. In the year 2002, the ... potatoes, breakfast cereals etc. It was thus confirmed that acrylamide has ...

Development of a high performance liquid chromatography method ...

African Journals Online (AJOL)

Development of a high performance liquid chromatography method for simultaneous ... Purpose: To develop and validate a new low-cost high performance liquid chromatography (HPLC) method for ..... Several papers have reported the use of ...

Laboratory and field based evaluation of chromatography ...

Science.gov (United States)

The Monitor for AeRosols and GAses in ambient air (MARGA) is an on-line ion-chromatography-based instrument designed for speciation of the inorganic gas and aerosol ammonium-nitrate-sulfate system. Previous work to characterize the performance of the MARGA has been primarily based on field comparison to other measurement methods to evaluate accuracy. While such studies are useful, the underlying reasons for disagreement among methods are not always clear. This study examines aspects of MARGA accuracy and precision specifically related to automated chromatography analysis. Using laboratory standards, analytical accuracy, precision, and method detection limits derived from the MARGA chromatography software are compared to an alternative software package (Chromeleon, Thermo Scientific Dionex). Field measurements are used to further evaluate instrument performance, including the MARGA’s use of an internal LiBr standard to control accuracy. Using gas/aerosol ratios and aerosol neutralization state as a case study, the impact of chromatography on measurement error is assessed. The new generation of on-line chromatography-based gas and particle measurement systems have many advantages, including simultaneous analysis of multiple pollutants. The Monitor for Aerosols and Gases in Ambient Air (MARGA) is such an instrument that is used in North America, Europe, and Asia for atmospheric process studies as well as routine monitoring. While the instrument has been evaluat

Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses

OpenAIRE

Suriyavathana Muthukrishnan; Subha Palanisamy; Senthilkumar Subramanian; Sumathi Selvaraj; Kavitha Rani Mari; Ramalingam Kuppulingam

2016-01-01

Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. Th...

Electron-capture process and ion mobility spectra in plasma chromatography

International Nuclear Information System (INIS)

Karasek, F.W.; Spangler, G.E.

1981-01-01

The basic principles of plasma chromatography are introduced and ion mobility relationships presented. The relationships of plasma chromatography to electron-capture detector mechanisms are discussed, including electron energy considerations and electron-capture reactions. A number of experimental studies by plasma chromatography are described. (C.F.)

Chromatography in Industry

Science.gov (United States)

Schoenmakers, Peter

2009-07-01

This review focuses on the chromatography research that has been carried out within industry or in close cooperation with industry and that has been reported in the scientific literature between 2006 and mid-2008. Companies in the health care sector, such as pharmaceutical and biotechnology companies, are the largest contributors. Industrial research seems to take place in an open environment in cooperation with academia, peer companies, and institutions. Industry appears ready to embrace new technologies as they emerge, but they focus strongly on making chromatography work robustly, reliably, rapidly, and automatically. “Hyphenated” systems that incorporate on-line sample-preparation techniques and mass-spectrometric detection are the rule rather than the exception. Various multidimensional separation methods are finding numerous applications. Strategies aimed at speeding up the development of new chromatographic methods remain the focus of attention. Also, there is a clear trend toward exploring chromatographic methods for parallel processing along with other strategies for high-throughput analysis.

Separation of Chloroplast Pigments Using Reverse Phase Chromatography.

Science.gov (United States)

Reese, R. Neil

1997-01-01

Presents a protocol that uses reverse phase chromatography for the separation of chloroplast pigments. Provides a simple and relatively safe procedure for use in teaching laboratories. Discusses pigment extraction, chromatography, results, and advantages of the process. (JRH)

Thin-layer chromatography - liquid chromatography, an ideal supplement demonstrated by the separation of lanthanoids

International Nuclear Information System (INIS)

Specker, H.; Hufnagel, A.

1984-01-01

All lanthanoids have been separated by thin-layer chromatography (TLC) with short retention times by using a mixture of ether/tetrahydrofurane (THF)/bis-(2-ethylhexyl)-phosphate (HDEHP)/nitric acid. The eluent was empirically tested by synergistic effects. The results have been transferred to high-performance liquid chromatography /HPLC). It was possible to use the same eluent in TLC and HPLC both for the analytical separation of all lanthanoids and for the separation of fission products. The experimental experience gained in HPLC could be applied to the pre-concentration of isotopes in TLC. Both methods excellently supplemented each other in the separation of lanthanoids. (orig.) [de

Advances in chromatography of the rare earth elements (review)

International Nuclear Information System (INIS)

Oguma, Koichi; Kuroda, Rokuro; Shimizu, Tsuneo.

1995-01-01

A review is presented which covers liquid chromatography, gas chromatography, and related techniques. This article intends to describe the chromatographic methods playing an important role in the separation of the rare earth elements. Special attention is paid to the usefulness of various types of liquid chromatography which enable the complete mutual separation of the rare earth elements. Applications are also discussed. (author) 161 refs

5-O-caffeoylshikimic acid from Solanum somalense leaves: advantage of centrifugal partition chromatography over conventional column chromatography.

Science.gov (United States)

Chideh, Saïda; Pilard, Serge; Attoumbré, Jacques; Saguez, Robert; Hassan-Abdallah, Alshaimaa; Cailleu, Dominique; Wadouachi, Anne; Baltora-Rosset, Sylvie

2014-09-01

Solanum somalense leaves, used in Djibouti for their medicinal properties, were extracted by MeOH. Because of the high polyphenol and flavonoid contents of the extract, respectively, determined at 80.80 ± 2.13 mg gallic acid equivalent/g dry weight and 24.4 ± 1.01 mg quercetin equivalent/g dry weight, the isolation and purification of the main polyphenols were carried out by silica gel column chromatography and centrifugal partition chromatography. Column chromatography led to 11 enriched fractions requiring further purification, while centrifugal partition chromatography allowed the easy recovery of the main compound of the extract. In a solvent system composed of CHCl3/MeOH/H2O (9.5:10:5), 21.8 mg of this compound at 97% purity was obtained leading to a yield of 2.63%. Its structure was established as 5-O-caffeoylshikimic acid by mass spectrometry and NMR spectroscopy. This work shows that S. somalense leaves contain very high level of 5-O-caffeoylshikimic acid (0.74% dry weight), making it a potential source of production of this secondary metabolite that is not commonly found in nature but could be partly responsible of the medicinal properties of S. somalense leaves. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid-adsorption chromatography of metal 8-hydroxyquinolinates

International Nuclear Information System (INIS)

Basova, E.M.; Bol'shova, T.A.; Shirshova, T.S.

1988-01-01

Using the method of liquid-adsorption chromatography separation of 8-hydroxyquinolinates of Cu, Fe, Ga, In, Al, Ni is realized. Thin-layer chromatography (TLC) is used to define the optimum conditions of separation and highly efficient liquid column chromatography (HELC) - for chelate separation. Applicaton of the same sorbent is a very important condition of transition from TLC to HELC. Solica gel Partisil, mobile phase: benzene - isopropanol mixture, containing 1 x 10 -3 M of 8-hydroxyquinoline, are the optimal conditions for the studied chelates separation. But In and Ga in TLC move together, and in HELC they are partially separated, therefore, for their separation the column selectivity should be improved by selection of mobile phase

[Column chromatography purification and analysis of biodiesel by transesterification].

Science.gov (United States)

Liu, Yang; Yi, Huai-feng; Chen, Yu; Wu, Yu-long; Yang, Ming-de; Chen, Zeng; Tong, Jun-mao

2012-02-01

In the present paper, crude biodiesel prepared with sorbifolia oil as raw material by transesterification was purified by column chromatography, then the composition of biodiesel was analyzed by gas chromatography, FTIR, GC-MS and 1H NMR. Column chromatography can separate the crude biodiesel into two fractions: petroleum ether eluted fraction (A1) and methanol eluted fraction (A2). Petroleum ether eluted fraction was mainly biodiesel fraction, which was produced from sorbifolia oil by transesterification, including methyl linoleate, methyl cis-9-octadecenoate and so on; methanol eluted fraction was mainly glycerol fraction, which came from the side reaction of transesterification. The results show that the purity of refined biodiesel increased from 77.51% to 93.872, and the product recovery rate reached up to 91.04% after the purification by column chromatography. The results obtained by FTIR and 1H NMR further showed that the column chromatography can effectively improve the purity of biodiesel. This paper provides a basis for industrialization of purification of biodiesel.

High perfomance liquid chromatography in pharmaceutical analyses.

Science.gov (United States)

Nikolin, Branko; Imamović, Belma; Medanhodzić-Vuk, Saira; Sober, Miroslav

2004-05-01

In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatography replaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography (HPLC) analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1) Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or serum contains numerous endogenous

Ökonomie der Bandbreite: Evolutionär-ökonomische und kulturanthropologische Überlegungen zu Schnittstellen in Mensch-Maschine-Komplexen

Directory of Open Access Journals (Sweden)

Manuel Wäckerle

2012-09-01

Full Text Available In diesem Artikel diskutieren wir Bandbreite als kognitive, kulturelle und technische Regel, als eine Regel, die Informationsübertragung pro Zeiteinheit beschränkt. Wir verstehen Wirtschaft, Kultur und Gesellschaft als regelbasiertes evolvierendes System und geben der Bandbreite als generische Regel eine zentrale Rolle. Dabei untersuchen wir theoretisch die wechselwirkenden Prozesse der Ausbeutung und Ausweitung von Bandbreite in Mensch-Maschine-Komplexen. Des Weiteren verweisen wir auf die historische Dimension der digitalisierten Gesellschaft und diskutieren kulturelle Entwicklungen von evolvierten Prothesen. In diesem Zusammenhang formulieren wir eine Genealogie von Gleichheit und Freiheit im Netz. Abschließend betrachten wir zwei Beispiele von evolvierenden Prothesen: Das „Automated Trading“ und die Thematik des „Freundschaftskapitals bei Facebook“. Es zeigt sich, dass sich in beiden Beispielen, so unterschiedlich ihre Implikationen auf ersten Blick auch sind, systemisches Risiko auf ähnliche Art und Weise akkumuliert. Unser Artikel versucht einerseits wesentliche Aspekte der Ökonomie der Bandbreite aufzuzeigen, andererseits erste interdisziplinäre Denkschemata für ebendiese zu entwickeln.

Osteoblast cell membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry for screening specific active components from traditional Chinese medicines.

Science.gov (United States)

Wang, Nani; Zhang, Qiaoyan; Xin, Hailiang; Shou, Dan; Qin, Luping

2017-11-01

A method using osteoblast membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry was developed to recognize and identify the specific active components from traditional Chinese medicines. Primary rat osteoblasts were used for the preparation of the stationary phase in the cell chromatography method. Retention components from the cell chromatography were collected and analyzed by liquid chromatography with time-of-flight mass spectrometry. This method was applied in screening active components from extracts of four traditional Chinese medicines. In total, 24 potentially active components with different structures were retained by osteoblast cell chromatography. There were five phenolic glucosides and one triterpenoid saponin from Curculigo orchioides Gaertn, two organic acids and ten flavonoids from Epimedium sagittatum Maxim, one phthalide compound and one organic acid from Angelica sinensis Diels, and two flavonoids and two saponins from Anemarrhena asphodeloides Bunge. Among those, four components (icariin, curculigoside, ferulaic acid, and timosaponin BII) were used for in vitro pharmacodynamics validation. They significantly increased the osteoblast proliferation, alkaline phosphatase activity, levels of bone gla protein and collagen type 1, and promoted mineralized nodule formation. The developed method was an effective screening method for finding active components from complex medicines that act on bone diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pseudo-affinity chromatography of rumen microbial cellulase on ...

African Journals Online (AJOL)

Pseudo-affinity chromatography of rumen microbial cellulase on Sepharose- Cibacron Blue F3GA. ... African Journal of Biotechnology ... Pseudo affinity adsorption of bioproducts on Sepharose-cibacron blue F3-GA was subjected to rumen microbial enzyme evaluation through batch binding and column chromatography of ...

Purification of a synthetic pterocarpanquinone by countercurrent chromatography

International Nuclear Information System (INIS)

Costa, Fernanda das Neves; Silva, Alcides Jose M. da; Domingos, Jorge L. de Oliveira; Costa, Paulo Roberto R.; Leitao, Gilda G.; Daher Netto, Chaquip

2012-01-01

Countercurrent chromatography (CCC) was employed as a useful, fast and economic alternative to conventional chromatography techniques for the purification of a synthetic pterocarpanquinone, LQB-118. The separation was performed in a two-step CCC with the solvent system hexanechloroform- methanol-water 2:1.5:5:2 in both steps. Traditional purification of these reaction products by silica gel column chromatography demanded a large amount of solvent and time, besides allowing the irreversible adsorption of the compound in the column. The use of 1 H NMR for the calculation of KD of target compound is proposed as an alternative for HPLC measurements. (author)

Gas chromatography at the Tritium Laboratory Karlsruhe

International Nuclear Information System (INIS)

Laesser, R.; Gruenhagen, S.

2003-08-01

Among the analytical techniques (mass spectrometry, laser Raman spectroscopy, gas chromatography, use of ionisation chambers) employed at the Tritium Laboratory Karlsruhe (TLK), gas chromatography plays a prominent role. The main reasons for that are the simplicity of the gas chromatographic separation process, the small space required for the equipment, the low investment costs in comparison to other methods, the robustness of the equipment, the simple and straightforward analysis and the fact that all gas species of interest (with the exception of water) can easily be detected by gas chromatographic means. The conventional gas chromatographs GC1 and GC2 used in the Tritium Measurement Techniques (TMT) System of the TLK and the gas chromatograph GC3 of the experiment CAPER are presented in detail, by discussing their flow diagrams, their major components, the chromatograms measured by means of various detectors, shortcomings and possible improvements. One of the main disadvantages of the conventional gas chromatography is the long retention times required for the analysis of hydrogen gas mixtures. To overcome this disadvantage, micro gas chromatography for hydrogen analysis was developed. Reduction of the retention times by one order of magnitude was achieved. (orig.)

High performance liquid chromatography in pharmaceutical analyses

Directory of Open Access Journals (Sweden)

Branko Nikolin

2004-05-01

Full Text Available In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatographyreplaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography(HPLC analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1 Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or

„Wir verbrachten mehr als 24 Stunden, ohne etwas anderes als Schokolade und Limonade zu uns zu nehmen“. Hinweise in Alexander von Humboldts Tagebuchaufzeichnungen zu Fragen der Verpflegung auf der Forschungsreise durch Spanisch-Amerika

Directory of Open Access Journals (Sweden)

Ursula Thiemer-Sachse

2013-12-01

Full Text Available Zusammenfassung In Alexander von Humboldts Tagebüchern seiner berühmten Forschungsreise durch Spanisch-Amerika finden sich Bemerkungen und Hinweise für künftige Leser seiner Reisedarstellungen zu Problemen der Verpflegung. Zumeist werden Engpässe und Missstände erwähnt sowie Fragen soziopolitischer Situation verdeutlicht. Sie beziehen sich auf Extrembedingungen in stadtfernen Gebieten und im Kontakt mit den indigenen Trägern und Helfern während der einzelnen Exkursionen. Die Darstellungen der alltäglichen Gegebenheiten sind zugleich eine interessante Quelle für Verhaltensmuster der verschiedenen Schichten der spanischkolonialen Gesellschaft wie der Forschungsreisenden, die mit den Schwierigkeiten umzugehen hatten, sich anzupassen verstanden oder ihre eigenen Verhaltensmuster entwickelt haben. Damit ermöglichen Humboldts Aufzeichnungen zugleich auch auf diesem Gebiet manchen Blick auf den seither erfolgten Kulturwandel. Resumen En los diarios del famoso viaje de estudios de Alejandro de Humboldt por la América española se encuentran observaciones y notas sobre problemas de aprovisionamiento, en favor de lectores futuros de sus relaciones de viaje. En la mayoría de los casos Humboldt menciona situaciones precarias o ilustra cuestiones de carácter sociopolítico. Frecuentemente, sus apuntes se refieren a condiciones extremas en regiones remotas y en contacto con los cargadores y ayudantes indígenas durante las diferentes excursiones. Las descripciones de los acontecimientos cotidianos al mismo tiempo son una fuente interesante sobre los modos de proceder de las diferentes capas de la sociedad colonial española así como de los viajeros científicos que tuvieron que enfrentar dificultades a las cuales había que adaptarse o desarrollar modelos propios de comportamiento. Por esto al mismo tiempo las noticias de Humboldt también en este asunto posibilitan más de una vez la atención al cambio cultural que se ha realizado hasta hoy

Detection of radiation-induced hydrocarbons in Camembert irradiated before and after the maturing process-comparison of florisil column chromatography and on-line coupled liquid chromatography-gas chromatography

International Nuclear Information System (INIS)

Schulzki, G.; Spiegelberg, A.; Bögl, K.W.; Schreiber, G.A.

1995-01-01

The influence of the maturing process on the detection of radiation-induced volatile hydrocarbons in the fat of Camembert has been investigated. Two analytical methods for separation of the hydrocarbon fraction from the lipid were applied: Florisil column chromatography with subsequent gas chromatographic-mass spectrometric (GC-MS) determination as well as on-line coupled liquid chromatography-GC-MS. The maturing process had no influence on the detection of radiation-induced volatiles. Comparable results were achieved with both analytical methods. However, preference is given to the more effective on-line coupled LC-GC method

Recent applications of gas chromatography with high-resolution mass spectrometry.

Science.gov (United States)

Špánik, Ivan; Machyňáková, Andrea

2018-01-01

Gas chromatography coupled to high-resolution mass spectrometry is a powerful analytical method that combines excellent separation power of gas chromatography with improved identification based on an accurate mass measurement. These features designate gas chromatography with high-resolution mass spectrometry as the first choice for identification and structure elucidation of unknown volatile and semi-volatile organic compounds. Gas chromatography with high-resolution mass spectrometry quantitative analyses was previously focused on the determination of dioxins and related compounds using magnetic sector type analyzers, a standing requirement of many international standards. The introduction of a quadrupole high-resolution time-of-flight mass analyzer broadened interest in this method and novel applications were developed, especially for multi-target screening purposes. This review is focused on the development and the most interesting applications of gas chromatography coupled to high-resolution mass spectrometry towards analysis of environmental matrices, biological fluids, and food safety since 2010. The main attention is paid to various approaches and applications of gas chromatography coupled to high-resolution mass spectrometry for non-target screening to identify contaminants and to characterize the chemical composition of environmental, food, and biological samples. The most interesting quantitative applications, where a significant contribution of gas chromatography with high-resolution mass spectrometry over the currently used methods is expected, will be discussed as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radial Chromatography for the Separation of Nitroaniline Isomers

Science.gov (United States)

Miller, Robert B.; Case, William S.

2011-01-01

Separation techniques are usually presented in the undergraduate organic laboratory to teach students how to purify and isolate compounds. Often the concept of liquid chromatography is introduced by having students create "silica gel columns" to separate components of a reaction mixture. Although useful, column chromatography can be a laborious…

Technological options in regard to reducing harmful environmental effects of road traffic. Fuel cell technology compared with combustion engines; Technische Optionen zur Verminderung der Verkehrsbelastungen. Brennstoffzellenfahrzeuge im Vergleich zu Fahrzeugen mit Verbrennungsmotoren

Energy Technology Data Exchange (ETDEWEB)

Kolke, R. [comp.

1999-05-01

The German Umweltbundesamt (federal environmental agency) commissioned a cost-benefit analysis to be made, testing the practical performance of fuel cell-driven automobiles, for state-of-the-art assessment of their benefits and drawbacks as compared to other available automotive fuel systems. Results available so far of calculations based on the cost-benefit analysis show that the targets involved, such as cutback of emissions and conservation of resources, can be realised within the foreseeable future at much lesser expense through the use of fuel consumption-optimized Otto engines offering lowest emission levels (of the type ULEV, ultra-low emission vehicle, or EURO 4 standard), as compared to the relevant contributions to emission reduction and other targets offered by the fuel cell-driven automobiles.(orig./CB) [Deutsch] Das Umweltbundesamt hat die Brennstoffzellentechnik im Verkehr einer Kosten-Nutzen-Betrachtung unterzogen, um zu ermitteln, welche Vor- und Nachteile sie im Vergleich zu anderen Antriebskonzepten im Verkehr nach derzeitigem Wissensstand hat. Nach den bisherigen Berechnungen am Beispiel einer Kosten-Nutzen-Analyse zeichnet sich ab, dass Emissionsminderungen und Ressourcenschutz fuer die absehbare Zeit wesentlich kostenguenstiger durch verbrauchsoptimierte Fahrzeuge mit Ottomotor mit niedrigsten Abgasemissionen (ULEV-`Ultra Low Emission Vehicle` oder EURO 4-Standard) realisiert werden koennen als durch Fahrzeuge mit Brennstoffzellenantrieb. (orig.)

Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography.

Science.gov (United States)

Vu, Anh T; Wang, Xinying; Wickramasinghe, S Ranil; Yu, Bing; Yuan, Hua; Cong, Hailin; Luo, Yongli; Tang, Jianguo

2015-08-01

Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

UHPLC: The Greening Face of Liquid Chromatography

OpenAIRE

Cielecka-Piontek, Judyta; Zalewski, Przemys?aw; Jeli?ska, Anna; Garbacki, Piotr

2013-01-01

Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) h...

Selection of imprinted nanoparticles by affinity chromatography.

Science.gov (United States)

Guerreiro, António R; Chianella, Iva; Piletska, Elena; Whitcombe, Michael J; Piletsky, Sergey A

2009-04-15

Soluble molecularly imprinted nanoparticles were synthesised via iniferter initiated polymerisation and separated by size via gel permeation chromatography. Subsequent fractionation of these particles by affinity chromatography allowed the separation of high affinity fractions from the mixture of nanoparticles. Fractions selected this way possess affinity similar to that of natural antibodies (K(d) 6.6x10(-8)) M and were also able to discriminate between related functional analogues of the template.

Normal and Reversed-Phase Thin Layer Chromatography of Green Leaf Extracts

Science.gov (United States)

Sjursnes, Birte Johanne; Kvittingen, Lise; Schmid, Rudolf

2015-01-01

Introductory experiments of chromatography are often conducted by separating colored samples, such as inks, dyes, and plant extracts, using filter paper, chalk, or thin layer chromatography (TLC) plates with various solvent systems. Many simple experiments have been reported. The relationship between normal chromatography and reversed-phase…

Diagonal chromatography to study plant protein modifications.

Science.gov (United States)

Walton, Alan; Tsiatsiani, Liana; Jacques, Silke; Stes, Elisabeth; Messens, Joris; Van Breusegem, Frank; Goormachtig, Sofie; Gevaert, Kris

2016-08-01

An interesting asset of diagonal chromatography, which we have introduced for contemporary proteome research, is its high versatility concerning proteomic applications. Indeed, the peptide modification or sorting step that is required between consecutive peptide separations can easily be altered and thereby allows for the enrichment of specific, though different types of peptides. Here, we focus on the application of diagonal chromatography for the study of modifications of plant proteins. In particular, we show how diagonal chromatography allows for studying proteins processed by proteases, protein ubiquitination, and the oxidation of protein-bound methionines. We discuss the actual sorting steps needed for each of these applications and the obtained results. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock. Copyright © 2016 Elsevier B.V. All rights reserved.

Ion-Exchange Chromatography: Basic Principles and Application.

Science.gov (United States)

Cummins, Philip M; Rochfort, Keith D; O'Connor, Brendan F

2017-01-01

Ion-Exchange Chromatography (IEC) allows for the separation of ionizable molecules on the basis of differences in charge properties. Its large sample-handling capacity, broad applicability (particularly to proteins and enzymes), moderate cost, powerful resolving ability, and ease of scale-up and automation have led to it becoming one of the most versatile and widely used of all liquid chromatography (LC) techniques. In this chapter, we review the basic principles of IEC, as well as the broader criteria for selecting IEC conditions. By way of further illustration, we outline basic laboratory protocols to partially purify a soluble serine peptidase from bovine whole brain tissue, covering crude tissue extract preparation through to partial purification of the target enzyme using anion-exchange chromatography. Protocols for assaying total protein and enzyme activity in both pre- and post-IEC fractions are also described.

Liquid chromatography detection unit, system, and method

Science.gov (United States)

Derenzo, Stephen E.; Moses, William W.

2015-10-27

An embodiment of a liquid chromatography detection unit includes a fluid channel and a radiation detector. The radiation detector is operable to image a distribution of a radiolabeled compound as the distribution travels along the fluid channel. An embodiment of a liquid chromatography system includes an injector, a separation column, and a radiation detector. The injector is operable to inject a sample that includes a radiolabeled compound into a solvent stream. The position sensitive radiation detector is operable to image a distribution of the radiolabeled compound as the distribution travels along a fluid channel. An embodiment of a method of liquid chromatography includes injecting a sample that comprises radiolabeled compounds into a solvent. The radiolabeled compounds are then separated. A position sensitive radiation detector is employed to image distributions of the radiolabeled compounds as the radiolabeled compounds travel along a fluid channel.

Electrochemical Detectors in HPLC and Ion Chromatography.

Science.gov (United States)

Horvai, George; Pungor, ErnÕ

1989-01-01

Back in 1952, the renowned Polish electrochemist Wiktor Kemula introduced chromato-polarography, 1 i.e., polaro-graphic detection for liquid chromatography. This technique continued to develop slowly until the early 1970s (for a review see Reference 2) when modem high-performance liquid chromatography (HPLC) emerged. This new, highly efficient chromatographc method could only be. used with detectors ensuring low dispersion. It was not easy to modify the dropping mercury electrode cells to satisfy this requirement. However, at the same time, electroanalytical chemists, who already had much experience in using carbon-based electrodes for oxidative detection in flow analysis, put forward the idea of oxidative amperometric detection in liquid chromatography. 3,4 In this technique, solid or quasi-solid (paste) electrodes were used and this made possible the construction of miniaturized cells with just a few microliter volume.

Introduction to modern liquid chromatography

National Research Council Canada - National Science Library

Snyder, Lloyd R; Kirkland, J. J; Dolan, John W

2010-01-01

"High-performance liquid chromatography (HPLC) is today the leading technique for chemical analysis and related applications, with an ability to separate, analyze, and/or purify virtually any sample...

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

2015-01-01

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

2015-01-01

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

2015-01-01

Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

Design of preparative-supercritical fluid chromatography.

Science.gov (United States)

Rajendran, Arvind

2012-08-10

Preparative supercritical fluid chromatography (prep-SFC) is an important separation process in the chromatographers toolbox. Owing to the unique properties of the mobile phase, which is predominantly CO(2), the behavior of SFC is markedly different from high performance liquid chromatography (HPLC). This review article focuses on the scale-up of preparative chromatography. The basics of SFC, with particular focus on highlighting the key differences between SFC and HPLC, are introduced. Then, a framework for rational design of prep-SFC is proposed. This framework is based on obtaining basic system parameters from analytical scale equipment, i.e., with very small amount of material, and performing design and optimization in silico to evaluate process performance and to identify operating conditions for scale-up. The tools required to obtain the input parameters such as adsorption isotherms are discussed and the development of the design and optimization framework is elaborated. Examples from the literature which use this approach for successful scale-up are provided. Finally the design of multi-column SFC systems is discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Affinity monolith chromatography: A review of general principles and applications.

Science.gov (United States)

Li, Zhao; Rodriguez, Elliott; Azaria, Shiden; Pekarek, Allegra; Hage, David S

2017-11-01

Affinity monolith chromatography, or AMC, is a liquid chromatographic method in which the support is a monolith and the stationary phase is a biological-binding agent or related mimic. AMC has become popular for the isolation of biochemicals, for the measurement of various analytes, and for studying biological interactions. This review will examine the principles and applications of AMC. The materials that have been used to prepare AMC columns will be discussed, which have included various organic polymers, silica, agarose, and cryogels. Immobilization schemes that have been used in AMC will also be considered. Various binding agents and applications that have been reported for AMC will then be described. These applications will include the use of AMC for bioaffinity chromatography, immunoaffinity chromatography, dye-ligand affinity chromatography, and immobilized metal-ion affinity chromatography. The use of AMC with chiral stationary phases and as a tool to characterize biological interactions will also be examined. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two-Dimensional Liquid Chromatography Analysis of Polystyrene/Polybutadiene Block Copolymers.

Science.gov (United States)

Lee, Sanghoon; Choi, Heejae; Chang, Taihyun; Staal, Bastiaan

2018-05-15

A detailed characterization of a commercial polystyrene/polybutadiene block copolymer material (Styrolux) was carried out using two-dimensional liquid chromatography (2D-LC). The Styrolux is prepared by statistical linking reaction of two different polystyrene- block-polybutadienyl anion precursors with a multivalent linking agent. Therefore, it is a mixture of a number of branched block copolymers different in molecular weight, composition, and chain architecture. While individual LC analysis, including size exclusion chromatography, interaction chromatography, or liquid chromatography at critical condition, is not good enough to resolve all the polymer species, 2D-LC separations coupling two chromatography methods were able to resolve all polymer species present in the sample; at least 13 block copolymer species and a homopolystyrene blended. Four different 2D-LC analyses combining a different pair of two LC methods provide their characteristic separation results. The separation characteristics of the 2D-LC separations are compared to elucidate the elution characteristics of the block copolymer species.

Column Chromatography To Obtain Organic Cation Sorption Isotherms.

Science.gov (United States)

Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

2016-08-02

Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

Supercritical fluid chromatography for lipid analysis in foodstuffs.

Science.gov (United States)

Donato, Paola; Inferrera, Veronica; Sciarrone, Danilo; Mondello, Luigi

2017-01-01

The task of lipid analysis has always challenged separation scientists, and new techniques in chromatography were often developed for the separation of lipids; however, no single technique or methodology is yet capable of affording a comprehensive screening of all lipid species and classes. This review acquaints the role of supercritical fluid chromatography within the field of lipid analysis, from the early developed capillary separations based on pure CO 2 , to the most recent techniques employing packed columns under subcritical conditions, including the niche multidimensional techniques using supercritical fluids in at least one of the separation dimensions. A short history of supercritical fluid chromatography will be introduced first, from its early popularity in the late 1980s, to the sudden fall and oblivion until the last decade, experiencing a regain of interest within the chromatographic community. Afterwards, the subject of lipid nomenclature and classification will be briefly dealt with, before discussing the main applications of supercritical fluid chromatography for food analysis, according to the specific class of lipids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contribution to high-temperature chromatography and high-temperature-gas-chromatography-mass spectrometry of lipids

International Nuclear Information System (INIS)

Aichholz, R.

1998-04-01

This thesis describes the use of high temperature gas chromatography for the investigation of unusual triacylglycerols, cyanolipids and bees waxes. The used glass capillary columns were pretreated and coated with tailor made synthesized high temperature stable polysiloxane phases. The selective separation properties of the individual columns were tested with a synthetic lipid mixture. Suitable derivatization procedures for the gaschromatographic analyses of neutral lipids, containing multiple bonds as well as hydroxy-, epoxy-, and carboxyl groups, were developed and optimized. Therefore conjugated olefinic-, conjugated olefinic-acetylenic-, hydroxy-, epoxy-, and conjugated olefinic keto triacylglycerols in miscellaneous plant seed oils as well as hydroxy monoesters, diesters and hydroxy diesters in bees waxes could be analysed directly with high temperature gas chromatography for the first time. In order to elucidate the structures of separated lipid compounds, high temperature gas chromatography was coupled to mass spectrometry and tandem mass spectrometry, respectively. Comparable analytical systems are hitherto not commercial available. Therefore instrumental prerequisites for a comprehensive and detailed analysis of seed oils and bees waxes were established. In GC/MS commonly two ionization methods are used, electron impact ionization and chemical ionization. For the analysis of lipids the first is of limited use only. Due to intensive fragmentation only weak molecular ions are observed. In contrast, the chemical ionization yields in better results. Dominant quasi molecular ions enable an unambiguous determination of the molecular weight. Moreover, characteristic fragment ions provide important indications of certain structural features of the examined compounds. Nevertheless, in some cases the chromatographic resolution was insufficient in order to separate all compounds present in natural lipid mixtures. Owing to the selected detection with mass spectrometry

Loading Effects on Resolution in Thin Layer Chromatography and ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 11. Loading Effects on Resolution in Thin Layer Chromatography and Paper Chromatography. K Girigowda V H Mulimani. Classroom Volume 10 Issue 11 November 2005 pp 79-84 ...

Gas Chromatography-Mass Spectroscopic (GC-MS) Analysis of n ...

African Journals Online (AJOL)

tuber-regium (synonym Pleurotus tuber regium) using gas chromatography-mass spectroscopic (GC-. MS) techniques. Methods: The n-hexane extract of the sclerotia ... Soxhlet extraction and analysed using gas chromatography-mass spectroscopic (MS) techniques. ..... Phytochemical composition of Pleurotus tuber regium.

Optimisation, simulation, and training in ion chromatography - all for free!

International Nuclear Information System (INIS)

Dicinoski, G.W.; Shaw, M.J.; Madden, J.E.; Haddad, P.R.

2001-01-01

Since its inception in 1975, ion chromatography (IC) has grown to become a powerful separation tool for the analytical chemist. Today, when scientists refer to the term IC, they mean a collection of chromatographic techniques suitable for the separation of inorganic ions and low molecular weight, water-soluble, organic compounds. The range of chromatographic techniques covered by this designation includes: ion-exchange chromatography; reversed-phase ion-interaction chromatography; and ion-exclusion chromatography. The optimization of the IC separation process is extremely time-consuming. A computer simulation software, Virtual Column 2, that accurately mimic retention behaviour in IC, is presented. It is based on large datasets of experimentally measured retention times; an ideal tool for chromatographers

Csaba Horváth and preparative liquid chromatography.

Science.gov (United States)

Guiochon, Georges

2005-06-24

Few chromatographers have been interested in furthering preparative liquid chromatography. The pioneers, Tswett, Kuhn and Lederer, A.J.P. Martin, Tiselius, isolated fractions but as an intermediate step in the analysis of their samples. The progress in electronics and sensors, and in their miniaturization has lead to the paradoxical situation that the analysts never see the transient pure fractions that their detector quantitates. Yet, over the last 25 years, preparative liquid chromatography has become an important industrial process for the separation, the extraction, and/or the purification of many pharmaceuticals or pharmaceutical intermediates, including pure enantiomers, purified peptides and proteins, compounds that are manufactured at the relatively large industrial scale of a few kilograms to several hundred tons per year. This development that has strongly affected the modem pharmaceutical industry is mainly due to the pioneering work of Csaba Horváth. His work in preparative HPLC was critical at both the practical and the theoretical levels. He was the first scientist in modem times to pay serious attention to the relationships between the curvature of the equilibrium isotherms, the competitive nature of nonlinear isotherms, and the chromatographic band profiles of complex mixtures. The thermodynamics of multi-component phase equilibria and mass transfer kinetics in chromatography attracted his interest and were the focus of ground-breaking contributions. He investigated displacement chromatography, an old method invented by Tiselius that Csaba was first to implement in HPLC. This choice was explained by the essential characteristic of displacement chromatography, in that it delivers fractions that can be far more concentrated than the feed. Remarkably, once the basics of nonlinear chromatography had been mastered in his group, most of the applications that were studied by his coworkers dealt with peptides of various sizes and with proteins. Thus, all

Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2016-04-01

In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of Separation and Identification of the Active Ingredients in Gardenia jasminoides Ellis Based on a Two-Dimensional Liquid Chromatography by Coupling Reversed Phase Liquid Chromatography and Hydrophilic Interaction Liquid Chromatography.

Science.gov (United States)

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2017-01-01

In this paper, by coupling reversed phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), a two-dimensional liquid chromatography system was developed for separation and identification of the active ingredients in Gardenia jasminoides Ellis (GJE). By applying the semi-preparative C18 column as the first dimension and the core-shell column as the second dimension, a total of 896 peaks of GJE were separated. Among the 896 peaks, 16 active ingredients including geniposide, gardenoside, gardoside, etc. were identified by mass spectrometry analysis. The results indicated that the proposed two-dimensional RPLC/HILIC system was an effective method for the analysis of GJE and might hold a high potential to become a useful tool for analysis of other complex mixtures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Spiral Countercurrent Chromatography

Science.gov (United States)

Ito, Yoichiro; Knight, Martha; Finn, Thomas M.

2013-01-01

For many years, high-speed countercurrent chromatography conducted in open tubing coils has been widely used for the separation of natural and synthetic compounds. In this method, the retention of the stationary phase is solely provided by the Archimedean screw effect by rotating the coiled column in the centrifugal force field. However, the system fails to retain enough of the stationary phase for polar solvent systems such as the aqueous–aqueous polymer phase systems. To address this problem, the geometry of the coiled channel was modified to a spiral configuration so that the system could utilize the radially acting centrifugal force. This successfully improved the retention of the stationary phase. Two different types of spiral columns were fabricated: the spiral disk assembly, made by stacking multiple plastic disks with single or four interwoven spiral channels connected in series, and the spiral tube assembly, made by inserting the tetrafluoroethylene tubing into a spiral frame (spiral tube support). The capabilities of these column assemblies were successfully demonstrated by separations of peptides and proteins with polar two-phase solvent systems whose stationary phases had not been well retained in the earlier multilayer coil separation column for high-speed countercurrent chromatography. PMID:23833207

21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from a...

Gas chromatography: mass selective detector

International Nuclear Information System (INIS)

Lapinskas, R.

1988-01-01

The mechanism of mass spectrometry technique directed for detecting molecular structures is described, with some considerations about its operational features. This mass spectrometer is used as a gas chromatography detector. (author)

Size-exclusion chromatography using core-shell particles.

Science.gov (United States)

Pirok, Bob W J; Breuer, Pascal; Hoppe, Serafine J M; Chitty, Mike; Welch, Emmet; Farkas, Tivadar; van der Wal, Sjoerd; Peters, Ron; Schoenmakers, Peter J

2017-02-24

Size-exclusion chromatography (SEC) is an indispensable technique for the separation of high-molecular-weight analytes and for determining molar-mass distributions. The potential application of SEC as second-dimension separation in comprehensive two-dimensional liquid chromatography demands very short analysis times. Liquid chromatography benefits from the advent of highly efficient core-shell packing materials, but because of the reduced total pore volume these materials have so far not been explored in SEC. The feasibility of using core-shell particles in SEC has been investigated and contemporary core-shell materials were compared with conventional packing materials for SEC. Columns packed with very small core-shell particles showed excellent resolution in specific molar-mass ranges, depending on the pore size. The analysis times were about an order of magnitude shorter than what could be achieved using conventional SEC columns. Copyright © 2016 Elsevier B.V. All rights reserved.

Diamond based adsorbents and their application in chromatography.

Science.gov (United States)

Peristyy, Anton A; Fedyanina, Olga N; Paull, Brett; Nesterenko, Pavel N

2014-08-29

The idea of using diamond and diamond containing materials in separation sciences has attracted a strong interest in the past decade. The combination of a unique range of properties, such as chemical inertness, mechanical, thermal and hydrolytic stability, excellent thermal conductivity with minimal thermal expansion and intriguing adsorption properties makes diamond a promising material for use in various modes of chromatography. This review summarises the recent research on the preparation of diamond and diamond based stationary phases, their properties and chromatographic performance. Special attention is devoted to the dominant retention mechanisms evident for particular diamond containing phases, and their subsequent applicability to various modes of chromatography, including chromatography carried out under conditions of high temperature and pressure. Copyright © 2014 Elsevier B.V. All rights reserved.

Gas chromatography

International Nuclear Information System (INIS)

Cram, S.P.; Risby, T.H.; Field, L.R.; Yu, W.L.

1980-01-01

In addition to the published literature for the years 1978 - 79, this review of developments in the field of gas chromatography includes earlier articles of particular significance appearing in foreign journals and the patent literature which was not available at the time of the previous review. The articles cited were selected as presenting the most fundamental developments in theory, methodology, and instrumentation. Some applications are cited if they reflect an advance in the state-of-the-art or have particular relevance to new developments. 1149 references are cited

Use of chelating agents as immovable phase in extraction chromatography

International Nuclear Information System (INIS)

Sebesta, F.

1978-01-01

Extraction chromatography using chelating agents is reviewed. The theory of element extraction by chelating agents and factors influencing this process (pH, extracting agent concentration in organic phase, masking agent concentration in aqueous phase) are briefly considered. The effect of kinetic factors on the extraction chromatography process is discussed. Ways of preparing columns are emphasized. Examples of using chelating reagents in various extraction chromatography systems are given. β-Diketones, oximes, hydroxamic acids, dithizon, diethyl dithiocarbamic acid are chosen as chelating agents

Research activities of MPA, Stuttgart University, for enhanced safety and reliability of components under complex load; Forschungsaktivitaeten der MPA Universitaet Stuttgart zu Erhoehung der Sicherheit und Zuverlaessigkeit komplex beanspruchter Bauteile

Energy Technology Data Exchange (ETDEWEB)

Herter, K.H.; Roos, E.; Schuler, X.; Maile, K. [Materialpruefungsanstalt (MPA), Univ. Stuttgart, Stuttgart (Germany)

2004-07-01

MPA research activities focus on fracture prevention and on the development of a generally applicable method of component integrity testing which, independent of the safety relevance of the components involved, is also part of ageing management. (orig.) [German] Die Forschungsaktivitaeten an der MPA im Hinblick auf die Erhoehung der Sicherheit und Zuverlaessigkeit komplex beanspruchter Bauteile orientieren sich an den Grundgedanken des Basissicherheitskonzepts (Prinzip des Bruchausschlusses). Zielsetzung war dabei die Entwicklung eines allgemein anwendbaren Nachweisverfahrens zur Komponentenintegritaet, das, abhaengig von der sicherheitstechnischen Relevanz der zu betrachtenden Komponenten, auch Bestandteil des Alterungsmanagements ist. (orig.)

Affinity monolith chromatography: A review of principles and recent analytical applications

Science.gov (United States)

Pfaunmiller, Erika L.; Paulemond, Marie Laura; Dupper, Courtney M.; Hage, David S.

2012-01-01

Affinity monolith chromatography (AMC) is a type of liquid chromatography that uses a monolithic support and a biologically-related binding agent as a stationary phase. AMC is a powerful method for the selective separation, analysis or studies of specific target compounds in a sample. This review discusses the basic principles of AMC and recent developments or applications of this method, with particular emphasis being given to work that has appeared in the last five years. Various materials that have been used to prepare columns for AMC are examined, including organic monoliths, silica monoliths, agarose monoliths and cryogels. These supports have been used in AMC for formats that have ranged from traditional columns to disks, microcolumns and capillaries. Many binding agents have also been employed in AMC, such as antibodies, enzymes, proteins, lectins, immobilized metal-ions and dyes. Some applications that have been reported with these binding agents in AMC are bioaffinity chromatography, immunoaffinity chromatography or immunoextraction, immobilized metal-ion affinity chromatography, dye-ligand affinity chromatography, chiral separations and biointeraction studies. Examples are presented from fields that include analytical chemistry, pharmaceutical analysis, clinical testing and biotechnology. Current trends and possible future directions in AMC are also discussed. PMID:23187827

Advances in immobilized artificial membrane (IAM) chromatography for novel drug discovery.

Science.gov (United States)

Tsopelas, Fotios; Vallianatou, Theodosia; Tsantili-Kakoulidou, Anna

2016-01-01

The development of immobilized artificial membrane (IAM) chromatography has unfolded new perspectives for the use of chromatographic techniques in drug discovery, combining simulation of the environment of cell membranes with rapid measurements. The present review describes the characteristics of phosphatidylcholine-based stationary phases and analyses the molecular factors governing IAM retention in comparison to n-octanol-water and liposomes partitioning systems as well as to reversed phase chromatography. Other biomimetic stationary phases are also briefly discussed. The potential of IAM chromatography to model permeability through the main physiological barriers and drug membrane interactions is outlined. Further applications to calculate complex pharmacokinetic properties, related to tissue binding, and to screen drug candidates for phospholipidosis, as well as to estimate cell accumulation/retention are surveyed. The ambivalent nature of IAM chromatography, as a border case between passive diffusion and binding, defines its multiple potential applications. However, despite its successful performance in many permeability and drug-membrane interactions studies, IAM chromatography is still used as a supportive and not a stand-alone technique. Further studies looking at IAM chromatography in different biological processes are still required if this technique is to have a more focused and consistent application in drug discovery.

Was der Religionspädagogik zu denken gibt. Exegetische Denkanstöße.

Directory of Open Access Journals (Sweden)

Jeremia Josef M. Mayr

2014-07-01

Full Text Available ENGLISH: The following article addresses three exegetical impulses which should be understood as food for thought to religious education. The first concentrates on the relation between exegesis and religious education because of the importance of reflecting on the concrete design of this special relation. The second centers what is indeed the centre of exegesis and religious education: the biblical text itself and the question of its real role and ways to handle it. Finally follows the presentation of a model of interaction with texts trying to equally respect all participants of this process. Simultaneously, this approach arranges a scope for the concrete biblical text allowing it to speak. This model is composed of three central steps: analysis (an exactly methodic procedure, interpretation (based on analysis, posing the question of meaning and appropriation (individually existential meaning. DEUTSCH: Der vorliegende Beitrag möchte aus exegetischer Perspektive drei Denkanstöße an die Religionspädagogik richten. Zunächst wird der Blick auf das Verhältnis zwischen Exegese und Religionspädagogik gelenkt, denn die Gestaltung dieses Verhältnisses ist entscheidend. Der zweite Denkanstoß rückt in die Mitte, was tatsächlich Mittelpunkt der Exegese und der Bibeldidaktik ist: den Text der Bibel selbst und die Frage, wie mit ihm umgegangen wird. Danach soll ein Modell der Textannäherung vorgestellt werden, das es ermöglichen will, mit Blick auf die Beteiligten auch den Texten genügend Raum zu geben, damit sie tatsächlich sprechen können. Die drei zentralen Teile dieses Modells sind Analyse (genaues methodisches Vorgehen, Interpretation (darauf aufbauend die Frage nach der Bedeutung und Aneignung (persönlich-existentielle Bedeutung.

Carbon nanotube based stationary phases for microchip chromatography

DEFF Research Database (Denmark)

Mogensen, Klaus Bo; Kutter, Jörg Peter

2012-01-01

already been demonstrated in more classical formats, for improved separation performance in gas and liquid chromatography, and for unique applications in solid phase extraction. Carbon nanotubes are now also entering the field of microfluidics, where there is a large potential to be able to provide......The objective of this article is to provide an overview and critical evaluation of the use of carbon nanotubes and related carbon-based nanomaterials for microchip chromatography. The unique properties of carbon nanotubes, such as a very high surface area and intriguing adsorptive behaviour, have...... integrated, tailor-made nanotube columns by means of catalytic growth of the nanotubes inside the fluidic channels. An evaluation of the different implementations of carbon nanotubes and related carbon-based nanomaterials for microfluidic chromatography devices is given in terms of separation performance...

Alexandru Popa, Untersuchungen zu den römisch-barbarischen Kontakten Östlich der römischen Provinz Dacia Antiquitatis reihe 3 Abhnadlungen zur vor-und frühgeschichte, zur klassichen und provinzial-römischen archäologie und zur geschichte des altertum

Directory of Open Access Journals (Sweden)

Vasile Iarmulschi

2016-06-01

Full Text Available Review on book - Alexandru Popa, Untersuchungen zu den römisch-barbarischen Kontakten Östlich der römischen Provinz Dacia Antiquitatis reihe 3 Abhnadlungen zur vor-und frühgeschichte, zur klassichen und provinzial-römischen archäologie und zur geschichte des altertum

Liquid chromatography and supercritical fluid chromatography as alternative techniques to gas chromatography for the rapid screening of anabolic agents in urine.

Science.gov (United States)

Desfontaine, Vincent; Nováková, Lucie; Ponzetto, Federico; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

2016-06-17

This work describes the development of two methods involving supported liquid extraction (SLE) sample treatment followed by ultra-high performance liquid chromatography or ultra-high performance supercritical fluid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and UHPSFC-MS/MS) for the screening of 43 anabolic agents in human urine. After evaluating different stationary phases, a polar-embedded C18 and a diol columns were selected for UHPLC-MS/MS and UHPSFC-MS/MS, respectively. Sample preparation, mobile phases and MS conditions were also finely tuned to achieve highest selectivity, chromatographic resolution and sensitivity. Then, the performance of these two methods was compared to the reference routine procedure for steroid analyses in anti-doping laboratories, which combines liquid-liquid extraction (LLE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For this purpose, urine samples spiked with the compounds of interest at five different concentrations were analyzed using the three analytical platforms. The retention and selectivity of the three techniques were very different, ensuring a good complementarity. However, the two new methods displayed numerous advantages. The overall procedure was much faster thanks to high throughput SLE sample treatment using 48-well plates and faster chromatographic analysis. Moreover, the highest sensitivity was attained using UHPLC-MS/MS with 98% of the doping agents detected at the lowest concentration level (0.1ng/mL), against 76% for UHPSFC-MS/MS and only 14% for GC-MS/MS. Finally, the weakest matrix effects were obtained with UHPSFC-MS/MS with 76% of the analytes displaying relative matrix effect between -20 and 20%, while the GC-MS/MS reference method displayed very strong matrix effects (over 100%) for all of the anabolic agents. Copyright © 2016 Elsevier B.V. All rights reserved.

21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

Science.gov (United States)

Doshi, Gaurav Mahesh; Une, Hemant Devidas

2016-01-01

In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

Science.gov (United States)

Doshi, Gaurav Mahesh; Une, Hemant Devidas

2016-01-01

Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

Ion chromatography of anions in the primary and secondary circuit

International Nuclear Information System (INIS)

Brandt, F.; Trost, R.

1984-01-01

Ion chromatography - though based on the same, well-established basic principles as gas chromatography and high pressure fluid chromatography - has made an actual breakthrough only in recent years. The adaptability of the process permits the measurement of samples of different composition or concentration. Some of the experience which has been accumulated in the laboratory at Goesgen nuclear power station during the last two years, is reported. This relates particularly to the composition of the samples, the need to use extremely pure calibration samples, the choice of special laboratory accessories and the like. (orig.) [de

RNase-assisted RNA chromatography

Science.gov (United States)

Michlewski, Gracjan; Cáceres, Javier F.

2010-01-01

RNA chromatography combined with mass spectrometry represents a widely used experimental approach to identify RNA-binding proteins that recognize specific RNA targets. An important drawback of most of these protocols is the high background due to direct or indirect nonspecific binding of cellular proteins to the beads. In many cases this can hamper the detection of individual proteins due to their low levels and/or comigration with contaminating proteins. Increasing the salt concentration during washing steps can reduce background, but at the cost of using less physiological salt concentrations and the likely loss of important RNA-binding proteins that are less stringently bound to a given RNA, as well as the disassembly of protein or ribonucleoprotein complexes. Here, we describe an improved RNA chromatography method that relies on the use of a cocktail of RNases in the elution step. This results in the release of proteins specifically associated with the RNA ligand and almost complete elimination of background noise, allowing a more sensitive and thorough detection of RNA-binding proteins recognizing a specific RNA transcript. PMID:20571124

Theories to support method development in comprehensive two-dimensional liquid chromatography - A review

NARCIS (Netherlands)

Bedani, F.; Schoenmakers, P.J.; Janssen, H.-G.

2012-01-01

On-line comprehensive two-dimensional liquid chromatography techniques promise to resolve samples that current one-dimensional liquid chromatography methods cannot adequately deal with. To make full use of the potential of two-dimensional liquid chromatography, optimization is required. Optimization

Selectivity in microemulsion electrokinetic chromatography

DEFF Research Database (Denmark)

Pedersen-Bjergaard, S; Gabel-Jensen, Charlotte; Honoré Hansen, S

2000-01-01

Microemulsion electrokinetic chromatography (MEEKC) is a most promising separation technique providing good selectivity and high separation efficiency of anionic, cationic as well as neutral solutes. In MEEKC lipophilic organic solvents dispersed as tiny droplets in an aqueous buffer by the use...

Compound immobilization and drug-affinity chromatography.

Science.gov (United States)

Rix, Uwe; Gridling, Manuela; Superti-Furga, Giulio

2012-01-01

Bioactive small molecules act through modulating a yet unpredictable number of targets. It is therefore of critical importance to define the cellular target proteins of a compound as an entry point to understanding its mechanism of action. Often, this can be achieved in a direct fashion by chemical proteomics. As with any affinity chromatography, immobilization of the bait to a solid support is one of the earliest and most crucial steps in the process. Interfering with structural features that are important for identification of a target protein will be detrimental to binding affinity. Also, many molecules are sensitive to heat or to certain chemicals, such as acid or base, and might be destroyed during the process of immobilization, which therefore needs to be not only efficient, but also mild. The subsequent affinity chromatography step needs to preserve molecular and conformational integrity of both bait compound and proteins in order to result in the desired specific enrichment while ensuring a high level of compatibility with downstream analysis by mass spectrometry. Thus, the right choice of detergent, buffer, and protease inhibitors is also essential. This chapter describes a widely applicable procedure for the immobilization of small molecule drugs and for drug-affinity chromatography with subsequent protein identification by mass spectrometry.

Use of micro gas chromatography in the fuel cycle of fusion reactors

International Nuclear Information System (INIS)

Laesser, R.; Gruenhagen, S.; Kawamura, Y.

2003-01-01

Various analytical techniques exist to determine the compositions of gases handled in the fuel cycle of future fusion machines. Gas chromatography was found to be the most appropriate method. The main disadvantages of conventional gas chromatography were the long retention times for the heavy hydrogen species of >30 min. Recent progress in the development of micro-gas chromatography has reduced these retention times to ∼3 min. The usefulness of micro-gas chromatography for the analysis of hydrogen and impurity gas mixtures in the fuel cycle of future fusion machines is presented and the advantages and drawbacks are discussed

Fabrication of Ceramic Membrane Chromatography for Biologics Purification

Directory of Open Access Journals (Sweden)

Maizirwan Mel

2011-12-01

Full Text Available Chromatography is one of the most important separation processes of choice for the recovery/purification of proteins and complex bio-structures. Fabrication of chromatographic membranes and their efficiency in the chromatography process has been the subject of many recent researches. In this study, a coin-like, 13 mm diameter and 3 mm thick, ceramic membrane was fabricated to be used as a chromatographic medium. The membrane is used to replace the conventional resin-based chromatography columns. Hydroxyapatite (HA powder was used as a material for the membrane fabrication. In this project, a HA powder was produced using starch as pore creating agents. Characterization processes were done for the ceramic membrane using the suitable apparatuses. Three parameters of the fabrication process (starch wt %, compaction pressure and sintering temperature were manipulated to optimize the performance of the membrane. The fabricated membrane was placed in a (FPLC system to be tested for its performance as an adsorptive membrane. (IMAC process was run by immobilizing Ni2+ ions at the membrane particles surfaces. NP protein of the (NDV was used to test the membrane's ability to bind Histidine-tagged proteins. The optimum set of process parameters that yielded in the highest porosity and good chromatogram was determined to be 5 wt % starch, 3000 psi compaction pressure and 1100°C sintering temperature.ABSTRAK: Kromatografi merupakan satu daripada proses pengasingan yang penting yang dipilih untuk perolehan/penapisan protein dan biostruktur yang kompleks. Pemfabrikatan membran kromatografi dan kecekapannya dalam proses kromatografi merupakan fokus beberapa kajian terkini. Dalam kajian ini, membran seramik berbentuk duit syiling, berdiameter 13 mm dengan ketebalan 3 mm, direka untuk digunakan sebagai perantara kromatografi. Membran ini digunakan untuk menggantikan turus kromatografi berasaskan resin yang lazim. Serbuk hidroksiapatit (HA digunakan sebagai bahan

Study of radiolysis products of natural organic materials by means of gas chromatography

International Nuclear Information System (INIS)

Pogocki, D.

1994-01-01

Analytical methods based on gas chromatography for identification determination of products arising during food irradiation have been presented. Behind the classics version of the methods one has shown also combined methods being the on-line connection of gas chromatography with mass spectroscopy as well as gas chromatography with liquid chromatography and mass spectroscopy. The applicability as well as weakness and advantages of each version have been discussed on the context of food irradiation. 11 refs, 7 figs

Integrated sampling vs ion chromatography: Mathematical considerations

International Nuclear Information System (INIS)

Sundberg, L.L.

1992-01-01

This paper presents some general purpose considerations that can be utilized when comparisons are made between the results of integrated sampling over several hours or days, and ion chromatography where sample collection times are measured in minutes. The discussion is geared toward the measurement of soluble transition metal ions in BWR feedwater. Under steady-state conditions, the concentrations reported by both techniques should be in reasonable agreement. Transient operations effect both types of measurements. A simplistic model, applicable to both sampling techniques, is presented that demonstrates the effect of transients which occur during the acquisition of a steady-state sample. For a common set of conditions, the integrated concentration is proportional to the concentration and duration of the transient, and inversely proportional to the sample collection time. The adjustment of the collection period during a known transient allows an estimation of peak transient concentration. Though the probability of sampling a random transient with the integrated sampling technique is very high, the magnitude is severely diluted with long integration times. Transient concentrations are magnified with ion chromatography, but the probability of sampling a transient is significantly lower using normal ion chromatography operations. Various data averaging techniques are discussed for integrated sampling and IC determinations. The use of time-weighted averages appears to offer more advantages over arithmetic and geometric means for integrated sampling when the collection period is variable. For replicate steady-state ion chromatography determinations which bracket a transient sample, it may be advantageous to ignore the calculation of averages, and report the data as trending information only

DIRECT-DEPOSITION INFRARED SPECTROMETRY WITH GAS AND SUPERCRITICAL FLUID CHROMATOGRAPHY

Science.gov (United States)

A direct-deposition Fourier transform infrared (FT-IR) system has been evaluated for applicability to gas chromatography (GC) and supercritical fluid chromatography (SFC) of environmental analytes. A 100-um i.d. fused-silica transfer line was used for GC, and a 50-um transfer lin...

Liquid phase chromatography on microchips

DEFF Research Database (Denmark)

Kutter, Jörg Peter

2012-01-01

explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...

Separation of Aeruginosin-865 from Cultivated Soil Cyanobacterium (Nostoc sp.) by Centrifugal Partition Chromatography combined with Gel Permeation Chromatography.

Science.gov (United States)

Cheel, José; Minceva, Mirjana; Urajová, Petra; Aslam, Rabya; Hrouzek, Pavel; Kopecký, Jiří

2015-10-01

Aeruginosin-865 was isolated from cultivated soil cyanobacteria using a combination of centrifugal partition chromatography (CPC) and gel permeation chromatography. The solubility of Aer-865 in different solvents was evaluated using the conductor-like screening model for real solvents (COSMO-RS). The CPC separation was performed in descending mode with a biphasic solvent system composed of water-n-BuOH-acetic acid (5:4:1, v/v/v). The upper phase was used as a stationary phase, whereas the lower phase was employed as a mobile phase at a flow rate of 10 mL/min. The revolution speed and temperature of the separation column were 1700 rpm and 25 degrees C, respectively. Preparative CPC separation followed by gel permeation chromatography was performed on 50 mg of crude extract yielding Aer-865 (3.5 mg), with a purity over 95% as determined by HPLC. The chemical identity of the isolated compound was confirmed by comparing its spectroscopic data (UV, HRESI-MS, HRESI-MS/MS) with those of an authentic standard and data available in the literature.

Ultra-high Performance Liquid Chromatography in Steroid Analysis

OpenAIRE

Salonen, Fanny

2017-01-01

The latest version of liquid chromatography is ultra-high performance (or pressure) chromatography (UHPLC). In the technique, short and narrow-bore columns with particle sizes below 3 µm are used. The extremely high pressure used results in very short analysis times, excellent separation, and good resolution. This makes UHPLC a good choice for steroidal analysis. Steroids are a highly interesting area of study; they can be recognized as biomarkers for several diseases and are a relevant topic...

Gas chromatography of β-diketonates

International Nuclear Information System (INIS)

Burgett, C.A.

1976-01-01

The history of separation of metal complexes by gas chromatography is reviewed. The greatest success has been achieved with metal halides or metal β-diketonates, particularly with chelates of the small elements, Be and Al, and the extremely inert chromium diketonates. Many problems still remain concerning the development of suitable chromatographic techniques for many chelates; however, the technique of synergic solvent extraction, mixed-ligand complex chromatography, the synthesis of new heteroatomic ligands, and the advent of new liquid phases are discussed as means to increase the number of unique techniques for separation and analysis of metals. Methods are suggested and references are cited for chromatographic analysis of elements in the following groups: alkali metals, alkaline earths, Group IIIA, IVB, VB, VIB, VIIB, VIII, IB, and IIB. Special attention is given to separation of the volatile complexes of Sc, Y, the lanthanides, the actinides, and Pb. 156 references

Lipidomics by Supercritical Fluid Chromatography

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Laurent Laboureur

2015-06-01

Full Text Available This review enlightens the role of supercritical fluid chromatography (SFC in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC. It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering or highly specific (mass spectrometry detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides defined by the LIPID MAPS consortium.

Lipidomics by Supercritical Fluid Chromatography

Science.gov (United States)

Laboureur, Laurent; Ollero, Mario; Touboul, David

2015-01-01

This review enlightens the role of supercritical fluid chromatography (SFC) in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC). It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering) or highly specific (mass spectrometry) detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides) defined by the LIPID MAPS consortium. PMID:26090714

Dust precipitation nuisance in the Rhine lignite basin. Situation analysis, legal assessment and the use of compost recycling for emission-protection purposes; Die Staubniederschlagsbelastungen im Rheinischen Braunkohlenrevier. Situationsanalyse, rechtliche Bewertung und Verwertung von Kompost zu Immissionsschutzzwecken

Energy Technology Data Exchange (ETDEWEB)

Asenbaum, P. [Bergamt Dueren (Germany)

2004-03-01

The paper describes the problem of dust precipitation in the Rhine lignite basin and presents a legal, scientific and technical assessment of how composting can be used for emission protection purposes, along with supporting measures such as the replanting of opencast mining sites. Also examines the benefits, and possible risks, associated with waste recycling projects of this kind. The results of the investigations show that compost recycling for emission-protection purposes can be used to support the emission-protection measures previously deployed at opencast mines in the Rhine lignite basin, including the grassing-over of former mine sites. Such measures are now considered to be technically feasible, environmentally compatible and lawful, and indeed are considered necessary in some circumstances. (orig.) [German] Die Arbeit beschreibt die Staubniederschlagsbelastungen im Rheinischen Braunkohlenrevier und bewertet in diesem Zusammenhang den Einsatz von Kompost zu Immissionsschutzzwecken einschliesslich einer unterstuetzenden Begruenung in den Tagebauen in rechtlicher sowie naturwissenschaftlich-technischer Hinsicht. Darueber hinaus wird die Nuetzlichkeit und Schadlosigkeit dieser Abfallverwertungsmassnahmen beurteilt. Nach den Ergebnissen dieser Arbeit ist eine Kompostverwertung zu Immissionsschutzzwecken zur Ergaenzung des bisherigen Immissionsschutzsystems in den Tagebauen des Rheinischen Braunkohlenreviers einschliesslich einer unterstuetzenden Begruenung technisch moeglich, umweltvertraeglich und rechtlich zulaessig sowie unter bestimmten Voraussetzungen erforderlich. (orig.)

Applications of hydrophilic interaction chromatography to amino acids, peptides, and proteins.

Science.gov (United States)

Periat, Aurélie; Krull, Ira S; Guillarme, Davy

2015-02-01

This review summarizes the recent advances in the analysis of amino acids, peptides, and proteins using hydrophilic interaction chromatography. Various reports demonstrate the successful analysis of amino acids under such conditions. However, a baseline resolution of the 20 natural amino acids has not yet been published and for this reason, there is often a need to use mass spectrometry for detection to further improve selectivity. Hydrophilic interaction chromatography is also recognized as a powerful technique for peptide analysis, and there are a lot of papers showing its applicability for proteomic applications (peptide mapping). It is expected that its use for peptide mapping will continue to grow in the future, particularly because this analytical strategy can be combined with reversed-phase liquid chromatography, in a two-dimensional setup, to reach very high resolving power. Finally, the interest in hydrophilic interaction chromatography for intact proteins analysis is less evident due to possible solubility issues and a lack of suitable hydrophilic interaction chromatography stationary phases. To date, it has been successfully employed only for the characterization of membrane proteins, histones, and the separation of glycosylated isoforms of an intact glycoprotein. From our point of view, the number of hydrophilic interaction chromatography columns compatible with intact proteins (higher upper temperature limit, large pore size, etc.) is still too limited. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

Science.gov (United States)

Johnson, Brian J.

2014-01-01

Ion exchange chromatography is an important technique in the separation of charged species, particularly in biological, inorganic, and environmental samples. In this experiment, students are supplied with a mixture of two substitution-inert complex ions. They separate the complexes by ion exchange chromatography using a "flash"…

Use and practice of achiral and chiral supercritical fluid chromatography in pharmaceutical analysis and purification.

Science.gov (United States)

Lemasson, Elise; Bertin, Sophie; West, Caroline

2016-01-01

The interest of pharmaceutical companies for complementary high-performance chromatographic tools to assess a product's purity or enhance this purity is on the rise. The high-throughput capability and economic benefits of supercritical fluid chromatography, but also the "green" aspect of CO2 as the principal solvent, render supercritical fluid chromatography very attractive for a wide range of pharmaceutical applications. The recent reintroduction of new robust instruments dedicated to supercritical fluid chromatography and the progress in stationary phase technology have also greatly benefited supercritical fluid chromatography. Additionally, it was shown several times that supercritical fluid chromatography could be orthogonal to reversed-phase high-performance liquid chromatography and could efficiently compete with it. Supercritical fluid chromatography is an adequate tool for small molecules of pharmaceutical interest: synthetic intermediates, active pharmaceutical ingredients, impurities, or degradation products. In this review, we first discuss about general chromatographic conditions for supercritical fluid chromatography analysis to better suit compounds of pharmaceutical interest. We also discuss about the use of achiral and chiral supercritical fluid chromatography for analytical purposes and the recent applications in these areas. The use of preparative supercritical fluid chromatography by pharmaceutical companies is also covered. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spillage detector for liquid chromatography systems

Science.gov (United States)

Jarvis, M. J.; Fulton, D. S. (Inventor)

1986-01-01

A spillage detector device for use in conjunction with fractionation of liquid chromatography systems which includes a spillage recieving enclosure beneath the fractionation area is described. A sensing device having a plurality of electrodes of alternating polarity is mounted within the spillage recieving enclosure. Detection circuitry, responsive to conductivity between electrodes, is operatively connected to the sensing device. The detection circuitry feeds into the output circuitry. The output circuit has relaying and switching circuitry directed to a solenoid, an alarm system and a pump. The solenoid is connected to the pliable conduit of the chromatography system. The alarm system comprises an audio alarm and a visual signal. A 115-volt power system interconnected with the pump, the solenoid, the sensing device, and the detection and output circuitry.

Choices of capture chromatography technology in antibody manufacturing processes.

Science.gov (United States)

DiLeo, Michael; Ley, Arthur; Nixon, Andrew E; Chen, Jie

2017-11-15

The capture process employed in monoclonal antibody downstream purification is not only the most critically impacted process by increased antibody titer resulting from optimized mammalian cell culture expression systems, but also the most important purification step in determining overall process throughput, product quality, and economics. Advances in separation technology for capturing antibodies from complex feedstocks have been one focus of downstream purification process innovation for past 10 years. In this study, we evaluated new generation chromatography resins used in the antibody capture process including Protein A, cation exchange, and mixed mode chromatography to address the benefits and unique challenges posed by each chromatography approach. Our results demonstrate the benefit of improved binding capacity of new generation Protein A resins, address the concern of high concentration surge caused aggregation when using new generation cation exchange resins with over 100mg/mL binding capacity, and highlight the potential of multimodal cation exchange resins for capture process design. The new landscape of capture chromatography technologies provides options to achieve overall downstream purification outcome with high product quality and process efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

Radioanalytical determination of plutonium and americium using ion exchange and extraction chromatography technique in urine

International Nuclear Information System (INIS)

Santhanakrishnan, V.; Sreedevi, K.R.; Rajaram, S.; Ravi, P.M.

2011-01-01

The use of anion exchange chromatography for the separation of Pu and extraction chromatography technique for the separation of Am from urine samples was studied. In the earlier method, Pu separation was carried out by anion exchange chromatography followed by Am separation by cation exchange chromatography. The chemical recovery of Am obtained by cation exchange separation method was inconsistent and low in the range 30-70%. In this study, the average Pu recovery obtained using anion exchange chromatography was 89.2 with standard deviation of 10.4 and the average Am recovery obtained using extraction chromatography with TRU resin was 77.4 with standard deviation of 14.8. Moreover, Am separation could be completed within three hours using the TRU column compared to two days that were required for the cation exchange chromatography. (author)

No Escape from the Burbs. Rezension zu Roger Keil (Hg. (2013: Suburban Constellations: Governance, Land and Infrastructure in the 21st Century. Berlin: JOVIS.

Directory of Open Access Journals (Sweden)

Markus Kip

2016-11-01

Full Text Available Den Begriff des Urbanen in Auseinandersetzung mit dem Suburbanen zu bestimmen, ist horizonterweiternd. Nicht, dass er nach der Lektüre von Suburban Constellations an Schärfe gewonnen hätte, wohl aber hat sich meine Aufmerksamkeit für scheinbar banale Phänomene außerhalb der Stadt geschärft. Neu ist die enorme Bandbreite suburbaner Fallstudien aus dem ‚Globalen Norden‘ und dem ‚Globalen Süden‘, die hier versammelt werden.Der Band ist ein wichtiger Output des Forschungsverbunds „Global Suburbanism. Governance, Land and Infrastructure in the 21st Century“, dem über fünfzig Wissenschaftler_innen und Praktiker_innen angehörenAm Ende hat mich die Hauptthese des Buches überzeugt, der zufolge suburbane Räume keine Randphänomene, sondern Schlüsselaspekte der Urbanisierung im 21. Jahrhundert darstellen.

Feasibility of correlating separation of ternary mixtures of neutral analytes via thin layer chromatography with supercritical fluid chromatography in support of green flash separations.

Science.gov (United States)

Ashraf-Khorassani, M; Yan, Q; Akin, A; Riley, F; Aurigemma, C; Taylor, L T

2015-10-30

Method development for normal phase flash liquid chromatography traditionally employs preliminary screening using thin layer chromatography (TLC) with conventional solvents on bare silica. Extension to green flash chromatography via correlation of TLC migration results, with conventional polar/nonpolar liquid mixtures, and packed column supercritical fluid chromatography (SFC) retention times, via gradient elution on bare silica with a suite of carbon dioxide mobile phase modifiers, is reported. Feasibility of TLC/SFC correlation is individually described for eight ternary mixtures for a total of 24 neutral analytes. The experimental criteria for TLC/SFC correlation was assumed to be as follows: SFC/UV/MS retention (tR) increases among each of the three resolved mixture components; while, TLC migration (Rf) decreases among the same resolved mixture components. Successful correlation of TLC to SFC was observed for most of the polar organic solvents tested, with the best results observed via SFC on bare silica with methanol as the CO2 modifier and TLC on bare silica with a methanol/dichloromethane mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Continuous Membrane Chromatography Concepts with an Enhanced Process Simulation Approach

Directory of Open Access Journals (Sweden)

Steffen Zobel-Roos

2018-03-01

Full Text Available Modern biopharmaceutical products strive for small-scale, low-cost production. Continuous chromatography has shown to be a promising technology because it assures high-capacity utilization, purity and yield increases, and lower facility footprint. Membrane chromatography is a fully disposable low-cost alternative to bead-based chromatography with minor drawbacks in terms of capacity. Hence, continuous membrane chromatography should have a high potential. The evaluation of continuous processes goes often along with process modeling. Only few experiments with small feed demand need to be conducted to estimate the model parameters. Afterwards, a variety of different process setups and working points can be analyzed in a very short time, making the approach very efficient. Since the available modeling approaches for membrane chromatography modules did not fit the used design, a new modeling approach is shown. This combines the general rate model with an advanced fluid dynamic distribution. Model parameter determination and model validation were done with industrial cell cultures containing Immunoglobulin G (IgG. The validated model was used to evaluate the feasibility of the integrated Counter Current Chromatography (iCCC concept and the sequential chromatography concept for membrane adsorber modules, starting with a laboratory-type module used for sample preparation. A case study representing a fed-batch reactor with a capacity from 20 to 2000 L was performed. Compared to batch runs, a 71% higher capacity, 48.5% higher productivity, and 38% lower eluent consumption could be achieved.

Lipidomic analysis of biological samples: Comparison of liquid chromatography, supercritical fluid chromatography and direct infusion mass spectrometry methods.

Science.gov (United States)

Lísa, Miroslav; Cífková, Eva; Khalikova, Maria; Ovčačíková, Magdaléna; Holčapek, Michal

2017-11-24

Lipidomic analysis of biological samples in a clinical research represents challenging task for analytical methods given by the large number of samples and their extreme complexity. In this work, we compare direct infusion (DI) and chromatography - mass spectrometry (MS) lipidomic approaches represented by three analytical methods in terms of comprehensiveness, sample throughput, and validation results for the lipidomic analysis of biological samples represented by tumor tissue, surrounding normal tissue, plasma, and erythrocytes of kidney cancer patients. Methods are compared in one laboratory using the identical analytical protocol to ensure comparable conditions. Ultrahigh-performance liquid chromatography/MS (UHPLC/MS) method in hydrophilic interaction liquid chromatography mode and DI-MS method are used for this comparison as the most widely used methods for the lipidomic analysis together with ultrahigh-performance supercritical fluid chromatography/MS (UHPSFC/MS) method showing promising results in metabolomics analyses. The nontargeted analysis of pooled samples is performed using all tested methods and 610 lipid species within 23 lipid classes are identified. DI method provides the most comprehensive results due to identification of some polar lipid classes, which are not identified by UHPLC and UHPSFC methods. On the other hand, UHPSFC method provides an excellent sensitivity for less polar lipid classes and the highest sample throughput within 10min method time. The sample consumption of DI method is 125 times higher than for other methods, while only 40μL of organic solvent is used for one sample analysis compared to 3.5mL and 4.9mL in case of UHPLC and UHPSFC methods, respectively. Methods are validated for the quantitative lipidomic analysis of plasma samples with one internal standard for each lipid class. Results show applicability of all tested methods for the lipidomic analysis of biological samples depending on the analysis requirements

The compactness of front tracking for chromatography electrophoresis and incompressible multiphase flow

International Nuclear Information System (INIS)

Wendroff, B.

1992-01-01

An analysis of the equations of chromatography from the point of view of hyperbolic conservation laws has been reviewed in recent literature. Serre was able to prove that the Lax-Friedrichs difference scheme, Godunov's method, and the viscosity method, have a subsequence converging to a weak solution of the chromatography equations, with no restriction on the size of the initial data. The purpose of this note is to announce that two versions of front tracking can be added to this list. After a brief description of the properties of the chromatography system and a definition of front tracking we give the basic steps of the proof. An example showing the quality of a front tracking solution is given. The equations of idealized electrophoresis and multiphase incompressible flow are very similar to the chromatography equations, but the former have linearly degenerate characteristic field, creating contact discontinuities. In the final section we briefly indicate how our result for chromatography carries over to this case

Ion-pair chromatography of nucleic acid derivatives

International Nuclear Information System (INIS)

Perrone, P.A.; Brown, P.R.

1985-01-01

Little work has been done on the ion-pair chromatography of nucleic acid constituents, although there is a great potential for the use of this technique in the field. Since the classic work in 1949, nucleotides, as well as nucleosides and bases, have been separated by ion-exchange chromatography. However, ion exchange is a difficult mode and most researchers prefer the use of reversed-phase whenever possible. Although reversed-phase is now the method of choice, ionic compounds like nucleotides and some of the more polar bases are not adequately retained by many systems of this type. In addition, it is difficult to analyze simultaneously members of all three classes of nucleic acid compounds (bases, nucleosides, and nucleotides) using a reversed-phase system, even with gradient elution. Ion pairing can be a useful technique because, theoretically, the separation of nonionic bases and nucleosides along with the ionic nucleotides can be achieved. Additionally, each group of compounds may be separated isocratically. In this chapter, they will discuss ion-pair chromatography as applied to nucleic acid constituents. The current theories, advantages and disadvantages, a limited number of applications, and potential for future work are presented

Expanded-bed chromatography in primary protein purification.

Science.gov (United States)

Anspach, F B; Curbelo, D; Hartmann, R; Garke, G; Deckwer, W D

1999-12-31

Chromatography in stable expanded beds enables proteins to be recovered directly from cultivations of microorganisms or cells and preparations of disrupted cells, without the need for prior removal of suspended solids. The general performance of an expanded bed is comparable to a packed bed owing to reduced mixing of the adsorbent particles in the column. However, optimal operating conditions are more restricted than in a packed bed due to the dependence of bed expansion on the size and density of the adsorbent particles as well as the viscosity and density of the feedstock. The feedstock composition may become the most limiting restriction owing to interactions of adsorbent particles with cell surfaces, DNA and other substances, leading to their aggregation and consequently to bed instabilities and channeling. Despite these difficulties, expanded-bed chromatography has found widespread applications in the large scale purification of proteins from mammalian cell and microbial feedstocks in industrial bioprocessing. The basics and implementation of expanded-bed chromatography, its advantages as well as problems encountered in the use of this technique for the direct extraction of proteins from unclarified feedstocks are addressed.

The analysis of aqueous mixtures using liquid chromatography-electrospray mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Johnson, Steven [Iowa State Univ., Ames, IA (United States)

1999-02-12

The focus of this dissertation is the use of chromatographic methods coupled with electrospray mass spectrometry (ES-MS) for the determination of both organic and inorganic compounds in aqueous solutions. The combination of liquid chromatography (LC) methods and ES-MS offers one of the foremost methods for determining compounds in complex aqueous solutions. In this work, LC-ES-MS methods are devised using ion exclusion chromatography, reversed phase chromatography, and ion exchange chromatography, as well as capillary electrophoresis (CE). For an aqueous sample, these LC-ES-MS and CE-ES-MS techniques require no sample preparation or analyte derivatization, which makes it possible to observe a wide variety of analytes as they exist in solution. The majority of this work focuses on the use of LC-ES-MS for the determination of unknown products and intermediates formed during electrochemical incineration (ECI), an experimental waste remediation process. This report contains a general introduction to the project and the general conclusions. Four chapters have been removed for separate processing. Titles are: Chapter 2: Determination of small carboxylic acids by ion exclusion chromatography with electrospray mass spectrometry; Chapter 3: Electrochemical incineration of benzoquinone in aqueous media using a quaternary metal oxide electrode in the absence of a soluble supporting electrolyte; Chapter 4: The determination of electrochemical incineration products of 4-chlorophenol by liquid chromatography-electrospray mass spectrometry; and Chapter 5: Determination of small carboxylic acids by capillary electrophoresis with electrospray mass spectrometry.

Safety operation of chromatography column system with discharging hydrogen radiolytically generated

International Nuclear Information System (INIS)

Watanabe, S; Sano, Y.; Nomura, K.; Koma, Y.; Okamoto, Y.

2015-01-01

The extraction chromatography technology is one of the promising methods for the partitioning of minor actinides (Am and Cm) from spent nuclear fuels. In the extraction chromatography system, the accumulation of hydrogen gas in the chromatography column is suspected to lead to fire or explosion. In order to prevent hazardous accidents, it is necessary to evaluate behaviors of gas radiolytically generated inside the column. In this study, behaviors of gas inside the extraction chromatography column were investigated through experiments and Computation Fluid Dynamics (CFD) simulation. N_2 gas once accumulated as bubbles in the packed bed was hardly discharged by the flow of mobile phase. However, the CFD simulation and X-ray imaging on γ-ray irradiated column revealed that during operation the hydrogen gas generated in the column was dissolved into the mobile phase without accumulation and then discharged. (authors)

Reversed-phase liquid chromatography coupled on-line with capillary gas chromatography use of an anion-exchange membrane to remove an ion-pair reagent from the eluent.

NARCIS (Netherlands)

Brinkman, U.A.T.; Goosens, E.C.; de Jong, D.; de Jong, G.J.; Beerthuizen, I.M.

1995-01-01

In order to enable the coupling of reversed-phase liquid chromatography (RPLC) with capillary gas chromatography (GC), the performance of an anion-exchange micromembrane device has been studied to remove the ion-pair reagent methanesulphonic acid from an acetonitrile/water LC eluent. The regenerant

ANALYSIS AND IDENTIFICATION SPIKING CHEMICAL COMPOUNDS RELATED TO CHEMICAL WEAPON CONVENTION IN UNKNOWN WATER SAMPLES USING GAS CHROMATOGRAPHY AND GAS CHROMATOGRAPHY ELECTRON IONIZATION MASS SPECTROMETRY

Directory of Open Access Journals (Sweden)

Harry Budiman

2010-06-01

Full Text Available The identification and analysis of chemical warfare agents and their degradation products is one of important component for the implementation of the convention. Nowadays, the analytical method for determination chemical warfare agent and their degradation products has been developing and improving. In order to get the sufficient analytical data as recommended by OPCW especially in Proficiency Testing, the spiking chemical compounds related to Chemical Weapon Convention in unknown water sample were determined using two different techniques such as gas chromatography and gas chromatography electron-impact ionization mass spectrometry. Neutral organic extraction, pH 11 organic extraction, cation exchanged-methylation, triethylamine/methanol-silylation were performed to extract the chemical warfare agents from the sample, before analyzing with gas chromatography. The identification of chemical warfare agents was carried out by comparing the mass spectrum of chemicals with mass spectrum reference from the OPCW Central Analytical Database (OCAD library while the retention indices calculation obtained from gas chromatography analysis was used to get the confirmation and supported data of  the chemical warfare agents. Diisopropyl methylphosphonate, 2,2-diphenyl-2-hydroacetic acid and 3-quinuclidinol were found in unknown water sample. Those chemicals were classified in schedule 2 as precursor or reactant of chemical weapons compound in schedule list of Chemical Weapon Convention.   Keywords: gas chromatography, mass spectrometry, retention indices, OCAD library, chemical warfare agents

Preparative supercritical fluid chromatography: A powerful tool for chiral separations.

Science.gov (United States)

Speybrouck, David; Lipka, Emmanuelle

2016-10-07

In 2012, the 4 biggest pharmaceutical blockbusters were pure enantiomers and separating racemic mixtures is now frequently a key step in the development of a new drug. For a long time, preparative liquid chromatography was the technique of choice for the separation of chiral compounds either during the drug discovery process to get up to a hundred grams of a pure enantiomer or during the clinical trial phases needing kilograms of material. However the advent of supercritical Fluid Chromatography (SFC) in the 1990s has changed things. Indeed, the use of carbon dioxide as the mobile phase in SFC offers many advantages including high flow rate, short equilibration time as well as low solvent consumption. Despite some initial teething troubles, SFC is becoming the primary method for preparative chiral chromatography. This article will cover recent developments in preparative SFC for the separation of enantiomers, reviewing several aspects such as instrumentation, chiral stationary phases, mobile phases or purely preparative considerations including overloading, productivity or large scale chromatography. Copyright © 2016 Elsevier B.V. All rights reserved.

Adaptation to high throughput batch chromatography enhances multivariate screening.

Science.gov (United States)

Barker, Gregory A; Calzada, Joseph; Herzer, Sibylle; Rieble, Siegfried

2015-09-01

High throughput process development offers unique approaches to explore complex process design spaces with relatively low material consumption. Batch chromatography is one technique that can be used to screen chromatographic conditions in a 96-well plate. Typical batch chromatography workflows examine variations in buffer conditions or comparison of multiple resins in a given process, as opposed to the assessment of protein loading conditions in combination with other factors. A modification to the batch chromatography paradigm is described here where experimental planning, programming, and a staggered loading approach increase the multivariate space that can be explored with a liquid handling system. The iterative batch chromatography (IBC) approach is described, which treats every well in a 96-well plate as an individual experiment, wherein protein loading conditions can be varied alongside other factors such as wash and elution buffer conditions. As all of these factors are explored in the same experiment, the interactions between them are characterized and the number of follow-up confirmatory experiments is reduced. This in turn improves statistical power and throughput. Two examples of the IBC method are shown and the impact of the load conditions are assessed in combination with the other factors explored. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multidimensional chromatography coupled to mass spectrometry in analysing complex proteomics samples

NARCIS (Netherlands)

Horvatovich, Peter; Hoekman, Berend; Govorukhina, Natalia; Bischoff, Rainer

Multidimensional chromatography coupled to mass spectrometry (LC(n)-MS) provides more separation power and an extended measured dynamic concentration range to analyse complex proteomics samples than one dimensional liquid chromatography coupled to mass spectrometry (1D-LC-MS). This review gives an

VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis. Program. Summary of reports

International Nuclear Information System (INIS)

2001-01-01

Program and summary of reports of the VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis are performed. The meeting took place 15-19 October, 2001 in Moscow. Many problems of liquid and ion exchange chromatography, capillary electrophoresis, thin-layer chromatography have been discussed extensively. Reports covering properties of sorbents and devices for chromatography are incorporated in the collection [ru

Purification of radiolabeled RNA using sephadex G-15 or G-50 chromatography

International Nuclear Information System (INIS)

Yoo, Beong Gyu; Lee, Jong Seok

1998-01-01

We attempted to purify radiolabeled RNA using Sephadex G-15 and G-50 chromatography instead of commercial RNA purification kit. In the Sephadex G-15 chromatography the major portion of RNA was eluted in the fractions ranging from 3rd to 5th whereas broad elution profile of RNA was obtained from the Sephadex G-50 chromatography. The elution profile and purity of RNA obtained from Sephadex G-15 chromatography was very similar to that by commercial RNA purification kit. Furthermore, operating time required for purification of RNA by Sephadex G-15 was rather smaller than that by commercial kit. Overall results suggest that the purification of radiolabeled RNA using Sephadex G-15 is more money and time saving than using commercial RNA purification kit

Gradient High Performance Liquid Chromatography Method ...

African Journals Online (AJOL)

Purpose: To develop a gradient high performance liquid chromatography (HPLC) method for the simultaneous determination of phenylephrine (PHE) and ibuprofen (IBU) in solid ..... nimesulide, phenylephrine. Hydrochloride, chlorpheniramine maleate and caffeine anhydrous in pharmaceutical dosage form. Acta Pol.

Carbon nanoparticles from corn stalk soot and its novel application as stationary phase of hydrophilic interaction chromatography and per aqueous liquid chromatography

International Nuclear Information System (INIS)

Li Yuanyuan; Xu Luan; Chen Tong; Liu Xiaoyan; Xu Zhigang; Zhang Haixia

2012-01-01

Highlights: ► Carbon nanoparticles (6–18 nm in size) were prepared from corn stalk soot. ► CNPs-based silica were used as novel chromatography stationary phase. ► The new phase shows good separation selectivity for polar compounds. ► The new phase had the similar retention for polar probes in HILIC and PALC modes. ► In contrast to PALC, under HILIC conditions high efficiencies were achieved. - Abstract: Carbon nanoparticles (CNPs) (6–18 nm in size) were prepared by refluxing corn stalk soot in nitric acid. The obtained acid-oxidized CNPs are soluble in water due to the existence of carboxylic and hydroxyl groups. 13 C NMR measurement shows the CNPs are mainly of sp 2 and sp 3 carbon structure different from CNPs obtained from candle soot and natural gas soot. Furthermore, these CNPs exhibit unique photoluminescence properties. Interestingly, the CNPs might be exploited to immobilize on the surface of porous silica particles as chromatographic stationary phase. The resultant packing material was evaluated by high-performance liquid chromatography, indicating that the new stationary phase could be used in hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes. The separation of five nucleosides, four sulfa compounds and safflower injection was achieved by using the new column in the HILIC and PALC modes, respectively.

Trends in the analysis of natural gas by capillary gas chromatography

NARCIS (Netherlands)

Cramers, C.A.M.G.; Rossum, van G.J.

1986-01-01

The importance of correct determination of physical and chemical properties of natural gas is evident. The calculation of calorific value or hydrocarbon dew point requires detailed analysis as can be provided by gas chromatography. Analysis by gas chromatography is a necessary complement to direct

Hyphenated and comprehensive liquid chromatography × gas chromatography-mass spectrometry for the identification of Mycobacterium tuberculosis.

Science.gov (United States)

Mourão, Marta P B; Denekamp, Ilse; Kuijper, Sjoukje; Kolk, Arend H J; Janssen, Hans-Gerd

2016-03-25

Tuberculosis is one of the world's most emerging public health problems, particularly in developing countries. Chromatography based methods have been used to tackle this epidemic by focusing on biomarker detection. Unfortunately, interferences from lipids in the sputum matrix, particularly cholesterol, adversely affect the identification and detection of the marker compounds. The present contribution describes the serial combination of normal phase liquid chromatography (NPLC) with thermally assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) to overcome the difficulties of biomarker evaluation. The in-series combination consists of an LC analysis where fractions are collected and then transferred to the THM-GC-MS system. This was either done with comprehensive coupling, transferring all the fractions, or with hyphenated interfacing, i.e. off-line multi heart-cutting, transferring only selected fractions. Owing to the high sensitivity and selectivity of LC as a sample pre-treatment method, and to the high specificity of the MS as a detector, this analytical approach, NPLC × THM-GC-MS, is extremely sensitive. The results obtained indicate that this analytical set-up is able to detect down to 1 × 10(3) mycobacteria/mL of Mycobacterium tuberculosis strain 124, spiked in blank sputum samples. It is a powerful analytical tool and also has great potential for full automation. If further studies demonstrate its usefulness when applied blind in real sputum specimens, this technique could compete with the current smear microscopy in the early diagnosis of tuberculosis. Copyright © 2015 Elsevier B.V. All rights reserved.

Affinity chromatography: A versatile technique for antibody purification.

Science.gov (United States)

Arora, Sushrut; Saxena, Vikas; Ayyar, B Vijayalakshmi

2017-03-01

Antibodies continue to be extremely utilized entities in myriad applications including basic research, imaging, targeted delivery, chromatography, diagnostics, and therapeutics. At production stage, antibodies are generally present in complex matrices and most of their intended applications necessitate purification. Antibody purification has always been a major bottleneck in downstream processing of antibodies, due to the need of high quality products and associated high costs. Over the years, extensive research has focused on finding better purification methodologies to overcome this holdup. Among a plethora of different techniques, affinity chromatography is one of the most selective, rapid and easy method for antibody purification. This review aims to provide a detailed overview on affinity chromatography and the components involved in purification. An array of support matrices along with various classes of affinity ligands detailing their underlying working principles, together with the advantages and limitations of each system in purifying different types of antibodies, accompanying recent developments and important practical methodological considerations to optimize purification procedure are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

[Analysis of microalbuminuria with immunonephelometry and high performance liquid chromatography. Evaluation of new criteria].

Science.gov (United States)

Markó, Lajos; Molnár, Gergo Attila; Wagner, Zoltán; Koszegi, Tamás; Matus, Zoltán; Mohás, Márton; Kuzma, Mónika; Szijártó, István András; Wittmann, István

2008-01-13

Hypertension as well as type 2 diabetes mellitus is a major factor in population mortality. Both diseases damage the endothelium, the early sign of which is microalbuminuria, which can be screened by dipstick and can be diagnosed by using immuno-based and high performance liquid chromatography methods. Using high performance liquid chromatography, the non-immunoreactive albumin can be detected as well. The authors aimed at the examination of albuminuria in the case of immunonephelometrically negative patients with high performance liquid chromatography, in diabetic and hypertensive and non-diabetic hypertensive populations. The authors also wanted to compare the present (albumin-creatinine ratio: male: > or =2.5 mg/mmol, female: > or =3.5 mg/mmol) and a new criteria of the Heart Outcomes Prevention Evaluation study (patients without diabetes: immunological method, > or =0.7 mg/mmol; high performance liquid chromatography, > or =3.1 mg/mmol; individuals with diabetes: immunological method, > or =1.4 mg/mmol; high performance liquid chromatography, > or =5.2 mg/mmol) of microalbuminuria. Examination of fresh urines of 469 microalbuminuria negative patients by dipstick were performed by immunonephelometry. Patients, who were microalbuminuria negative by immunonephelometry as well, were further analyzed by high performance liquid chromatography using the Accumintrade mark Kit, based on size-exclusion chromatography. Three times higher albuminuria were found with high performance liquid chromatography than with immunonephelometry. The intraindividual coefficient of variation did not differ in the two methods (37 +/- 31% vs. 40 +/- 31%, p = 0.869; immunonephelometry vs. high performance liquid chromatography; mean +/- standard deviation). Using the present criteria for microalbuminuria, 43% of immunonephelometrically negative patients proved to be microalbuminuric by high performance liquid chromatography. Using the new criteria of the Heart Outcomes Prevention

Simultaneous determination of niacin and pyridoxine at trace levels by using diode array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry.

Science.gov (United States)

Sel, Sabriye; Öztürk Er, Elif; Bakırdere, Sezgin

2017-12-01

A highly sensitive and simple diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method was developed for the simultaneous determination of niacin and pyridoxine in pharmaceutical drugs, tap water, and wastewater samples. To determine the in vivo behavior of niacin and pyridoxine, analytes were subjected to simulated gastric conditions. The calibration plots of the diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method showed good linearity over a wide concentration range with close to 1.0 correlation coefficients for both analytes. The limit of detection/limit of quantitation values for liquid chromatography quadrupole time-of-flight tandem mass spectrometry analysis were 1.98/6.59 and 1.3/4.4 μg/L for niacin and pyridoxine, respectively, while limit of detection/limit of quantitation values for niacin and pyridoxine in high-performance liquid chromatography analysis were 3.7/12.3 and 5.7/18.9 μg/L, respectively. Recovery studies were also performed to show the applicability of the developed methods, and percentage recovery values were found to be 90-105% in tap water and 94-97% in wastewater for both analytes. The method was also successfully applied for the qualitative and quantitative determination of niacin and pyridoxine in drug samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface modification of chromatography adsorbents by low temperature low pressure plasma

DEFF Research Database (Denmark)

Arpanaei, Ayyoob; Winther-Jensen, Bjørn; Theodosiou, E.

2010-01-01

In this study we show how low temperature glow discharge plasma can be used to prepare bi-layered chromatography adsorbents with non-adsorptive exteriors. The commercial strong anion exchange expanded bed chromatography matrix, Q HyperZ, was treated with plasmas in one of two general ways. Using ...

Hierarchical CaCO3 chromatography: a stationary phase based on biominerals.

Science.gov (United States)

Sato, Kosuke; Oaki, Yuya; Takahashi, Daisuke; Toshima, Kazunobu; Imai, Hiroaki

2015-03-23

In biomineralization, acidic macromolecules play important roles for the growth control of crystals through a specific interaction. Inspired by this interaction, we report on an application of the hierarchical structures in CaCO3 biominerals to a stationary phase of chromatography. The separation and purification of acidic small organic molecules are achieved by thin-layer chromatography and flash chromatography using the powder of biominerals as the stationary phase. The unit nanocrystals and their oriented assembly, the hierarchical structure, are suitable for the adsorption site of the target organic molecules and the flow path of the elution solvents, respectively. The separation mode is ascribed to the specific adsorption of the acidic molecules on the crystal face and the coordination of the functional groups to the calcium ions. The results imply that a new family of stationary phase of chromatography can be developed by the fine tuning of hierarchical structures in CaCO3 materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bacterial Cell Wall Precursor Phosphatase Assays Using Thin-layer Chromatography (TLC) and High Pressure Liquid Chromatography (HPLC).

Science.gov (United States)

Pazos, Manuel; Otten, Christian; Vollmer, Waldemar

2018-03-20

Peptidoglycan encases the bacterial cytoplasmic membrane to protect the cell from lysis due to the turgor. The final steps of peptidoglycan synthesis require a membrane-anchored substrate called lipid II, in which the peptidoglycan subunit is linked to the carrier lipid undecaprenol via a pyrophosphate moiety. Lipid II is the target of glycopeptide antibiotics and several antimicrobial peptides, and is degraded by 'attacking' enzymes involved in bacterial competition to induce lysis. Here we describe two protocols using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC), respectively, to assay the digestion of lipid II by phosphatases such as Colicin M or the LXG toxin protein TelC from Streptococcus intermedius . The TLC method can also monitor the digestion of undecaprenyl (pyro)phosphate, whereas the HPLC method allows to separate the di-, mono- or unphosphorylated disaccharide pentapeptide products of lipid II.

Purification of a 166mHo solution by successive high-performance liquid chromatography and gravitational chromatography for half-life determination

International Nuclear Information System (INIS)

Florence Gueguen; Helene Isnard; Carole Bresson; Celine Caussignac; Guillaume Stadelmann; Anthony Nonell; Sebastien Mialle; Karsten Kossert; Frederic Chartier

2014-01-01

A methodology to purify a 166m Ho solution has been developed by a combination of activity and mass concentration measurements in order to further determine the 166m Ho half-life. The isobaric interference at m/q ≃ 166 requires Ho purification from non-natural Er with a high purification degree due to the large amount of Ho as opposed to Er. The Ho/Er separation was achieved using high-performance liquid chromatography on a semi-preparative column followed by purification on gravitational chromatography. The efficiency of the separation was evaluated after precise determination of the Er isotopic composition. The purification methodology enabled to separate Ho from Er. (author)

Impact of comprehensive two-dimensional gas chromatography with mass spectrometry on food analysis.

Science.gov (United States)

Tranchida, Peter Q; Purcaro, Giorgia; Maimone, Mariarosa; Mondello, Luigi

2016-01-01

Comprehensive two-dimensional gas chromatography with mass spectrometry has been on the separation-science scene for about 15 years. This three-dimensional method has made a great positive impact on various fields of research, and among these that related to food analysis is certainly at the forefront. The present critical review is based on the use of comprehensive two-dimensional gas chromatography with mass spectrometry in the untargeted (general qualitative profiling and fingerprinting) and targeted analysis of food volatiles; attention is focused not only on its potential in such applications, but also on how recent advances in comprehensive two-dimensional gas chromatography with mass spectrometry will potentially be important for food analysis. Additionally, emphasis is devoted to the many instances in which straightforward gas chromatography with mass spectrometry is a sufficiently-powerful analytical tool. Finally, possible future scenarios in the comprehensive two-dimensional gas chromatography with mass spectrometry food analysis field are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supercritical fluid chromatography approach for a sustainable manufacture of new stereoisomeric anticancer agent.

Science.gov (United States)

Ghinet, Alina; Zehani, Yasmine; Lipka, Emmanuelle

2017-10-25

Two routes aimed at the manufacture of unprecedented stereoisomeric combretastatin A-4 analogue were described: flash chromatography vs supercritical fluid chromatography. The latter has many advantages over liquid chromatography and was therefore chosen for the small scale separation of methyl 1-[(3-hydroxy-4-methoxyphenyl) (3,4,5-trimethoxyphenyl)methyl]-5-oxo-l-prolinate 5, with potential antitumoral activity. After a screening of six different polysaccharide based chiral stationary phases and four co-solvents, the percentage of co-solvent, the flow-rate and the outlet pressure were optimized through a design of experiments (DoE). The preparation of 50mg of each stereoisomer was achieved successfully on a Chiralpak AD-H with isopropanol as a co-solvent. Productivity (kkd), solvent usage and environmental factor (E Factor) were calculated. Flash chromatography and supercritical fluid chromatography approaches were compared in terms of yield and purity of each stereoisomer manufactured. Copyright © 2017 Elsevier B.V. All rights reserved.

Prüfungen zur Beurteilung der Brandgefahr; Beispiele für Verfahren zur Beurteilung einer Brandgefahr und für die Auslegung von Ergebnissen; 3.1: Kennwerte der Verbrennung und Übersicht über Prüfverfahren zu ihrer Ermittlung; Identisch mit IEC 60695-3-1, Ausgabe 1982

CERN Document Server

Deutsches Institut für Normung. Berlin

1986-01-01

Prüfungen zur Beurteilung der Brandgefahr; Beispiele für Verfahren zur Beurteilung einer Brandgefahr und für die Auslegung von Ergebnissen; 3.1: Kennwerte der Verbrennung und Übersicht über Prüfverfahren zu ihrer Ermittlung; Identisch mit IEC 60695-3-1, Ausgabe 1982

Liquid chromatography in migration studies

International Nuclear Information System (INIS)

Carlsen, L.; Batsberg, W.

1982-01-01

Liquid chromatography ahs been suggested as a facile experimental technique to determine important physico-chemical properties, as permeability, porosity, dispersion-, diffusion-, and sorption charcteristics for geological material as chalk samples. The feasibility of the trechnique as a rapid method to evaluate the possible influence of changes in ground water composition on the migration behavior of radionuclides has been demonstrated

Undergraduate Separations Utilizing Flash Chromatography

Science.gov (United States)

Horowitz, G.

2000-02-01

This article describes the procedures used to carry out four flash chromatography experiments: the isolation of the carotenes, chlorophylls and xanthophylls from a spinach extract; the separation of ß-carotene from tetraphenyl cyclopentadienone; the isolation of (+) and (-) carvone from caraway and spearmint oil; and the purification of benzil from benzoin. Apparatus used is nonbreakable, easy to use, and inexpensive.

The Purification of a Blood Group A Glycoprotein: An Affinity Chromatography Experiment.

Science.gov (United States)

Estelrich, J.; Pouplana, R.

1988-01-01

Describes a purification process through affinity chromatography necessary to obtain specific blood group glycoproteins from erythrocytic membranes. Discusses the preparation of erythrocytic membranes, extraction of glycoprotein from membranes, affinity chromatography purification, determination of glycoproteins, and results. (CW)

Microcystin Detection Characteristics of Fluorescence Immunochromatography and High Performance Liquid Chromatography

International Nuclear Information System (INIS)

Pyo, Dong Jin; Park, Geun Young; Choi, Jong Chon; Oh, Chang Suk

2005-01-01

Different detection characteristics of fluorescence immunochromatography method and high performance liquid chromatography (HPLC) method for the analysis of cyanobacterial toxins were studied. In particular, low and high limits of detection, detection time and reproducibility and detectable microcystin species were compared when fluorescence immunochromatography method and high performance liquid chromatography method were applied for the detection of microcystin (MC), a cyclic peptide toxin of the freshwater cyanobacterium Microcystis aeruginosa. A Fluorescence immunochromatography assay system has the unique advantages of short detection time and low detection limit, and high performance liquid chromatography detection method has the strong advantage of individual quantifications of several species of microcystins

High-Performance Liquid Chromatography-Mass Spectrometry.

Science.gov (United States)

Vestal, Marvin L.

1984-01-01

Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

Intercomparison of the measurements of oxalic acid in aerosols by gas chromatography and ion chromatography

Science.gov (United States)

Kawamura, Kimitaka; Barrie, Leonard A.; Toom-Sauntry, Desiree

2010-12-01

Oxalate, the anion of oxalic acid, is one of the most abundant measurable organic species in atmospheric aerosols. Traditionally, this bifunctional species has been measured by gas chromatography (GC) after derivatization to butyl ester and by ion chromatography (IC) without derivatization. However, there are few published comparisons of the two techniques. Here, we report the results of an intercomparison study for the measurement of oxalic acid in Arctic aerosols (oxalic acid by GC ranged from 6.5-59.1 ng m -3 (av. 26.0 ng m -3, median 26.2 ng m -3) whereas those by IC ranged from 6.6-52.1 ng m -3 (av. 26.6 ng m -3, median 25.4 ng m -3). They showed a good correlation ( r = 0.84) with a slope of 0.96. Thus, observations of oxalate obtained by GC employing dibutyl esters are almost equal to those by IC. Because the accuracy of oxalic acid by GC method largely depends on the method used, it is important to strictly examine the recovery in each study.

Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

African Journals Online (AJOL)

HP

Original Research Article. Gas Chromatography-Mass Spectrometric Analysis and ... into a natural fumigant/insecticide for the control of stored product insects. Keywords: Mallotus ..... stability as well as reduce cost. ACKNOWLEDGEMENT.

Boron isotopic enrichment by displacement chromatography

International Nuclear Information System (INIS)

Mohapatra, K.K.; Bose, Arun

2014-01-01

10 B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10 B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH) 4 - ) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10 B and 11 B

Development of an on-line mixed-mode gel liquid chromatography×reversed phase liquid chromatography method for separation of water extract from Flos Carthami.

Science.gov (United States)

Wang, Yu-Qing; Tang, Xu; Li, Jia-Fu; Wu, Yun-Long; Sun, Yu-Ying; Fang, Mei-Juan; Wu, Zhen; Wang, Xiu-Min; Qiu, Ying-Kun

2017-10-13

A novel on-line comprehensive two-dimensional liquid chromatography (2D-LC) method by coupling mixed-mode gel liquid chromatography (MMG-LC) with reversed phase liquid chromatography (RPLC) was developed. A mixture of 17 reference compounds was used to study the separation mechanism. A crude water extract of Flos Carthami was applied to evaluate the performance of the novel 2D-LC system. In the first dimension, the extract was eluted with a gradient of water/methanol over a cross-linked dextran gel Sephadex LH-20 column. Meanwhile, the advantages of size exclusion, reversed phase partition and adsorption separation mechanism were exploited before further on-line reversed phase purification on the second dimension. This novel on-line mixed-mode Sephadex LH-20×RPLC method provided higher peak resolution, sample processing ability (2.5mg) and better orthogonality (72.9%) versus RPLC×RPLC and hydrophilic interaction liquid chromatography (HILIC)×RPLC. To the best of our knowledge, this is the first report of a mixed-mode Sephadex LH-20×RPLC separation method with successful applications in on-line mode, which might be beneficial for harvesting targets from complicated medicinal plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Exploration of overloaded cation exchange chromatography for monoclonal antibody purification.

Science.gov (United States)

Liu, Hui F; McCooey, Beth; Duarte, Tiago; Myers, Deanna E; Hudson, Terry; Amanullah, Ashraf; van Reis, Robert; Kelley, Brian D

2011-09-28

Cation exchange chromatography using conventional resins, having either diffusive or perfusive flow paths, operated in bind-elute mode has been commonly employed in monoclonal antibody (MAb) purification processes. In this study, the performance of diffusive and perfusive cation exchange resins (SP-Sepharose FF (SPSFF) and Poros 50HS) and a convective cation exchange membrane (Mustang S) and monolith (SO(3) Monolith) were compared. All matrices were utilized in an isocratic state under typical binding conditions with an antibody load of up to 1000 g/L of chromatographic matrix. The dynamic binding capacity of the cation exchange resins is typically below 100 g/L resin, so they were loaded beyond the point of anticipated MAb break through. All of the matrices performed similarly in that they effectively retained host cell protein and DNA during the loading and wash steps, while antibody flowed through each matrix after its dynamic binding capacity was reached. The matrices differed, though, in that conventional diffusive and perfusive chromatographic resins (SPSFF and Poros 50HS) demonstrated a higher binding capacity for high molecular weight species (HMW) than convective flow matrices (membrane and monolith); Poros 50HS displayed the highest HMW binding capacity. Further exploration of the conventional chromatographic resins in an isocratic overloaded mode demonstrated that the impurity binding capacity was well maintained on Poros 50HS, but not on SPSFF, when the operating flow rate was as high as 36 column volumes per hour. Host cell protein and HMW removal by Poros 50HS was affected by altering the loading conductivity. A higher percentage of host cell protein removal was achieved at a low conductivity of 3 mS/cm. HMW binding capacity was optimized at 5 mS/cm. Our data from runs on Poros 50HS resin also showed that leached protein A and cell culture additive such as gentamicin were able to be removed under the isocratic overloaded condition. Lastly, a MAb

Application of ion chromatography in clinical studies and pharmaceutical industry.

Science.gov (United States)

Michalski, Rajmund

2014-01-01

Ion chromatography is a well-established regulatory method for analyzing anions and cations in environmental, food and many other samples. It offers an enormous range of possibilities for selecting stationary and mobile phases. Additionally, it usually helps to solve various separation problems, particularly when it is combined with different detection techniques. Ion chromatography can also be used to determine many ions and substances in clinical and pharmaceutical samples. It provides: availability of high capacity stationary phases and sensitive detectors; simple sample preparation; avoidance of hazardous chemicals; decreased sample volumes; flexible reaction options on a changing sample matrix to be analyzed; or the option to operate a fully-automated system. This paper provides a short review of the ion chromatography applications for determining different inorganic and organic substances in clinical and pharmaceutical samples.

State-of-the art of selective detection and identification of I-, Br-, Cl-, and F-containing compounds in gas chromatography and liquid chromatography.

Science.gov (United States)

Brede, Cato; Pedersen-Bjergaard, Stig

2004-09-24

This review article presents an overview of halogen-specific detection in gas chromatography (GC) and liquid chromatography (LC). Attention is primarily focused on the use of plasma emission spectroscopy and plasma mass spectrometry as detectors, but other halogen-selective detection principles are also mentioned. Different instrumental configurations are discussed both with respect to technical set-up and performance, the principal reasons for halogen-selective detection are highlighted, and recent applications are reviewed from areas such as environmental chemistry, petroleum characterization, and drug analysis.

Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

Science.gov (United States)

Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

2015-02-01

Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiochemical purity determination by paper chromatography 2

International Nuclear Information System (INIS)

1975-01-01

The standard relates to the determination of radiochemical impurities in labelled compounds using paper chromatography. The basic terms are given as is the description of procedure and evaluation of chromatograms. (E.S.)

Gas Chromatography-Mass Spectrometric Analysis of Nematicidal ...

African Journals Online (AJOL)

Gas Chromatography-Mass Spectrometric Analysis of Nematicidal Essential Oil of Valeriana ... Tropical Journal of Pharmaceutical Research ... have a potential to be developed to natural nematicides for the control of cereal cyst nematodes.

Comparison of different transition metal ions for immobilized metal affinity chromatography of selenoprotein P from human plasma

DEFF Research Database (Denmark)

Sidenius, U; Farver, O; Jøns, O

1999-01-01

Cu2+, Ni2+, Zn2+, Co2+ and Cd2+ were evaluated in metal ion affinity chromatography for enrichment of selenoprotein P, and immobilized Co2+ affinity chromatography was found to be the most selective chromatographic method. The chromatography was performed by fast protein liquid chromatography...

Potential application of gas chromatography to the analysis of hydrogen isotopes

International Nuclear Information System (INIS)

Warner, D.K.; Sprague, R.E.; Bohl, D.R.

1976-01-01

Gas chromatography is used at Mound Laboratory for the analysis of hydrogen isotopic impurities in gas mixtures. This instrumentation was used to study the applicability of the gas chromatography technique to the determination of the major components of hydrogen isotopic gas mixtures. The results of this study, including chromatograms and precision data, are presented

Überzeugen, Stupsen, Zwingen – Die Konzeption von Nudge und Libertärem Paternalismus und ihr Verhältnis zu anderen Formen der Verhaltenssteuerung

Directory of Open Access Journals (Sweden)

Düber Dominik

2016-07-01

Full Text Available Trotz der überwältigenden öffentlichen wie wissenschaftlichen Resonanz, auf die der Nudge-Ansatz von Thaler und Sunstein gestoßen ist, bleiben die genauen Konturen dieses Theorie und Policyvorschlages unscharf. So ist an vielen Stellen unklar, worin die spezifische Differenz gegenüber klassischen Formen der Verhaltenssteuerung liegen soll. Für eine Bewertung des Ansatzes in seinen Vorzügen und Nachteilen gegenüber klassischen Steuerungsformen ist eine solche klärende Einordnung jedoch notwendige Vorbedingung. Der Aufsatz arbeitet daher die bestehenden Definitions- und Abgrenzungsprobleme von „Nudge“ und „Libertärem Paternalismus“ heraus und plädiert sodann für einen Kernbegriff von „Nudge“, der dessen Extension einschränkt, um ihn als originären und eigenständigen Vorschlag einzugrenzen. Ein so präzisiertes Verständnis von Nudge wird dann hinsichtlich seiner Eigenschaften sowie der Gemeinsamkeiten und Unterschiede zu klassischen Formen der Verhaltenssteuerung ins Verhältnis gesetzt.

Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

African Journals Online (AJOL)

Tropical Journal of Pharmaceutical Research ... apelta aerial parts was analyzed by gas chromatography/mass spectrometric (GC/MS) to determine its composition. ... into a natural fumigant/insecticide for the control of stored product insects.

Identification of Cyclopentenyl Fatty Acids by Gas Liquid Chromatography and Mass Spectrometry

DEFF Research Database (Denmark)

Shukla, V. K. S.; Abdel-Moety, E. M.; Larsen, Elfinn

1979-01-01

The straight chain fatty acids and the cyclopentenyl fatty acids present in the lipids of Hydnocarpus wightiana seeds were separated as their pyrrolidides by means of gas chromatography. A gas chromatography-mass spectrometry system confirmed the complete separation and permitted the identification...

Early stages in the history of gas chromatography.

Science.gov (United States)

Kolomnikov, Ivan G; Efremov, Alexander M; Tikhomirova, Tatyana I; Sorokina, Nadezhda M; Zolotov, Yury A

2018-02-16

The creation of gas chromatography is traditionally associated with the names of Nobel Prize winner Archer Martin and his colleagues Richard Synge and Anthony James. However, sometimes references to their predecessors can be found. An investigation conducted by the authors of this article not only confirmed the reliability of these references; but in fact led to the conclusion that by 1952, which is commonly believed to be the year when gas chromatography was born, many research papers had already been devoted to this method, mainly, in its gas-solid version. These papers are considered in this article. Copyright © 2018. Published by Elsevier B.V.

Column liquid chromatography applied to concentrating, separating, and determining platinum metals

International Nuclear Information System (INIS)

Alimarin, I.P.; Basova, E.M.; Bol'shova, T.A.; Ivanov, V.M.

1986-01-01

The present survey deals with high-performance liquid chromatography (HPLC) in relation to the chromatographic behavior of the platinum metals, including separation and determination. The data shows that HPLC is the most promising and effective method of separating metals, including platinum ones. The method provides efficient separation of microgram amoounts of mixtures with a resolving power 3-20 times that of thin-layer chromatography. It is shown that the most promising line of advance in HPLC for inorganic systems lies in the separation and determination of metals as chelates by absorption or ion-pair chromatography. Examples of using HPLC for determining noble metals in particular cases indicate that the metrological characteristics are favorable

Ion exclusion chromatography for the purification of L-glutamine; Ion haijo chromatography ni yoru L-glutamine no seiseiho no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Ito, H.; Nishi, A.; Naruse, M. [Ajinomoto Co. Inc., Kawasaki (Japan)

1998-09-05

Ion exclusion chromatography for the purification of L-glutamine is studied. L-glutamine is usually produced by fermentation and used in pharmaceuticals. By using a model solution of L-glutamine and L-glutamic acid, the optimum cation exchange resin is examined. As a result of the experiments, it is found that a cation exchange resin which has smaller crosslinkage and smaller diameter is better. Ammonium sulfate, L-glutamic acid and pyrrolidonecarboxylic acid, which are usually contained in fermentation broth as impurities, are effectively separated by this method. Moreover, the experimental data of the chromatography is expressed fairly well by the differential equations which express the mass transfer in the fixed bed. 8 refs., 5 figs., 2 tabs.

Analysis of short-chain acids from anaerobic bacteria by high-performance liquid chromatography.

OpenAIRE

Guerrant, G O; Lambert, M A; Moss, C W

1982-01-01

A standard mixture of 25 short-chain fatty acids was resolved by high-performance liquid chromatography, using an Aminex HPX-87 column. The acids produced in culture media by anaerobic bacteria were analyzed by high-performance liquid chromatography after extraction with ether and reextraction into a small volume of 0.1 N NaOH. The presence of fumaric acid in culture extracts of Peptostreptococcus anaerobius was confirmed by gas chromatography-mass spectrometry analysis of the trapped eluent ...

Triticonazole enantiomers: Separation by supercritical fluid chromatography and the effect of the chromatographic conditions.

Science.gov (United States)

He, Jianfeng; Fan, Jun; Yan, Yilun; Chen, Xiaodong; Wang, Tai; Zhang, Yaomou; Zhang, Weiguang

2016-11-01

Enantiomeric pairs of triticonazole have been successfully separated by supercritical fluid chromatography coupled with a tris(3,5-dimethylphenylcarbamoyl) cellulose-coated chiral stationary phase in this work. The effects of co-solvent, dissolution solvent, flow rate, backpressure, and column temperature have been studied in detail with respect to retention, selectivity, and resolution of triticonazole. As indicated, the co-solvents mostly affected the retention factors and resolution, due to the different molecular structure and polarity. In addition, the dissolution solvents, namely, chloromethanes and alcohols, have been also important for enantioseparation because of the different interaction with stationary phase. Higher flow rate and backpressure led to faster elution of the triticonazole molecules, and the change of column temperature showed slight effect on the resolution of triticonazole racemate. Moreover, a comparative separation experiment between supercritical fluid chromatography and high performance liquid chromatography revealed that chiral supercritical fluid chromatography gave the 3.5 times value of R s /t R2 than high performance liquid chromatography, which demonstrated that supercritical fluid chromatography had much higher separation efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trends in data processing of comprehensive two-dimensional chromatography: state of the art.

Science.gov (United States)

Matos, João T V; Duarte, Regina M B O; Duarte, Armando C

2012-12-01

The operation of advanced chromatographic systems, namely comprehensive two-dimensional (2D) chromatography coupled to multidimensional detectors, allows achieving a great deal of data that need special care to be processed in order to characterize and quantify as much as possible the analytes under study. The aim of this review is to identify the main trends, research needs and gaps on the techniques for data processing of multidimensional data sets obtained from comprehensive 2D chromatography. The following topics have been identified as the most promising for new developments in the near future: data acquisition and handling, peak detection and quantification, measurement of overlapping of 2D peaks, and data analysis software for 2D chromatography. The rational supporting most of the data processing techniques is based on the generalization of one-dimensional (1D) chromatography although algorithms, such as the inverted watershed algorithm, use the 2D chromatographic data as such. However, for processing more complex N-way data there is a need for using more sophisticated techniques. Apart from using other concepts from 1D chromatography, which have not been tested for 2D chromatography, there is still room for new improvements and developments in algorithms and software for dealing with 2D comprehensive chromatographic data. Copyright © 2012 Elsevier B.V. All rights reserved.

Forced-flow chromatography of rare earths using sensitive spectrophometry

International Nuclear Information System (INIS)

Matsui, Masakazu; Aoki, Toru; Kumagai, Tetsu.

1981-01-01

The sensitive spectrophotometric method for the rare earth elements with xylenol orange in the presence of cetylpyridinium bromide was applied to the continuous detection system of liquid chromatography. Fourteen rare earth elements were completely separated within 130 min cation-exchange chromatography using 2-hydroxy-iso-butylic acid. The eluted ions were determined with absorption maxima of their complexes at around 610 nm. A linear relationship between the peak height and the amounts of rare earth elements was also obtained over the range 0.04 to 0.5 MU g. (author)

Study of comportment of trioctylphosphine oxide by coat slight chromatography

International Nuclear Information System (INIS)

Meddour, Laaldja; Azzouz Abdelkrim

1996-04-01

The synthesis and characterisation process of the extractant agent 'Trioctylphosphine oxide' (TOPO) are not very developped in the literature. However, in order to identify this agent (TOPO) in its synthesis process, we attempt several analysis methods. The coat slight chromatography proves the simple and accessible method, that explains the choice of this study. In the present work, we have analysed the TOPO by coat slight chromatography with the intention of finding a better solvent

Hyphenated techniques in multidimensional gas chromatography for analysis of wine aroma and related odorants

OpenAIRE

Chin, Sung Tong

2017-01-01

The advent of analytical multidimensional gas chromatography (MDGC) techniques, with recent development in comprehensive two-dimensional gas chromatography (GC×GC) as well as microfluidic technology in conventional heart-cut MDGC, has achieved excellent separation efficiency for advanced characterization of complex volatile and semi-volatile samples, which is unlikely to be accomplished by single dimensional chromatography. This dissertation work has highlighted the potential opportunities fo...

Electronic spectral detection in liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Biggs, Wilton R. [ChevronTexaco Chemical Co., P. O. Box 1627, Richmond, CA 94802 (United States); Fetzer, John C. [Fetzpahs Consulting, 1283 Santa Fe St., Hercules, CA 94547 (United States)

2002-07-01

The use of absorbance and fluorescence spectrometers as liquid chromatography detectors is described. These detectors offer sensitive detection that can also identify the peaks in a chromatogram. Many examples, mainly from the separation of polycyclic aromatic hydrocarbons, are given that show the selectivity and usefulness of these detectors. (orig.)

Analytical biotechnology: Capillary electrophoresis and chromatography

International Nuclear Information System (INIS)

Horvath, C.; Nikelly, J.G.

1990-01-01

The papers describe the separation, characterization, and equipment required for the electrophoresis or chromatography of cyclic nucleotides, pharmaceuticals, therapeutic proteins, recombinant DNA products, pheromones, peptides, and other biological materials. One paper, On-column radioisotope detection for capillary electrophoresis, has been indexed separately for inclusion on the data base

Size-exclusion chromatography for the determination of the boiling point distribution of high-boiling petroleum fractions.

Science.gov (United States)

Boczkaj, Grzegorz; Przyjazny, Andrzej; Kamiński, Marian

2015-03-01

The paper describes a new procedure for the determination of boiling point distribution of high-boiling petroleum fractions using size-exclusion chromatography with refractive index detection. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with flame ionization detection. This study revealed that in spite of substantial differences in the separation mechanism and the detection mode, the size-exclusion chromatography technique yields similar results for the determination of boiling point distribution compared with simulated distillation and novel empty column gas chromatography. The developed procedure using size-exclusion chromatography has a substantial applicability, especially for the determination of exact final boiling point values for high-boiling mixtures, for which a standard high-temperature simulated distillation would have to be used. In this case, the precision of final boiling point determination is low due to the high final temperatures of the gas chromatograph oven and an insufficient thermal stability of both the gas chromatography stationary phase and the sample. Additionally, the use of high-performance liquid chromatography detectors more sensitive than refractive index detection allows a lower detection limit for high-molar-mass aromatic compounds, and thus increases the sensitivity of final boiling point determination. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Column chromatography isolation of nicotine from tobacco leaf extract (Nicotiana tabaccum L.)

Science.gov (United States)

Fathi, Raden Muhammad; Fauzantoro, Ahmad; Rahman, Siti Fauziyah; Gozan, Misri

2018-02-01

Restrictions on the use of dried tobacco leaf for cigarette production must be accompanied by the development of non-cigarette alternative products that are made from tobacco leaves. One of the alternative that can be done is to use the nicotine compound in tobacco leaf extract as medical product, such as Parkinson's medication or to be used as active substance in biopesticide. Nicotine was isolated using column chromatography method with the variation of mobile phase mixture ratio (petroleum ether and ethanol), started from 8:2, 6:4, 4:6, 2:8, to 0:10. All of the chromatographic fraction from each mobile phase's ratio was then tested qualitatively using thin layer chromatography (TLC) and also quantitatively using HPLC instrument. The column chromatography process could isolate 4.006% of nicotine compound from 4.19% tobacco leaf extract's nicotine. It is also known that ethanol is a good solution to be used as chromatography's mobile phase for nicotine isolation from tobacco leaf extract.

Advances in silver ion chromatography for the analysis of fatty acids and triacylglycerols-2001 to 2011.

Science.gov (United States)

Momchilova, Svetlana M; Nikolova-Damyanova, Boryana M

2012-01-01

An effort is made to critically present the achievements in silver ion chromatography during the last decade. Novelties in columns, mobile-phase compositions and detectors are described. Recent applications of silver ion chromatography in the analysis of fatty acids and triacylglycerols are presented while stressing novel analytical strategies or new objects. The tendencies in the application of the method in complementary ways with reversed-phase chromatography, chiral chromatography and, especially, mass detection are outlined.

Pressurized planar electrochromatography, high-performance thin-layer chromatography and high-performance liquid chromatography--comparison of performance.

Science.gov (United States)

Płocharz, Paweł; Klimek-Turek, Anna; Dzido, Tadeusz H

2010-07-16

Kinetic performance, measured by plate height, of High-Performance Thin-Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Pressurized Planar Electrochromatography (PPEC) was compared for the systems with adsorbent of the HPTLC RP18W plate from Merck as the stationary phase and the mobile phase composed of acetonitrile and buffer solution. The HPLC column was packed with the adsorbent, which was scrapped from the chromatographic plate mentioned. An additional HPLC column was also packed with adsorbent of 5 microm particle diameter, C18 type silica based (LiChrosorb RP-18 from Merck). The dependence of plate height of both HPLC and PPEC separating systems on flow velocity of the mobile phase and on migration distance of the mobile phase in TLC system was presented applying test solute (prednisolone succinate). The highest performance, amongst systems investigated, was obtained for the PPEC system. The separation efficiency of the systems investigated in the paper was additionally confirmed by the separation of test component mixture composed of six hormones. 2010 Elsevier B.V. All rights reserved.

Application of gas chromatography to analysis of spirit-based alcoholic beverages.

Science.gov (United States)

Wiśniewska, Paulina; Śliwińska, Magdalena; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek

2015-01-01

Spirit-based beverages are alcoholic drinks; their production processes are dependent on the type and origin of raw materials. The composition of this complex matrix is difficult to analyze, and scientists commonly choose gas chromatography techniques for this reason. With a wide selection of extraction methods and detectors it is possible to provide qualitative and quantitative analysis for many chemical compounds with various functional groups. This article describes different types of gas chromatography techniques and their most commonly used associated extraction techniques (e.g., LLE, SPME, SPE, SFE, and SBME) and detectors (MS, TOFMS, FID, ECD, NPD, AED, O or EPD). Additionally, brief characteristics of internationally popular spirit-based beverages and application of gas chromatography to the analysis of selected alcoholic drinks are presented.

Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

Science.gov (United States)

O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

2009-01-01

Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

Instrument platforms for nano liquid chromatography

Czech Academy of Sciences Publication Activity Database

Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

2015-01-01

Roč. 1421, NOV (2015), s. 2-17 ISSN 0021-9673 R&D Projects: GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : nano liquid chromatography * splitless gradient generation * nano LC platforms Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.926, year: 2015 http://hdl.handle.net/11104/0250900

Bibliography of extraction chromatography, ch. 15

International Nuclear Information System (INIS)

Eschrich, H.; Drent, W.

1975-01-01

A bibliography of reviews, books and publications dealing with laminar extraction chromatography is given. A tabular survey of experimental data on column extraction chromatographic investigations, stationary phases and support materials is presented. An author index and corporative author index are included. This bibliography refers to various publications relevant to nuclear interest

Enrichment and Determination of radionuclides by ion chromatography

International Nuclear Information System (INIS)

ZAFIMANJATO, J.L.R.

1996-01-01

The fundamentals of Ion Chromatography (IC) and Liquid Scintillation Counting (LSC) are reviewed. Ion Chromatography as separation method for cations is coupled with Liquid Scintillation Counting for the determination of Radionuclides in water samples. An experimental arrangement for investigations on the applicability of guard columns for cationic radionuclide enrichment is shown. The saturation behaviour of single and bivalentic cations and their combination is presented. Our results show that radioactive bivalentic cations like strontium-90 and radium-226 are enriched on a Ion Pac CG 12 Dionex guard column from 100 to 300ml natural water in one single step. The procedure is suitable for their determination in concentrations down to 10 -2 Bq.l -1 [fr

Nanomaterials as stationary phases and supports in liquid chromatography.

Science.gov (United States)

Beeram, Sandya R; Rodriguez, Elliott; Doddavenkatanna, Suresh; Li, Zhao; Pekarek, Allegra; Peev, Darin; Goerl, Kathryn; Trovato, Gianfranco; Hofmann, Tino; Hage, David S

2017-10-01

The development of various nanomaterials over the last few decades has led to many applications for these materials in liquid chromatography (LC). This review will look at the types of nanomaterials that have been incorporated into LC systems and the applications that have been explored for such systems. A number of carbon-based nanomaterials and inorganic nanomaterials have been considered for use in LC, ranging from carbon nanotubes, fullerenes and nanodiamonds to metal nanoparticles and nanostructures based on silica, alumina, zirconia and titanium dioxide. Many ways have been described for incorporating these nanomaterials into LC systems. These methods have included covalent immobilization, adsorption, entrapment, and the synthesis or direct development of nanomaterials as part of a chromatographic support. Nanomaterials have been used in many types of LC. These applications have included the reversed-phase, normal-phase, ion-exchange, and affinity modes of LC, as well as related methods such as chiral separations, ion-pair chromatography and hydrophilic interaction liquid chromatography. Both small and large analytes (e.g., dyes, drugs, amino acids, peptides and proteins) have been used to evaluate possible applications for these nanomaterial-based methods. The use of nanomaterials in columns, capillaries and planar chromatography has been considered as part of these efforts. Potential advantages of nanomaterials in these applications have included their good chemical and physical stabilities, the variety of interactions many nanomaterials can have with analytes, and their unique retention properties in some separation formats. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Strong Cation Exchange Chromatography in Analysis of Posttranslational Modifications: Innovations and Perspectives

Science.gov (United States)

Edelmann, Mariola J.

2011-01-01

Strong cation exchange (SCX) chromatography has been utilized as an excellent separation technique that can be combined with reversed-phase (RP) chromatography, which is frequently used in peptide mass spectrometry. Although SCX is valuable as the second component of such two-dimensional separation methods, its application goes far beyond efficient fractionation of complex peptide mixtures. Here I describe how SCX facilitates mapping of the protein posttranslational modifications (PTMs), specifically phosphorylation and N-terminal acetylation. The SCX chromatography has been mainly used for enrichment of these two PTMs, but it might also be beneficial for high-throughput analysis of other modifications that alter the net charge of a peptide. PMID:22174558

UHPLC: The Greening Face of Liquid Chromatography.

Science.gov (United States)

Cielecka-Piontek, Judyta; Zalewski, Przemysław; Jelińska, Anna; Garbacki, Piotr

2013-01-01

Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) has been frequently proposed as an alternative to HPLC, which means introducing an environment-friendly approach to drug analysis achieved by reducing the consumption of solvents. It also offers greater chromatographic resolution and higher sensitivity as well as requiring less time due to faster analysis. This review focuses on the basics of UHPLC, compares that technique with HPLC and discusses the possibilities of applying UHPLC for the analysis of different pharmaceuticals and biopharmaceuticals.

Homochiral metal-organic frameworks and their application in chromatography enantioseparations.

Science.gov (United States)

Peluso, Paola; Mamane, Victor; Cossu, Sergio

2014-10-10

The last frontier in the chiral stationary phases (CSPs) field for chromatography enantioseparations is represented by homochiral metal-organic frameworks (MOFs), a class of organic-inorganic hybrid materials built from metal-connecting nodes and organic-bridging ligands. The modular nature of these materials allows to design focused structures by combining properly metal, organic ligands and rigid polytopic spacers. Intriguingly, chiral ligands introduce molecular chirality in the MOF-network as well as homochirality in the secondary structure of materials (such as homohelicity) producing homochiral nets in a manner mimicking biopolymers (proteins, polysaccharides) which are characterized by a definite helical sense associated with the chirality of their building blocks (amino acids or sugars). Nowadays, robust and flexible materials characterized by high porosity and surface area became available by using preparative procedures typical of the so-called reticular synthesis. This review focuses on recent developments in the synthesis and applications of homochiral MOFs as supports for chromatography enantioseparations. Indeed, despite this field is in its infancy, interesting results have been produced and a critical overview of the 12 reported applications for gas chromatography (GC) and high-performance liquid chromatography (HPLC) can orient the reader approaching the field. Mechanistic aspects are shortly discussed and a view regarding future trends in this field is provided. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparative study of radio gas-chromatography and gas chromatography - mass spectrometry coupling in the identification of metabolites of estrogens and progesterone

International Nuclear Information System (INIS)

Adessi, G.; Nhuan, T.Q.; Jayle, M.F.

1978-01-01

Radio-gas chromatography (RGC) and gas chromatography-mass spectrometry (GC-MS) were used to identify estrogen and progesterone metabolites. The RGC enables the identification of metabolites of labelled precursors ( 3 H)-estradiol-17β and ( 14 C)-progesterone were used as precursors. The GC-MS analytical technique with mass fragmentography, offers the interest of using unlabelled precursors at physiological levels. The identification of metabolites was based on obtaining the mass spectrum or the compiled fragmentogram on the basis of the most characteristic fragment ions. More over, several metabolites can be quantified on the same fragmentogram. Results on the metabolism of estradiol-17β and progesterone by the hepatic tissue of guinea pigs are given. (Auth.)

Proceedings of the DAE-BRNS theme meeting on ion chromatography separations - state of art and perspectives

International Nuclear Information System (INIS)

Jeyakumar, S.; Ramakumar, K.L.

2012-01-01

Ion Chromatography (IC) plays a vital role in all disciplines of science and technology. In the field of trace separations and speciation studies, use of IC techniques becomes indispensable. In nuclear technology, IC plays a pivotal role in the reactor water chemistry, in the front end of fuel cycle especially in the characterization of nuclear materials including the reactor fuels, post irradiation examination, actinide speciation studies and in understanding the interaction and migration of actinide species in the geo environment. Ion chromatography is also useful in the studies related to waste management particularly for the separation and determination of fission products. The aim of this meeting is to provide a forum to all the researchers in the area of ion chromatography to discuss their recent findings and information, to learn from the mutual experiences and interests, and to promote cooperation both nationally and internationally. Ion chromatography techniques including Ion Chromatography Separations and Nuclear Materials, Speciation Studies by Ion chromatography, Hyphenated -IC Techniques, Reactor Water Chemistry and Ion Chromatography, Solid Phase Extraction and Sample Preparations for IC and Separation of Bio-molecules and Environmental aspects etc are discussed. Papers relevant to INIS are indexed separately

The isotope separation by ion exchange chromatography. Application to the lithium isotopes separation; La separation isotopique par chromatographie ionique

Energy Technology Data Exchange (ETDEWEB)

Albert, M G; Barre, Y; Neige, R

1994-12-31

In this work is described the used study step to demonstrate the industrial feasibility of a lithium isotopes separation process by ion exchange chromatography. After having recalled how is carried out the exchange reaction between the lithium isotopes bound on the cations exchanger resin and those which are in solution and gave the ion exchange chromatography principle, the authors establish a model which takes into account the cascade theory already used for enriched uranium production. The size parameters of this model are: the isotopic separation factor (which depends for lithium of the ligands nature and of the coordination factor), the isotopic exchange kinetics and the mass flow (which depends of the temperature, the lithium concentration, the resins diameter and the front advance). The way they have to be optimized and the implementation of the industrial process are given. (O.M.). 5 refs.

Microbial metabolomics with gas chromatography/mass spectrometry

NARCIS (Netherlands)

Koek, M.M.; Muilwijk, B.; Werf, M.J. van der; Hankemeier, T.

2006-01-01

An analytical method was set up suitable for the analysis of microbial metabolomes, consisting of an oximation and silylation derivatization reaction and subsequent analysis by gas chromatography coupled to mass spectrometry. Microbial matrixes contain many compounds that potentially interfere with

Alternatives to Chromatography in Plant Breeding

Directory of Open Access Journals (Sweden)

Keusgen, Michael

2016-07-01

Full Text Available Wild plants were taken into cultivation because of special features. Usually, medicinal plants or spices show distinct secondary metabolites combined with a specific pattern of these compounds. Typically, chromatographic methods like gas chromatography (GC or high performance liquid chromatography (HPLC were applied as standard methods for a meaningful analysis of secondary metabolites. However, these methods are labor and time intensive. In the breeding process, usually numerous single plants have to be analyzed and therefore, high throughput methods are required. In this article, some examples for alternative strategies are given. Besides spectroscopic methods like near infrared (NIR, also biosensoric approaches should be considered. For instance, several enzymes can oxidize or hydrolyze secondary metabolites in dependence of their functional groups. Polyphenols can be determined by laccases. Polyphenols like catechins and flavonoids contribute to the bioactivity of many medicinal plants. Also cysteine sulfoxides, which are typical for Allium species like garlic and onions, can be enzymatically determined with high specificity. Finally, toxic cyanogenic glycosides can be quantified by the enzyme cyanidase.

Nitrogen dioxide - current knowledge on the pollution situation and health effects; Stickstoffdioxid - Kenntnisstand zur Belastungssituation und zu gesundheitlichen Wirkungen

Energy Technology Data Exchange (ETDEWEB)

Muecke, H.G. [Umweltbundesamt, Berlin (Germany). Inst. fuer Wasser-, Boden- und Lufthygiene

1999-07-01

Feuerstellen (z.B. Gasherde, Gasheizautomaten und Heisswasserbereiter) und das Tabakrauchen sind die NO{sub 2}-Hauptquellen der Luftbelastung in Innenraeumen. NO{sub 2}-Messungen in deutschen Kuechen ergaben mittlere Konzentrationen von bis zu 50 {mu}g/m{sup 3} und Spitzenkonzentrationen von fast 200 {mu}G/m{sup 3}. Die NO{sub 2}-Konzentration in Innenraeumen ohne Stickstoffoxid-Quellen wird von den Aussenluftverhaeltnissen bestimmt und liegt im Durchschnitt zwischen 20 und 30 {mu}G/m{sup 3}. Die ueberarbeiteten NO{sub 2}-Richtwerte der WHO von 1998 sind: 40 {mu}g/m{sup 3} als Jahresmittel und 200 {mu}g/m{sup 3} als Einstundenmittel. Als oxidatives und gering wasserloesliches Reizgas entwickelt NO{sub 2} nach Inhalation seine Hauptwirkung in der Lungenperipherie. Veraenderungen von Lungenfunktionsparametern und Zunahme der bronchialen Reagibilitaet sind die wesentlichen gesundheitlichen Wirkungen. Expositionsstudien zur Belastungssituation zeigen, dass Innenraumquellen zusaetzlich im Mittel bis zu 5 {mu}g NO{sub 2}/m{sup 3} beitragen koennen und dass das Lueftungsverhalten als eine wesentliche Einflussgroesse mitangesehen werden kann. (orig.)

Use of low volatility mobile phases in electroosmotic thin-layer chromatography.

Science.gov (United States)

Berezkin, V G; Balushkin, A O; Tyaglov, B V; Litvin, E F

2005-08-19

A variant of electroosmotic thin-layer chromatography is suggested with the use of low volatility compounds as mobile phases aimed at drastically decreasing the evaporation of the mobile phase and improving the reproducibility of the method. The linear movement velocity of zones of separated compounds is experimentally shown to increase 2-12-fold in electroosmotic chromatography (compared to similar values in traditional TLC). The separation efficiency is also considerably increased.

Monodisperse microbeads of hypercrosslinked polystyrene for liquid and supercritical fluid chromatography

Science.gov (United States)

Tsyurupa, M. P.; Blinnikova, Z. K.; Il'in, M. M.; Davankov, V. A.; Parenago, O. O.; Pokrovskii, O. I.; Usovich, O. I.

2015-11-01

Monodisperse styrene-divinylbenzene (1 wt %) copolymer microbeads are obtained via the elaborate method of high-productivity precipitation polymerization. The crosslinking of this copolymer with chloromethyl methyl ether in the presence of Friedel-Crafts catalyst yields porous hypercrosslinked polymers with degrees of crosslinking that range from 200 to 500%. Microbead sorbents are shown to be suited for selective stationary phases for high-performance liquid chromatography and supercritical fluid chromatography.

Forensic applications of supercritical fluid chromatography - mass spectrometry.

Science.gov (United States)

Pauk, Volodymyr; Lemr, Karel

2018-06-01

Achievements of supercritical fluid chromatography with mass spectrometric detection made in the field of forensic science during the last decade are reviewed. The main topics include analysis of traditional drugs of abuse (e.g. cannabis, methamphetamine) as well as new psychoactive substances (synthetic cannabinoids, cathinones and phenethylamines), doping agents (anabolic steroids, stimulants, diuretics, analgesics etc.) and chemical warfare agents. Control of food authenticity, detection of adulteration and identification of toxic substances in food are also pointed out. Main aspects of an analytical workflow, such as sample preparation, separation and detection are discussed. A special attention is paid to the performance characteristics and validation parameters of supercritical fluid chromatography-mass spectrometric methods in comparison with other separation techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

Instrumentation for analytical scale supercritical fluid chromatography.

Science.gov (United States)

Berger, Terry A

2015-11-20

Analytical scale supercritical fluid chromatography (SFC) is largely a sub-discipline of high performance liquid chromatography (HPLC), in that most of the hardware and software can be used for either technique. The aspects that separate the 2 techniques stem from the use of carbon dioxide (CO2) as the main component of the mobile phase in SFC. The high compressibility and low viscosity of CO2 mean that pumps, and autosamplers designed for HPLC either need to be modified or an alternate means of dealing with compressibility needs to be found. The inclusion of a back pressure regulator and a high pressure flow cell for any UV-Vis detector are also necessary. Details of the various approaches, problems and solutions are described. Characteristics, such as adiabatic vs. isothermal compressibility, thermal gradients, and refractive index issues are dealt with in detail. Copyright © 2015 Elsevier B.V. All rights reserved.

From eco-efficiency in overall sustainable development in enterprises; Von Oekoeffizienz zu nachhaltiger Entwicklung in Unternehmen

Energy Technology Data Exchange (ETDEWEB)

Weizsaecker, E.U. von; Stigson, B; Seiler-Hausmann, J D [eds.

2001-07-01

Eco-efficiency is achieved when goods and services satisfy human needs, increase the quality of life, at prices which are competitive and when environmental impacts and resource intensity are decreased to a degree that they are in accordance with the expected capacities of the Earth. Eco-efficiency is a management approach that allows enterprises to carry out environmental protection measures from a market-oriented point of view. Eco-efficiency shows that ecology and economy do not contradict each other. On the contrary, in combination, they present a gain for enterprises. The motto is: To produce more with less. The WBCSD and its member enterprises have agreed to make economic growth and sustainable development the guideline for their economic entrepreneurial actions. The WBCSD supports the close co-operation of the economy, government and other organizations, as it is only together that we can help sustainable development to achieve a breakthrough. (orig.) [German] Oekoeffizienz ist dann erreicht, wenn Gueter und Dienstleistungen die menschlichen Beduerfnisse befriedigen, die Lebensqualitaet erhoehen und wettbewerbsfaehige Preise aufweisen, und die oekologischen Auswirkungen und die Ressourcenintensitaet waehrend des Lebenszyklus soweit verringert werden, dass eine Uebereinstimmung mit der voraussichtlichen Belastbarkeit der Erde besteht. Oekoeffizienz steht fuer einen Managementansatz, der Unternehmen erlaubt, Umweltschutzmassnahmen unter Marktgesichtspunkten durchzufuehren. Mit Oekoeffizienz wird zum Ausdruck gebracht, dass Oekonomie und Oekologie sich nicht ausschliessen, sondern in Kombination einen Gewinn fuer Unternehmen darstellen. Das Motto lautet: Mehr mit weniger produzieren. Der WBCSD und seine Mitgliedsunternehmen haben sich darauf verstaendigt, ihr Handeln von den Prinzipien des oekonomischen Wachstums und der nachhaltigen Entwicklung leiten zu lassen. Der WBCSD unterstuetzt die enge Zusammenarbeit von Wirtschaft, Staat und anderen Organisationen

Gas chromatography-mass spectrometry and high-performance liquid chromatography-diode array detection for dating of paper ink.

Science.gov (United States)

Díaz-Santana, Oscar; Vega-Moreno, Daura; Conde-Hardisson, Francisco

2017-09-15

An extraction and determination method is shown for the analysis of dyes and solvents present in two types of ballpoint pen inks that are deposited onto paper. Ink extracts are analysed using a combination of gas chromatography with mass spectrometry (GC-MS), and high-pressure liquid chromatography with photodiode array detection (HPLC-DAD), within a single sample extraction procedure. Seventeen solvents and thirteen dyes contained in two Montblanc ® inks (black and blue) were monitored for 45 months at monthly intervals, in order to determine variations in the concentrations of the compounds over time. We also studied the relative variations between different compounds and the generation of degradation products such as phenol. The concentration data obtained from these compounds during their exposure have been analysed and a multiple regression model is developed for each ink type that allows an estimate of the exposure time of the ink on paper with a maximum error of between 4 and 7 months. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous achiral-chiral analysis of pharmaceutical compounds using two-dimensional reversed phase liquid chromatography-supercritical fluid chromatography.

Science.gov (United States)

Venkatramani, C J; Al-Sayah, Mohammad; Li, Guannan; Goel, Meenakshi; Girotti, James; Zang, Lisa; Wigman, Larry; Yehl, Peter; Chetwyn, Nik

2016-02-01

A new interface was designed to enable the coupling of reversed phase liquid chromatography (RPLC) and supercritical fluid chromatography (SFC). This online two-dimensional chromatographic system utilizing RPLC in the first dimension and SFC in the second was developed to achieve simultaneous achiral and chiral analysis of pharmaceutical compounds. The interface consists of an eight-port, dual-position switching valve with small volume C-18 trapping columns. The peaks of interest eluting from the first RPLC dimension column were effectively focused as sharp concentration pulses on small volume C-18 trapping column/s and then injected onto the second dimension SFC column. The first dimension RPLC separation provides the achiral purity result, and the second dimension SFC separation provides the chiral purity result (enantiomeric excess). The results are quantitative enabling simultaneous achiral, chiral analysis of compounds. The interface design and proof of concept demonstration are presented. Additionally, comparative studies to conventional SFC and case studies of the applications of 2D LC-SFC in pharmaceutical analysis is presented. Copyright © 2015 Elsevier B.V. All rights reserved.

Investigating interactions between phospholipase B-Like 2 and antibodies during Protein A chromatography.

Science.gov (United States)

Tran, Benjamin; Grosskopf, Vanessa; Wang, Xiangdan; Yang, Jihong; Walker, Don; Yu, Christopher; McDonald, Paul

2016-03-18

Purification processes for therapeutic antibodies typically exploit multiple and orthogonal chromatography steps in order to remove impurities, such as host-cell proteins. While the majority of host-cell proteins are cleared through purification processes, individual host-cell proteins such as Phospholipase B-like 2 (PLBL2) are more challenging to remove and can persist into the final purification pool even after multiple chromatography steps. With packed-bed chromatography runs using host-cell protein ELISAs and mass spectrometry analysis, we demonstrated that different therapeutic antibodies interact to varying degrees with host-cell proteins in general, and PLBL2 specifically. We then used a high-throughput Protein A chromatography method to further examine the interaction between our antibodies and PLBL2. Our results showed that the co-elution of PLBL2 during Protein A chromatography is highly dependent on the individual antibody and PLBL2 concentration in the chromatographic load. Process parameters such as antibody resin load density and pre-elution wash conditions also influence the levels of PLBL2 in the Protein A eluate. Furthermore, using surface plasmon resonance, we demonstrated that there is a preference for PLBL2 to interact with IgG4 subclass antibodies compared to IgG1 antibodies. Copyright © 2016 Elsevier B.V. All rights reserved.

Use of laminar chromatographic methods for determination of separation conditions in column extraction chromatography

International Nuclear Information System (INIS)

Ghersini, G.; Cerrai, E.

1978-01-01

Possibilities of using laminar chromatographic methods (paper and thin-layer chromatography) to determine optimal separation conditions in column extraction chromatography are analysed. Most of the given laminar methods are presented as Rf-spectra, i.e. as dependences of Rf found experimentally on eluating solution component concentration. Interrelation between Rf and distribution coefficients of corresponding liquid extraction systems and retention volumes of chromatographic columns is considered. Literature data on extraction paper and thin-layer chromatography of elements with various immovable phases are presented

Isolation of oxidative degradation products of atorvastatin with supercritical fluid chromatography.

Science.gov (United States)

Klobčar, Slavko; Prosen, Helena

2015-12-01

The isolation of four oxidative degradation products of atorvastatin using preparative high-performance liquid chromatography applying at least two chromatographic steps is known from the literature. In this paper it is shown that the same four impurities could be isolated from similarly prepared mixtures in only one step using supercritical fluid chromatography. The methods for separation were developed and optimized. The preparation of the mixtures was altered in such a way as to enhance the concentration of desired impurities. Appropriate solvents were applied for collection of separated impurities in order to prevent degradation. The structures of the isolated impurities were confirmed and their purity determined. The preparative supercritical fluid chromatography has proven to be superior to preparative HPLC regarding achieved purity of standards applying fewer chromatographic as well as isolation steps. Copyright © 2015 John Wiley & Sons, Ltd.

Recent advances in liquid and gas chromatography methodology for extending coverage of the metabolome.

Science.gov (United States)

Haggarty, Jennifer; Burgess, Karl Ev

2017-02-01

The metabolome is the complete complement of metabolites (small organic biomolecules). In order to comprehensively understand the effect of stimuli on a biological system, it is important to detect as many of the metabolites within that system as possible. This review briefly describes some new advances in liquid and gas chromatography to improve coverage of the metabolome, including the serial combination of two columns in tandem, column switching and different variations of two-dimensional chromatography. Supercritical fluid chromatography could provide complimentary data to liquid and gas chromatography. Although there have been many recent advancements in the field of metabolomics, it is evident that a combination, rather than a single method, is required to approach full coverage of the metabolome. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Identification of chemical components in Baidianling Capsule based on gas chromatography-mass spectrometry and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry.

Science.gov (United States)

Wu, Wenying; Chen, Yu; Wang, Binjie; Sun, Xiaoyang; Guo, Ping; Chen, Xiaohui

2017-08-01

Baidianling Capsule, which is made from 16 Chinese herbs, has been widely used for treating vitiligo clinically. In this study, the sensitive and rapid method has been developed for the analysis of chemical components in Baidianling Capsule by gas chromatography-mass spectrometry in combination with retention indices and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Firstly, a total of 110 potential volatile compounds obtained from different extraction procedures including alkanes, alkenes, alkynes, ketones, ethers, aldehydes, alcohols, phenols, organic acids, esters, furans, pyrrole, acid amides, heterocycles, and oxides were detected from Baidianling Capsule by gas chromatography-mass spectrometry, of which 75 were identified by mass spectrometry in combination with the retention index. Then, a total of 124 components were tentatively identified by high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Fifteen constituents from Baidianling Capsule were accurately identified by comparing the retention times with those of reference compounds, others were identified by comparing the retention times and mass spectrometry data, as well as retrieving the reference literature. This study provides a practical strategy for rapidly screening and identifying the multiple constituents of a complex traditional Chinese medicine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theory of chromatography of partially cyclic polymers: Tadpole-type and manacle-type macromolecules.

Science.gov (United States)

Vakhrushev, Andrey V; Gorbunov, Alexei A

2016-02-12

A theory of chromatography is developed for partially cyclic polymers of tadpole- and manacle-shaped topological structures. We present exact equations for the distribution coefficient K at different adsorption interactions; simpler approximate formulae are also derived, relevant to the conditions of size-exclusion, adsorption, and critical chromatography. Theoretical chromatograms of heterogeneous partially cyclic polymers are simulated, and conditions for good separation by topology are predicted. According to the theory, an effective SEC-radius of tadpoles and manacles is mostly determined by the molar mass M, and by the linear-cyclic composition. In the interactive chromatography, the effect of molecular topology on the retention becomes significant. At the critical interaction point, partial dependences K(Mlin) and K(Mring) are qualitatively different: while being almost independent of Mlin, K increases with Mring. This behavior could be realized in critical chromatography-for separation of partially cyclic polymers by the number and molar mass of cyclic elements. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling of biopharmaceutical processes. Part 2: Process chromatography unit operation

DEFF Research Database (Denmark)

Kaltenbrunner, Oliver; McCue, Justin; Engel, Philip

2008-01-01

Process modeling can be a useful tool to aid in process development, process optimization, and process scale-up. When modeling a chromatography process, one must first select the appropriate models that describe the mass transfer and adsorption that occurs within the porous adsorbent. The theoret......Process modeling can be a useful tool to aid in process development, process optimization, and process scale-up. When modeling a chromatography process, one must first select the appropriate models that describe the mass transfer and adsorption that occurs within the porous adsorbent...

Fractionation of fecal neutral steroids by high performance liquid chromatography

International Nuclear Information System (INIS)

Jackson, E.M.; Kloss, C.A.; Weintraub, S.T.; Mott, G.E.

1985-01-01

Fecal neutral steroids were fractionated by high performance liquid chromatography (HPLC) into three major fractions: 5 beta-H, 3-keto steroids; 5 beta-H, 3 beta-hydroxy steroids; and 5 alpha-H and delta 5-3 beta-hydroxy steroids. This separation was achieved in about 10 minutes, with greater than 97% recovery of standards in each fraction. Gas-liquid chromatographic quantitation of fecal steroids fractionated by either HPLC or thin-layer chromatography gave nearly identical results. A method using both C18 reverse phase and silica HPLC to purify radiolabeled sterols is also described

Analytical method for high resolution liquid chromatography for quality control French Macaw

International Nuclear Information System (INIS)

Garcia Penna, Caridad M; Torres Amaro, Leonid; Menendez Castillo, Rosa; Sanchez, Esther; Martinez Espinosa, Vivian; Gonzalez, Maria Lidia; Rodriguez, Carlos

2007-01-01

Was developed and validated an analytical method for high resolution liquid chromatography applicable to quality control of drugs dry French Macaw (Senna alata L. Roxb.) With ultraviolet detection at 340 nm. The method for high resolution liquid chromatography used to quantify the sennosides A and B, main components, was validated and proved to be specific, linear, precise and accurate. (Author)

A Modern Apparatus for Performing Flash Chromatography: An Experiment for the Organic Laboratory

Science.gov (United States)

Naumiec, Gregory R.; Del Padre, Angela N.; Hooper, Matthew M.; Germaine, Alison St.; DeBoef, Brenton

2013-01-01

A modern apparatus for performing flash chromatography using commercially available, prepacked silica cartridges has been developed. The key advantage of this system, when compared to traditional flash chromatography, is its use of commercially available silica cartridges, which obviates the need for students to handle silica gel. The apparatus…

Dosage direct des alcools dans les carburols par chromatographie en phase gazeuse Direct Gas Chromatographie Determination of Alcohols in Gasolines Blended by Oxygenated Compounds

Directory of Open Access Journals (Sweden)

Petroff N.

2006-11-01

Full Text Available Dans cette étude, on décrit une méthode de chromatographie en phase gazeuse utilisant une colonne remplie ; elle permet de doser, sans préfractionnement, les alcools jusqu'aux butanols dans les carburols (carburants additionnés de composés oxygénés. La phase stationnaire sélectionnée est le glycérol. This report describes a gas chromatographie method using a packed column. It allows the direct determination of alcohols up to butanols in gasolines blended with oxygenated compounds without prefractionation. Glycerol has been selected as stationary phase.

Fractionation of lithium isotopes in cation-exchange chromatography

International Nuclear Information System (INIS)

Oi, Takao; Kawada, Kazuhiko; Kakihana, Hidetake; Hosoe, Morikazu

1991-01-01

Various methods for lithium isotope separation have been developed, and their applicability to large-scale enriched lithium isotope production has been assessed. Ion-exchange chromatography is one such method. Cation-exchange chromatography of lithium was carried out to investigate the lithium isotope effect in aqueous ion-exchange systems. The heavier isotope. 7 Li, was preferentially fractionated into the resin phase in every experiment conducted, and this result is consistent with the results of previous work. The value of the separation factor was 1.00089-1.00171 at 25C. A comparison of lithium isotope effect with those of potassium and rubidium indicated that the isotope effect originating from hydration is larger than the effect due to phase change for lithium, while the opposite is the case with potassium and rubidium

Ausrüstung von Starkstromanlagen mit elektronischen Betriebsmitteln / Achtung: Abschnitte 5.3.2.2.2 (einschließlich Kurve 2 in Bild 2) und 7.3.1.2 gelten erst ab Mai 1990. Bestehende Anlagen und Betriebsmittel einschließlich Ersatzlieferungen brauchen nicht den Anforderungen dieser neuen Norm angepaßt zu werden.

CERN Document Server

Deutsches Institut für Normung. Berlin

1988-01-01

Ausrüstung von Starkstromanlagen mit elektronischen Betriebsmitteln / Achtung: Abschnitte 5.3.2.2.2 (einschließlich Kurve 2 in Bild 2) und 7.3.1.2 gelten erst ab Mai 1990. Bestehende Anlagen und Betriebsmittel einschließlich Ersatzlieferungen brauchen nicht den Anforderungen dieser neuen Norm angepaßt zu werden.

Ultra Performance Liquid Chromatography Tandem Mass ...

African Journals Online (AJOL)

NICOLAAS

drugs alone.16. After a single oral dose of 120–800 mg of NTB in healthy sub- jects in a fasting state the peak plasma NTB concentration (tmax) was found to be 4–7 h, with a half-life of approximately 9–17 h.17 ... performance liquid chromatography mass spectrometry/mass .... to the likely biological plasma constituents.

Nano-liquid chromatography applied to enantiomers separation.

Science.gov (United States)

Fanali, Salvatore

2017-02-24

This paper presents the state of the art concerning the separation of chiral compounds by means of nano-liquid chromatography (nano-LC). The enantiomers' separation and determination are a subject of fundamental importance in various application fields such as pharmaceutical industry, biomedicine, food, agrochemical etc. Nano-LC is a miniaturized chromatographic technique offering some advantages over conventional ones such as low consumption of mobile phase, sample volume and amount of chiral stationary phase, reduced costs etc. This is reported in the first part of the paper illustrating the features of the nano-LC. In addition, chiral resolution methods are briefly illustrated. Some chiral selectors, used in high-performance liquid chromatography have also been applied in nano-LC including cyclodextrins, glycopeptide antibiotics, modified polysaccharides etc. This is discussed in the second part of the review. Finally some examples of the applications available in literature are reported. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiplex gas chromatography

Science.gov (United States)

Valentin, Jose R.

1990-01-01

The principles of the multiplex gas chromatography (GC) technique, which is a possible candidate for chemical analysis of planetary atmospheres, are discussed. Particular attention is given to the chemical modulators developed by present investigators for multiplex GC, namely, the thermal-desorption, thermal-decomposition, and catalytic modulators, as well as to mechanical modulators. The basic technique of multiplex GC using chemical modulators and a mechanical modulator is demonstrated. It is shown that, with the chemical modulators, only one gas stream consisting of the carrier in combination with the components is being analyzed, resulting in a simplified instrument that requires relatively few consumables. The mechanical modulator demonstrated a direct application of multiplex GC for the analysis of gases in atmosphere of Titan at very low pressures.

Frontal affinity chromatography: A unique research tool for biospecific interaction that promotes glycobiology

Science.gov (United States)

KASAI, Kenichi

2014-01-01

Combination of bioaffinity and chromatography gave birth to affinity chromatography. A further combination with frontal analysis resulted in creation of frontal affinity chromatography (FAC). This new versatile research tool enabled detailed analysis of weak interactions that play essential roles in living systems, especially those between complex saccharides and saccharide-binding proteins. FAC now becomes the best method for the investigation of saccharide-binding proteins (lectins) from viewpoints of sensitivity, accuracy, and efficiency, and is contributing greatly to the development of glycobiology. It opened a door leading to deeper understanding of the significance of saccharide recognition in life. The theory is also concisely described. PMID:25169774

Arsenic speciation by liquid chromatography coupled with ionspray tandem mass spectrometry

DEFF Research Database (Denmark)

Corr, J. J.; Larsen, Erik Huusfeldt

1996-01-01

Ionspray mass spectrometry, a well established organic analysis technique, has been coupled to high-performance liquid chromatography for speciation of organic arsenic compounds, The ionspray source and differentially pumped interface of the mass spectrometer were operated in dual modes...... fragmentation patterns showing molecular dissociation through an expected common product ion were obtained for the four arsenosugars, Molecular mode detection was utilized for qualitative verification of speciation analysis by high-performance liquid chromatography coupled to inductively coupled plasma mass...

Multi-column step-gradient chromatography system for automated ion exchange separations

International Nuclear Information System (INIS)

Rucker, T.L.

1985-01-01

A multi-column step-gradient chromatography system has been designed to perform automated sequential separations of radionuclides by ion exchange chromatography. The system consists of a digital programmer with automatic stream selection valve, two peristaltic pumps, ten columns, and a fraction collector. The automation allows complicated separations of radionuclides to be made with minimal analyst attention and allows for increased productivity and reduced cost of analyses. Results are reported for test separations on mixtures of radionuclides by the system

A retrospective data acquisition and evaluation on the characterization and prognosis for 776 patients with differentiated thyroid carcinomas in the Klinik und Poliklinik fuer Nuklearmedizin der Universitaet zu Koeln in the period from 1990 to 2005; Eine retrospektive Datenerhebung und Auswertung zur Charakterisierung und Prognose von 776 Patienten mit differenziertem Schilddruesenkarzinom der Klinik und Poliklinik fuer Nuklearmedizin der Universitaet zu Koeln im Zeitraum von 1990-2005

Energy Technology Data Exchange (ETDEWEB)

Meixner, Markus

2011-06-22

The author describes the retrospective data acquisition and evaluation on the characterization and prognosis for 776 patients (average age 40:1 years) with differentiated thyroid carcinomas in the Klinik und Poliklinik fuer Nuklearmedizin der Universitaet zu Koeln in the period from 1990 to 2005. The methodology includes patient-relevant data, examination data, imaging techniques and biochemical tests. Clinically important differences were found for papillary and follicular thyroid carcinoma. Further differences concern the localization of metastases. The author discusses the prognostic significance of the primary tumor radius in comparison with the so-called TNM classification for papillary and follicular thyroid carcinomas. It is concluded that the new version of the TNM classification offers only slight advantages with respect to the former version. It was also shown that the primary tumor size is adequate for prognostic estimations.

Separating esterase targets of organophosphorus compounds in the brain by preparative chromatography.

Science.gov (United States)

Mangas, I; Vilanova, E; Benabent, M; Estévez, J

2014-02-10

Low level exposure to organophosphorus esters (OPs) may cause long-term neurological effects and affect specific cognition domains in experimental animals and humans. Action on known targets cannot explain most of these effects by. Soluble carboxylesterases (EC 3.1.1.1) of chicken brain have been kinetically discriminated using paraoxon, mipafox and phenylmethyl sulfonylfluoride as inhibitors and phenyl valerate as a substrate. Three different enzymatic components were discriminated and called Eα, Eβ and Eγ. In this work, a fractionation procedure with various steps was developed using protein native separation methods by preparative HPLC. Gel permeation chromatography followed by ion exchange chromatography allowed enriched fractions with different kinetic behaviors. The soluble chicken brain fraction was fractionated, while total esterase activity, proteins and enzymatic components Eα, Eβ and Eγ were monitored in each subfraction. After the analysis, 13 fractions were pooled and conserved. Preincubation of the soluble chicken brain fraction of with the organophosphorus mipafox gave rise to a major change in the ion exchange chromatography profile, but not in the molecular exchanged chromatography profile, which suggest that mipafox permanently modifies the ionic properties of numerous proteins. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Polymer Analysis by Liquid Chromatography/Electrospray Ionization Time-of-Flight Mass Spectrometry.

Science.gov (United States)

Nielen, M W; Buijtenhuijs, F A

1999-05-01

Hyphenation of liquid chromatography (LC) techniques with electrospray ionization (ESI) orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry (MS) provides both MS-based structural information and LC-based quantitative data in polymer analysis. In one experimental setup, three different LC modes are interfaced with MS:  size-exclusion chromatography (SEC/MS), gradient polymer elution chromatography (GPEC/MS), and liquid chromatography at the critical point of adsorption (LCCC/MS). In SEC/MS, both absolute mass calibration of the SEC column based on the polymer itself and determination of monomers and end groups from the mass spectra are achieved. GPEC/MS shows detailed chemical heterogeneity of the polymer and the chemical composition distribution within oligomer groups. In LCCC/MS, the retention behavior is primarily governed by chemical heterogeneities, such as different end group functionalities, and quantitative end group calculations can be easily made. The potential of these methods and the benefit of time-of-flight analyzers in polymer analysis are discussed using SEC/MS of a polydisperse poly(methyl methacrylate) sample, GPEC/MS of dipropoxylated bisphenol A/adipic acid polyester resin, LCCC/MS of alkylated poly(ethylene glycol), and LCCC/MS of terephthalic acid/neopentyl glycol polyester resin.

Application of coupled affinity-sizing chromatography for the detection of proteolyzed HSA-tagged proteins.

Science.gov (United States)

London, Anne Serdakowski; Patel, Kunal; Quinn, Lisa; Lemmerer, Martin

2015-04-01

Coupled affinity liquid chromatography and size exclusion chromatography (ALC-SEC) is a technique that has been shown to successfully report product quality of proteins during cell expression and prior to the commencement of downstream processing chromatography steps. This method was applied to monitoring the degradation and subsequent partial remediation of a HSA-tagged protein which showed proteolysis, allowing for rapid cell line development to address this product quality dilemma. This paper outlines the novel application of this method for measuring and addressing protease-induced proteolysis. Copyright © 2014 Elsevier Inc. All rights reserved.

Analytical FcRn affinity chromatography for functional characterization of monoclonal antibodies

Science.gov (United States)

Schlothauer, Tilman; Rueger, Petra; Stracke, Jan Olaf; Hertenberger, Hubert; Fingas, Felix; Kling, Lothar; Emrich, Thomas; Drabner, Georg; Seeber, Stefan; Auer, Johannes; Koch, Stefan; Papadimitriou, Apollon

2013-01-01

The neonatal Fc receptor (FcRn) is important for the metabolic fate of IgG antibodies in vivo. Analysis of the interaction between FcRn and IgG in vitro might provide insight into the structural and functional integrity of therapeutic IgG that may affect pharmacokinetics (PK) in vivo. We developed a standardized pH gradient FcRn affinity liquid chromatography method with conditions closely resembling the physiological mechanism of interaction between IgG and FcRn. This method allows the separation of molecular IgG isoforms, degradation products and engineered molecules based on their affinity to FcRn. Human FcRn was immobilized on the column and a linear pH gradient from pH 5.5 to 8.8 was applied. FcRn chromatography was used in comparison to surface plasmon resonance to characterize different monoclonal IgG preparations, e.g., oxidized or aggregated species. Wild-type and engineered IgGs were compared in vitro by FcRn chromatography and in vivo by PK studies in huFcRn transgenic mice. Analytical FcRn chromatography allows differentiation of IgG samples and variants by peak pattern and retention time profile. The method can distinguish: 1) IgGs with different Fabs, 2) oxidized from native IgG, 3) aggregates from monomer and 4) antibodies with mutations in the Fc part from wild-type IgGs. Changes in the FcRn chromatographic behavior of mutant IgGs relative to the wild-type IgG correlate to changes in the PK profile in the FcRn transgenic mice. These results demonstrate that FcRn affinity chromatography is a useful new method for the assessment of IgG integrity. PMID:23765230

Deformation and degradation of polymers in ultra-high-pressure liquid chromatography.

Science.gov (United States)

Uliyanchenko, Elena; van der Wal, Sjoerd; Schoenmakers, Peter J

2011-09-28

Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles and narrow bore tubing in combination with high pressures generate significant shear and extensional forces in UHPLC systems, which may affect polymer chains. At high stress conditions flexible macromolecules may become extended and eventually the chemical bonds in the molecules can break. Deformation and degradation of macromolecules will affect the peak retention and the peak shape in the chromatogram, which may cause errors in the obtained results (e.g. the calculated molecular-weight distributions). In the present work we explored the limitations of UHPLC for the analysis of polymers. Degradation and deformation of macromolecules were studied by collecting and re-injecting polymer peaks and by off-line two-dimensional liquid chromatography. Polystyrene standards with molecular weight of 4 MDa and larger were found to degrade at UHPLC conditions. However, for most polymers degradation could be avoided by using low linear velocities. No degradation of 3-MDa PS (and smaller) was observed at linear velocities up to 7 mm/s. The column frits were implicated as the main sources of polymer degradation. The extent of degradation was found to depend on the type of the column and on the column history. At high flow rates degradation was observed without a column being installed. We demonstrated that polymer deformation preceded degradation. Stretched polymers eluted from the column in slalom chromatography mode (elution order opposite to that in SEC or HDC). Under certain conditions we observed co-elution of large and small PS molecules though a convolution of slalom chromatography and hydrodynamic chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

Mathematical analysis of frontal affinity chromatography in particle and membrane configurations.

Science.gov (United States)

Tejeda-Mansir, A; Montesinos, R M; Guzmán, R

2001-10-30

The scaleup and optimization of large-scale affinity-chromatographic operations in the recovery, separation and purification of biochemical components is of major industrial importance. The development of mathematical models to describe affinity-chromatographic processes, and the use of these models in computer programs to predict column performance is an engineering approach that can help to attain these bioprocess engineering tasks successfully. Most affinity-chromatographic separations are operated in the frontal mode, using fixed-bed columns. Purely diffusive and perfusion particles and membrane-based affinity chromatography are among the main commercially available technologies for these separations. For a particular application, a basic understanding of the main similarities and differences between particle and membrane frontal affinity chromatography and how these characteristics are reflected in the transport models is of fundamental relevance. This review presents the basic theoretical considerations used in the development of particle and membrane affinity chromatography models that can be applied in the design and operation of large-scale affinity separations in fixed-bed columns. A transport model for column affinity chromatography that considers column dispersion, particle internal convection, external film resistance, finite kinetic rate, plus macropore and micropore resistances is analyzed as a framework for exploring further the mathematical analysis. Such models provide a general realistic description of almost all practical systems. Specific mathematical models that take into account geometric considerations and transport effects have been developed for both particle and membrane affinity chromatography systems. Some of the most common simplified models, based on linear driving-force (LDF) and equilibrium assumptions, are emphasized. Analytical solutions of the corresponding simplified dimensionless affinity models are presented. Particular

Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

Directory of Open Access Journals (Sweden)

Árpád Gyéresi

2013-02-01

Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

Supercritical Fluid Chromatography--Theoretical Background and Applications on Natural Products.

Science.gov (United States)

Hartmann, Anja; Ganzera, Markus

2015-11-01

The use of supercritical fluid chromatography for natural product analysis as well as underlying theoretical mechanisms and instrumental requirements are summarized in this review. A short introduction focusing on the historical development of this interesting separation technique is followed by remarks on the current instrumental design, also describing possible detection modes and useable stationary phases. The overview on relevant applications is grouped based on their basic intention, may it be (semi)preparative or purely analytical. They indicate that supercritical fluid chromatography is still primarily considered for the analysis of nonpolar analytes like carotenoids, fatty acids, or terpenes. The low polarity of supercritical carbon dioxide, which is used with modifiers almost exclusively as a mobile phase today, combined with high efficiency and fast separations might explain the popularity of supercritical fluid chromatography for the analysis of these compounds. Yet, it has been shown that more polar natural products (e.g., xanthones, flavonoids, alkaloids) are separable too, with the same (if not superior) selectivity and reproducibility than established approaches like HPLC or GC. Georg Thieme Verlag KG Stuttgart · New York.

Gas Chromatography Mass Spectrometry of Quassia undulata Seed ...

African Journals Online (AJOL)

Prof. Ogunji

The use of gas chromatography mass spectrometry (GC MS) as a sensitive and specific technique ... cold flow properties and stability of the fuel to oxidation, peroxidation and polymerization .... determinants of both the physical and chemical ...

Gas Chromatography-Mass Spectrometric Analysis of Nematicidal ...

African Journals Online (AJOL)

Purpose: To investigate the chemical composition and nematicidal activity of the essential oil of. Valeriana amurensis ... Methods: The essential oil of V. amurensis roots was obtained by hydrodistillation and analyzed by gas chromatography (GC) ..... Aβ1-40 and Caspase-3 in Alzheimer's disease model rat's brain. J Chin ...

Improved purification of immunoglobulin G from plasma by mixed-mode chromatography.

Science.gov (United States)

Chai, Dong-Sheng; Sun, Yan; Wang, Xiao-Ning; Shi, Qing-Hong

2014-12-01

Efficient loading of immunoglobulin G in mixed-mode chromatography is often a serious bottleneck in the chromatographic purification of immunoglobulin G. In this work, a mixed-mode ligand, 4-(1H-imidazol-1-yl) aniline, was coupled to Sepharose Fast Flow to fabricate AN SepFF adsorbents with ligand densities of 15-64 mmol/L, and the chromatographic performances of these adsorbents were thoroughly investigated to identify a feasible approach to improve immunoglobulin G purification. The results indicate that a critical ligand density exists for immunoglobulin G on the AN SepFF adsorbents. Above the critical ligand density, the adsorbents showed superior selectivity to immunoglobulin G at high salt concentrations, and also exhibited much higher dynamic binding capacities. For immunoglobulin G purification, both the yield and binding capacity increased with adsorbent ligand density along with a decrease in purity. It is difficult to improve the binding capacity, purity, and yield of immunoglobulin G simultaneously in AN SepFF chromatography. By using tandem AN SepFF chromatography, a threefold increase in binding capacity as well as high purity and yield of immunoglobulin G were achieved. Therefore, the tandem chromatography demonstrates that AN SepFF adsorbent is a practical and feasible alternative to MEP HyperCel adsorbents for immunoglobulin G purification. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Isolation of Methoxyfuranocoumarins From Ammi majus by Centrifugal Partition Chromatography.

Science.gov (United States)

Bartnik, Magdalena; Mazurek, Anna Katarzyna

2016-01-01

Pure methoxyfuranocoumarins were isolated from Ammi majus L. by use of low-pressure column chromatography (LPCC) followed by centrifugal partition chromatography (CPC). The concentrated petroleum ether extract from fruits of A. majus was fractionated on a silica gel column using a gradient of ethyl acetate in dichloromethane (0-80%, v/v). Coumarin-rich fractions were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography with diode array detection (HPLC/DAD). Xanthotoxin (8-MOP) and isopimpinellin (isoP), structurally similar compounds, were isolated in one fraction (FR6). To avoid multistep and long-lasting TLC preparation, optimization of CPC conditions has been performed. In one run, an effective separation of 8-MOP and isoP was achieved. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (10 : 8 : 10 : 9; v/v) in an ascending mode (the aqueous phase was a stationary phase, and the organic phase was a mobile phase), with flow rate 3 mL/min and rotation speed 1,600 r.p.m., was used. The identification and high purities of isolated 8-MOP (98.7%) and isoP (100%) were confirmed by HPLC/DAD assay, when compared with standards. The developed CPC method could be applied to the effective isolation of 8-MOP and isoP from plant extracts. The high purity of obtained compounds makes possible further exploitation of these components in biological studies. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Validation of a confirmatory method for the determination of melamine in egg by gas chromatography-mass spectrometry and ultra-performance liquid chromatography-tandem mass spectrometry

International Nuclear Information System (INIS)

Xia Xi; Ding Shuangyang; Li Xiaowei; Gong Xiao; Zhang Suxia; Jiang Haiyang; Li Jiancheng; Shen Jianzhong

2009-01-01

A sensitive and reliable method was developed and validated for detection and confirmation of melamine in egg based on gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Trichloroacetic acid solution was used for sample extraction and precipitation of proteins. The aqueous extracts were subjected to solid-phase extraction by mixed-mode reversed-phase/strong cation-exchange cartridges. Using ultra-performance liquid chromatography and electrospray ionization in the positive ion mode, melamine was determined by LC-MS/MS, which was completed in 5 min for each injection. For the GC-MS analysis, extracted melamine was derivatized with N,O-bis(trimethylsilyl)trifluoracetamide prior to selected ion monitoring detection in electron impact mode. The average recovery of melamine from fortified samples ranged from 85.2% to 103.2%, with coefficients of variation lower than 12%. The limit of detection obtained by GC-MS and UPLC-MS/MS was 10 and 5 μg kg -1 , respectively. This validated method was successfully applied to the determination of melamine in real samples from market.

Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

Science.gov (United States)

Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

2015-07-03

The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of genetic algorithms for parameter estimation in liquid chromatography

International Nuclear Information System (INIS)

Hernandez Torres, Reynier; Irizar Mesa, Mirtha; Tavares Camara, Leoncio Diogenes

2012-01-01

In chromatography, complex inverse problems related to the parameters estimation and process optimization are presented. Metaheuristics methods are known as general purpose approximated algorithms which seek and hopefully find good solutions at a reasonable computational cost. These methods are iterative process to perform a robust search of a solution space. Genetic algorithms are optimization techniques based on the principles of genetics and natural selection. They have demonstrated very good performance as global optimizers in many types of applications, including inverse problems. In this work, the effectiveness of genetic algorithms is investigated to estimate parameters in liquid chromatography

Rapid and Convenient Separation of Chitooligosaccharides by Ion-Exchange Chromatography

Science.gov (United States)

Wu, Yuxiao; Lu, Wei-Peng; Wang, Jianing; Gao, Yunhua; Guo, Yanchuan

2017-12-01

Pervious methods for separation of highly purified chitooligosaccharides was time-consuming and labor-intensive, which limited the large-scale production. This study developed a convenient ion-exchange chromatography using the ÄKTA™ avant 150 chromatographic system. Five fractions were automatically collected under detecting the absorption at 210 nm. The fractions were analyzed by high-performance liquid chromatography. It proved that they primarily comprised chitobiose, chitotriose, chitotetraose, chitopentaose, and chitohexaose, respectively, with chromatographic purities over 90%. The separation process was rapid, convenient and could be monitored on-line, which would be benefit for the mass production of chitooligosaccharides.

Comprehensive lipidomic analysis of human plasma using multidimensional liquid- and gas-phase separations: Two-dimensional liquid chromatography-mass spectrometry vs. liquid chromatography-trapped-ion-mobility-mass spectrometry.

Science.gov (United States)

Baglai, Anna; Gargano, Andrea F G; Jordens, Jan; Mengerink, Ynze; Honing, Maarten; van der Wal, Sjoerd; Schoenmakers, Peter J

2017-12-29

Recent advancements in separation science have resulted in the commercialization of multidimensional separation systems that provide higher peak capacities and, hence, enable a more-detailed characterization of complex mixtures. In particular, two powerful analytical tools are increasingly used by analytical scientists, namely online comprehensive two-dimensional liquid chromatography (LC×LC, having a second-dimension separation in the liquid phase) and liquid chromatography-ion mobility-spectrometry (LC-IMS, second dimension separation in the gas phase). The goal of the current study was a general assessment of the liquid-chromatography-trapped-ion-mobility-mass spectrometry (LC-TIMS-MS) and comprehensive two-dimensional liquid chromatography-mass spectrometry (LC×LC-MS) platforms for untargeted lipid mapping in human plasma. For the first time trapped-ion-mobility spectrometry (TIMS) was employed for the separation of the major lipid classes and ion-mobility-derived collision-cross-section values were determined for a number of lipid standards. The general effects of a number of influencing parameters have been inspected and possible directions for improvements are discussed. We aimed to provide a general indication and practical guidelines for the analyst to choose an efficient multidimensional separation platform according to the particular requirements of the application. Analysis time, orthogonality, peak capacity, and an indicative measure for the resolving power are discussed as main characteristics for multidimensional separation systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

International Nuclear Information System (INIS)

Dodi, Alain; Bouscarel, Maelle

2008-01-01

This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

Energy Technology Data Exchange (ETDEWEB)

Dodi, Alain; Bouscarel, Maelle [Commissariat a l' energie atomique - C.E.A, Centre d' Etude de Cadarache, Laboratoire d' Analyses Radiochimiques et Chimiques, St Paul lez Durance (France)

2008-07-01

This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

Validated High Performance Liquid Chromatography Method for ...

African Journals Online (AJOL)

Purpose: To develop a simple, rapid and sensitive high performance liquid chromatography (HPLC) method for the determination of cefadroxil monohydrate in human plasma. Methods: Schimadzu HPLC with LC solution software was used with Waters Spherisorb, C18 (5 μm, 150mm × 4.5mm) column. The mobile phase ...

Ion exchange and liquid column chromatography

International Nuclear Information System (INIS)

Walton, H.F.

1980-01-01

Major accomplishments in liquid chromatography for the past two years and reported in journals available to December 31, 1979 are reviewed. Emphasis has been placed on principles and methodology with some representative examples of application included. Applications are illustrated in two rather lenghtly tables, one covering inorganic ions and the other covering organic compounds. 544 references, 8 books, and 15 reviews are listed in the bibliography

Clinical applications of fast liquid chromatography: a review on the analysis of cardiovascular drugs and their metabolites.

Science.gov (United States)

Baranowska, Irena; Magiera, Sylwia; Baranowski, Jacek

2013-05-15

One of the major challenges facing the medicine today is developing new therapies that enhance human health. To help address these challenges the utilization of analytical technologies and high-throughput automated platforms has been employed; in order to perform more experiments in a shorter time frame with increased data quality. In the last decade various analytical strategies have been established to enhance separation speed and efficiency in liquid chromatography applications. Liquid chromatography is an increasingly important tool for monitoring drugs and their metabolites. Furthermore, liquid chromatography has played an important role in pharmacokinetics and metabolism studies at these drug development stages since its introduction. This paper provides an overview of current trends in fast chromatography for the analysis of cardiovascular drugs and their metabolites in clinical applications. Current trends in fast liquid chromatographic separations involve monolith technologies, fused-core columns, high-temperature liquid chromatography (HTLC) and ultra-high performance liquid chromatography (UHPLC). The high specificity in combination with high sensitivity makes it an attractive complementary method to traditional methodology used for routine applications. The practical aspects of, recent developments in and the present status of fast chromatography for the analysis of biological fluids for therapeutic drug and metabolite monitoring, pharmacokinetic studies and bioequivalence studies are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

Combined high-performance liquid chromatography/32P-postlabeling assay of N7-methyldeoxyguanosine

International Nuclear Information System (INIS)

Shields, P.G.; Povey, A.C.; Wilson, V.L.; Weston, A.; Harris, C.C.

1990-01-01

A highly sensitive and specific assay for the detection of N7-methyl-2'-deoxyguanosine (N7methyldG) has been developed by combining high-performance liquid chromatography, 32 P-postlabeling, and nucleotide chromatography. Separation of normal nucleotides and adducts by high-performance liquid chromatography and then combining a portion of 2'-deoxyguanosine to the N7methyldG allows for quantitation using an internal standard. The directly determined molar ratio is not subject to errors in digestion, variable ATP-specific activity, or assumptions in relative adduct-labeling efficiency. The detection limit was one N7methyldG adduct in 10(7) unmodified 2'-deoxyguanosine bases. N7methyldG adducts have been detected in 5 human lung samples in which O6-methyl-2'-deoxyguanosine adducts had been previously determined. The mean ratio of N7methyldG to O6-methyl-2'-deoxyguanosine was determined to be approximately 10. The current assay complements the high-performance liquid chromatography/ 32 P-postlabeling assay for O6-methyl-2'-deoxyguanosine and increases the detection sensitivity of DNA methylated by exogenous alkylating agents

Characterization of the fermentation process by gas chromatography Lasiodiplodia theobromae and gas chromatography coupled with mass spectrometry

International Nuclear Information System (INIS)

Castillo Portela, Grolamys; Eng Sanchez, Felipe; Nogueiras Lima, Clara

2014-01-01

Lasiodiplodia theobromae is a fungus, which has been reported by some authors as a high yield producer of the phytohormone jasmonic acid (JA). An indigenous strain of this fungus has been used for producing a fermentation broth with a high JA concentration by the Cuban Research Institute for Sugar Cane Derivatives (ICIDCA), registered as BIOJAS. The broth has been applied to some agricultural crops and demonstrated its economic feasibility as plant growth regulator and biological control of various phytopathogenic microorganisms and pests. Both fermentation broth and biomass from this fungus contain some other metabolites having bioactive properties, for instance, fatty acids. This paper shows the composition and quantification of fatty acids in the biomass using Gas Chromatography (GC) and the identification of substances profile in fermentation broth by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The most fatty acids in the biomass are palmitic, stearic, oleic, linoleic and linolenic acids, being oleic acid the major component. On the other hand, 2,32 % of fatty acid esters; 2,47 % of alkenes; 14,40 % of alcohols; 30,15 % of aldehydes and 21,73 % of paraffins were detected in the composition of fermentation broth

pH-zone-refining elution-extrusion countercurrent chromatography: Separation of hydroxyanthraquinones from Cassiae semen.

Science.gov (United States)

Bu, Zhisi; Lv, Liqiong; Li, Xingnuo; Chu, Chu; Tong, Shengqiang

2017-11-01

Seven hydroxyanthraquinones were successfully separated from the traditional Chinese medicinal herb Cassiae semen by conventional and pH-zone-refining countercurrent chromatography with an environmentally friendly biphasic solvent system, in which elution-extrusion mode was investigated for pH-zone-refining countercurrent chromatography for the first time. A two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/water (5:3:4:4, v/v/v/v) was used for the conventional countercurrent chromatography while the same system with a different volume ratio n-hexane/ethyl acetate/ethanol/water (3:5:2:6, v/v/v/v) was used for pH-zone-refining countercurrent chromatography, in which 20 mmol/L of trifluoroacetic acid was added in the organic phase as a retainer and 15 mmol/L of ammonia was added to the aqueous phase as an eluter. A 400 mg crude sample could be well separated by pH-zone-refining countercurrent chromatography, yielding 53 mg of aurantio-obtusin, 40 mg of chryso-obtusin, 18 mg of obtusin, 24 mg of obtusifolin, 10 mg of emodin, and 105 mg of the mixture of chrysophanol and physcion with a purity of over 95.8, 95.7, 96.9, 93.5, 97.4, 77.1, and 19.8%, as determined by high-performance liquid chromatography. Furthermore, the difference in elution sequence between conventional and pH-zone-refining mode was observed and discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Purification of tracer for somatomedin C radioimmunoassay by hydrophobic interaction chromatography

Energy Technology Data Exchange (ETDEWEB)

Baxter, R.C.; Brown, A.S.

1982-03-01

A tracer for use in the somatomedin C radiommunoassay by hydrophobic interaction chromatography was purified. Material showing greatest immunoreactivity binds to Octyl Sepharose CL-4B (Pharmacia) in a buffer mixture consisting of 130 mL of acetonitrile and 870 mL of 0.1 mol/L NH/sub 4/HCO/sub 3/, pH 7.8, but is eluted by increasing the acetonitrile content to 180 mL/L. As compared with tracer purified by binding to specific antiserum in liquid phase, precipitating the complex with second antibody, and then dissociating by gel chromatography at acid pH, this tracer shows equal immunoreactivity against specific somatomedin C antiserum. Either preparation allows excellent discrimination between extracts of normal, acromegalic, and hypopituitary plasma samples; thus either is suitable for use in the somatomedin C radioimmunoassay. Tracer purification by hydrophobic interaction chromatography is rapid and inexpensive. It may be useful in preparing highly immunoreactive tracers for other peptide radioimmunoassays.

Immunoaffinity chromatography of abscisic acid combined with electrospray liquid chromatography–mass spectrometry

Czech Academy of Sciences Publication Activity Database

Hradecká, Veronika; Novák, Ondřej; Havlíček, Libor; Strnad, Miroslav

2007-01-01

Roč. 847, č. 2 (2007), s. 162-173 ISSN 1570-0232 R&D Projects: GA MŠk(CZ) LC06034; GA AV ČR IBS5038351 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * immunoaffinity chromatography * liquid chromatography-mass spectrometry Subject RIV: ED - Physiology Impact factor: 2.935, year: 2007

Wie wichtig ist der Unterricht in Medizinethik und Medizingeschichte im Medizinstudium? Eine empirische Studie zu den Einschätzungen Studierender [How Important is Medical Ethics and History of Medicine Teaching in the Medical Curriculum? An Empirical Approach towards Students' Views

Directory of Open Access Journals (Sweden)

Schulz, Stefan

2012-02-01

negative impact. Therefore the teaching of GTE should already begin in the 1 semester. The teaching of GTE must take into account that even right at the start of their studies, students judge medical ethics and the history of medicine differently.[german] Zielsetzung: Es wurde untersucht, wie Studierende zu Beginn und im Verlauf ihres Studiums den Unterricht in Medizinethik und Medizingeschichte einschätzen und welchen Einfluss der durchgeführte bzw. fehlende fachspezifische Unterricht in Geschichte, Theorie und Ethik der Medizin (GTE auf die Wertschätzung der Fächer hat.Methodik: Befragt wurden im WS 2005/6 insgesamt 533 Studierende des 1. und 5. Fachsemesters aus dem Bochumer Modell- (GTE-Unterricht ab dem 1. Fachsemester und Regelstudiengang (GTE-Unterricht im 5./6. Fachsemester. Befragt wurde jeweils vor und nach dem 1. bzw. 5. oder 6. Semester. Wir fragten nach der Einschätzung der Bedeutung der Lehre in Medizinethik und Medizingeschichte für die Studierenden, nach der Bedeutung der Fächer für den Arzt sowie nach ihrer Lehr- und Prüfbarkeit (Likert Skala von -2 (stimme überhaupt nicht zu bis +2 (stimme völlig zu.Ergebnisse: 331 Fragebogenpaare wurden in die Studie einbezogen. Zwischen den Studierenden der beiden Studiengänge fanden sich zu Beginn des 1. Semesters keine signifikanten Unterschiede. Die Einschätzungen der Medizinethik und der Medizingeschichte unterschieden sich zu Beginn des Studiums jedoch signifikant: Die Bedeutung der Medizinethik für die eigene Person und für den Arzt wurde als sehr hoch eingeschätzt, deutlich schlechter ihre Lehr- und Prüfbarkeit. Für die Medizingeschichte waren die Ergebnisse genau entgegengesetzt.Durch den GTE-Unterricht verbesserten sich dann in beiden Studiengängen die Einschätzungen in den vorher weniger gut bewerteten Items. Fehlender Unterricht führte zur Verschlechterung der Einschätzung beider Fächer in den vorher gut bewerteten Items.Schlussfolgerung: Im Einklang mit der Literatur unterst

Qualitative and Quantitative Analysis of Volatile Components of Zhengtian Pills Using Gas Chromatography Mass Spectrometry and Ultra-High Performance Liquid Chromatography.

Science.gov (United States)

Liu, Cui-Ting; Zhang, Min; Yan, Ping; Liu, Hai-Chan; Liu, Xing-Yun; Zhan, Ruo-Ting

2016-01-01

Zhengtian pills (ZTPs) are traditional Chinese medicine (TCM) which have been commonly used to treat headaches. Volatile components of ZTPs extracted by ethyl acetate with an ultrasonic method were analyzed by gas chromatography mass spectrometry (GC-MS). Twenty-two components were identified, accounting for 78.884% of the total components of volatile oil. The three main volatile components including protocatechuic acid, ferulic acid, and ligustilide were simultaneously determined using ultra-high performance liquid chromatography coupled with diode array detection (UHPLC-DAD). Baseline separation was achieved on an XB-C18 column with linear gradient elution of methanol-0.2% acetic acid aqueous solution. The UHPLC-DAD method provided good linearity (R (2) ≥ 0.9992), precision (RSD components, protocatechuic acid, ferulic acid, and ligustilide, in 13 batches of ZTPs, which is suitable for discrimination and quality assessment of ZTPs.

Beta-induced fluorescence detection in liquid chromatography

International Nuclear Information System (INIS)

Malcolme-Lawes, D.J.; Massey, S.; Warwick, P.

1981-01-01

A theoretical analysis of beta-induced fluorescence is used to determine the factors which influence the sensitivity of the technique as applied to liquid chromatography. Equations are presented for detector response and for signal-to-noise ratios and the theoretical response for a typical detector is compared with experimentally determined values. (author)

Determination of trimethyllead reference material using high performance liquid chromatography-inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Lu Hai; Wei Chao; Wang Jun; Chao Jingbo; Zhou Tao; Chen Dazhou

2005-01-01

A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) was combined, and the chromatography conditions were optimized. The stability and homogeneity of a trimethyllead reference material were determined using this method. (authors)

Determination of Four Major Saponins in Skin and Endosperm of Seeds of Horse Chestnut (Aesculus Hippocastanum L.) Using High Performance Liquid Chromatography with Positive Confirmation by Thin Layer Chromatography

OpenAIRE

Abudayeh, Zead Helmi Mahmoud; Al Azzam, Khaldun Mohammad; Naddaf, Ahmad; Karpiuk, Uliana Vladimirovna; Kislichenko, Viktoria Sergeevna

2015-01-01

urpose: To separate and quantify four major saponins in the extracts of the skin and the endosperm of seeds of horse chestnut (Aesculus hippocastanum L.) using ultrasonic solvent extraction followed by a high performance liquid chromatography-diode array detector (HPLC-DAD) with positive confirmation by thin layer chromatography (TLC). Methods: The saponins: escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted using ultrasonic extraction method. The optimized ex...

Microchip-based monolithic column for high performance liquid chromatography

Data.gov (United States)

National Aeronautics and Space Administration — We have developed microchip based monolithic columns that can be used for liquid chromatography of small organic molecules, as well as, macromolecules such as...

Approaches for on-line coupling of extraction and chromatography

Energy Technology Data Exchange (ETDEWEB)

Hyoetylaeinen, Tuulia; Riekkola, Marja-Liisa [Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki (Finland)

2004-04-01

This review provides an overview of the approaches available in order to perform on-line coupling of various extraction techniques with liquid and gas chromatography, for the analysis of semivolatile and nonvolatile analytes in liquid and solid samples. The main focus is on the instrumental set-up of these techniques. Selected real applications are described by way of illustration. The extraction methods suitable for on-line coupling covered in this review are: liquid-liquid extraction, solid-phase extraction, membrane-based techniques, pressurised liquid extraction, supercritical fluid extraction, and microwave- and sonication-assisted extractions. The following systems are not covered in this review: on-line coupled solid-phase extraction-liquid chromatography, purge-and-trap-GC, and membrane extraction with a sorbent interface-GC. (orig.)

Protein A chromatography increases monoclonal antibody aggregation rate during subsequent low pH virus inactivation hold

Science.gov (United States)

Mazzer, Alice R.; Perraud, Xavier; Halley, Jennifer; O’Hara, John; Bracewell, Daniel G.

2015-01-01

Protein A chromatography is a near-ubiquitous method of mAb capture in bioprocesses. The use of low pH buffer for elution from protein A is known to contribute to product aggregation. Yet, a more limited set of evidence suggests that low pH may not be the sole cause of aggregation in protein A chromatography, rather, other facets of the process may contribute significantly. This paper presents a well-defined method for investigating this problem. An IgG4 was incubated in elution buffer after protein A chromatography (typical of the viral inactivation hold) and the quantity of monomer in neutralised samples was determined by size exclusion chromatography; elution buffers of different pH values predetermined to induce aggregation of the IgG4 were used. Rate constants for monomer decay over time were determined by fitting exponential decay functions to the data. Similar experiments were implemented in the absence of a chromatography step, i.e. IgG4 aggregation at low pH. Rate constants for aggregation after protein A chromatography were considerably higher than those from low pH exposure alone; a distinct shift in aggregation rates was apparent across the pH range tested. PMID:26346187

Comprehensive two-dimensional liquid chromatography with on-line Fourier-transform-infrared-spectroscopy detection for the characterization of copolymers

NARCIS (Netherlands)

Kok, S.J.; Hankemeier, T.; Schoenmakers, P.J.

2005-01-01

The on-line coupling of comprehensive two-dimensional liquid chromatography (liquid chromatography × size-exclusion chromatography, LC × SEC) and infrared (IR) spectroscopy has been realized by means of an IR flow cell. The system has been assessed by the functional-group analysis of a series of

Disease specific stress of tumor patients at the beginning of radiotherapy. Effect on psychosocial support requirement; Krankheitsspezifische Belastungen von Tumorpatienten zu Beginn einer Strahlentherapie. Auswirkungen auf den psychosozialen Betreuungsbedarf

Energy Technology Data Exchange (ETDEWEB)

Sehlen, S.; Hollenhorst, H.; Schymura, B.; Firsching, M.; Duehmke, E. [Ludwig-Maximilians-Univ., Muenchen (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Aydemir, U. [Inst. fuer Biometrie und Epidemiologie, Klinikum Grosshadern, Ludwig-Maximilians-Univ., Muenchen (Germany); Herschbach, P. [Technische Univ. Muenchen (Germany). Inst. und Poliklinik fuer Psychosomatische Medizin, Psychotherapie und medizinische Psychologie

2001-10-01

requirement. (orig.) [German] Hintergrund: Die Radiotherapie bringt Tumorpatienten in eine besondere Lebenssituation, in der sie eine Reihe von unterschiedlichen Faktoren ausgesetzt werden, deren Auspraegung weitgehend unbekannt ist. Intention dieser Querschnittsstudie war es, erstmals systematisch die spezifischen Belastungen von Tumorpatienten zu Beginn einer Strahlentherapie aufzuzeigen und einen belastungsabhaengigen Betreuungswunsch zu erheben mit dem Ziel einer Belastungsreduktion und Verbesserung von Lebensqualitaet und Compliance waehrend einer radioonkologischen Behandlung. Patienten und Methoden: 732 Patienten wurden zunaechst in die Studie aufgenommen, von denen 446 (60,9%) die Einschlusskriterien erfuellten (Ablehnung 21,0%, Karnofsky-Index 6,6%, organisatorische Probleme 3,4%, Sprachbarrieren 3,0%, kognitive Einschraenkung 2,6%, Tod 2,5%). Folgende Erhebungsinstrumente gingen in die Auswertung zu Beginn der Strahlentherapie ein: medizinische und soziodemographische Daten, Lebenssituation (LS), Fragebogen zur Belastung von Krebspatienten (FBK), selbst definierter Betreuungswunsch (BB). 262 Maenner und 184 Frauen (medianes Alter 60,0 Jahre) mit unterschiedlichen Diagnosen wurden untersucht. Ergebnisse: Auf Skalenebene des Fragebogens zur Belastung von Krebspatienten zeigte sich vor allem eine Belastung durch Einschraenkung der Leistungsfaehigkeit, Angst und Schmerz. Frauen hatten signifikant hoehere Belastungswerte in den Bereichen Schmerz (p=0,016) und Angst (p=0,009), Patienten unter 45 Jahren im Bereich Information (p=0,002) und Patienten zwischen 45 und 60 Jahren in den Bereichen Angst (p=0,002) und Gesamtbelastung (p=0,003). Patientinnen mit einem Mammakarzinom waren am staerksten belastet. Der Anteil von stark belasteten Patienten war in den Skalen Leistungsfaehigkeit (43%) und Angst (40%) am hoechsten. Es bestand ein signifikanter Zusammenhang zwischen hoher Belastung und hohem Betreuungswunsch (insbesondere nach Arzt-/Psychologengespraechen und Information

Demonstration of conjugated dopamine in monkey CSF by gas chromatography-mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Elchisak, M A; Powers, K H; Ebert, M H

1982-09-01

A method for measuring unconjugated and conjugated dopamine in body tissues and fluids is described. Conjugated dopamine was hydrolyzed in acid to unconjugated dopamine, separated from the sample matrix by alumina chromatography, and assayed by gas chromatography-mass spectrometry. Conjugated dopamine was detected in greater concentrations than unconjugated dopamine in CSF taken from lateral ventricle or thecal sac of the Rhesus monkey. Haloperidol administration did not increase the levels of conjugated dopamine in lumbar CSF.

Analysis of Biological Interactions by Affinity Chromatography: Clinical and Pharmaceutical Applications.

Science.gov (United States)

Hage, David S

2017-06-01

The interactions between biochemical and chemical agents in the body are important in many clinical processes. Affinity chromatography and high-performance affinity chromatography (HPAC), in which a column contains an immobilized biologically related binding agent, are 2 methods that can be used to study these interactions. This review presents various approaches that can be used in affinity chromatography and HPAC to characterize the strength or rate of a biological interaction, the number and types of sites that are involved in this process, and the interactions between multiple solutes for the same binding agent. A number of applications for these methods are examined, with an emphasis on recent developments and high-performance affinity methods. These applications include the use of these techniques for fundamental studies of biological interactions, high-throughput screening of drugs, work with modified proteins, tools for personalized medicine, and studies of drug-drug competition for a common binding agent. The wide range of formats and detection methods that can be used with affinity chromatography and HPAC for examining biological interactions makes these tools attractive for various clinical and pharmaceutical applications. Future directions in the development of small-scale columns and the coupling of these methods with other techniques, such as mass spectrometry or other separation methods, should continue to increase the flexibility and ease with which these approaches can be used in work involving clinical or pharmaceutical samples. © 2016 American Association for Clinical Chemistry.

Tutorial: simulating chromatography with Microsoft Excel Macros.

Science.gov (United States)

Kadjo, Akinde; Dasgupta, Purnendu K

2013-04-22

Chromatography is one of the cornerstones of modern analytical chemistry; developing an instinctive feeling for how chromatography works will be invaluable to future generation of chromatographers. Specialized software programs exist that handle and manipulate chromatographic data; there are also some that simulate chromatograms. However, the algorithm details of such software are not transparent to a beginner. In contrast, how spreadsheet tools like Microsoft Excel™ work is well understood and the software is nearly universally available. We show that the simple repetition of an equilibration process at each plate (a spreadsheet row) followed by discrete movement of the mobile phase down by a row, easily automated by a subroutine (a "Macro" in Excel), readily simulates chromatography. The process is readily understood by a novice. Not only does this permit simulation of isocratic and simple single step gradient elution, linear or multistep gradients are also easily simulated. The versatility of a transparent and easily understandable computational platform further enables the simulation of complex but commonly encountered chromatographic scenarios such as the effects of nonlinear isotherms, active sites, column overloading, on-column analyte degradation, etc. These are not as easily simulated by available software. Views of the separation as it develops on the column and as it is seen by an end-column detector are both available in real time. Excel 2010™ also permits a 16-level (4-bit) color gradation of numerical values in a column/row; this permits visualization of a band migrating down the column, much as Tswett may have originally observed, but in a numerical domain. All parameters of relevance (partition constants, elution conditions, etc.) are readily changed so their effects can be examined. Illustrative Excel spreadsheets are given in the Supporting Information; these are easily modified by the user or the user can write his/her own routine. Copyright

Purification of bacteriocins using size-exclusion chromatography

Directory of Open Access Journals (Sweden)

Vivek K. Bajpai

2016-06-01

Full Text Available The bacteriocin purification involves following main steps. a. Extraction of cell-free-supernatant of bacteria. b. Ammonium sulfate precipitation. c. Dialysis. d. Diafiltration using PVP and e. Size-exclusion chromatography. However, depending on the nature of work, the compound could be further analyzed by reverse-phase HPLC, NMR, mass spectrometry and sequencing.

Gas chromatography mass spectrometry : key technology in metabolomics

NARCIS (Netherlands)

Koek, Maud Marijtje

2009-01-01

Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues. Gas chromatography coupled to mass spectrometry (GC-MS) is very suitable for metabolomics analysis, as it combines high separation power with

Extending the molecular application range of gas chromatography

NARCIS (Netherlands)

Kaal, E.; Janssen, H.-G.

2008-01-01

Gas chromatography is an important analytical technique for qualitative and quantitative analysis in a wide range of application areas. It is fast, provides a high peak capacity, is sensitive and allows combination with a wide range of selective detection methods including mass spectrometry.

Application of liquid column chromatography to preconcentration, separation and determination of platinum metals

International Nuclear Information System (INIS)

Alimarin, I.P.; Basova, E.M.; Bol'shova, T.A.; Ivanov, V.M.

1986-01-01

Separation and determination of platimum metals using the methods of adsorption, ion-pair, ion-exchange, distributing and sieve chromatography are discussed in the review of literature in 1971-1984. Separation and determination of metals as chelates using the method of adsorption and ion-pair chromatograpy are noted to be most perspective directions of developing highly effective liquid chromatography of inorganic systems

Protein separations using enhanced-fluidity liquid chromatography.

Science.gov (United States)

Bennett, Raffeal; Olesik, Susan V

2017-11-10

Enhanced-fluidity liquid chromatography (EFLC) methods using methanol/H 2 O/CO 2 and hydrophilic interaction liquid chromatography (HILIC) were explored for the separation of proteins and peptides. EFLC is a separation mode that uses a mobile phase made of conventional solvents combined with liquid carbon dioxide (CO 2 ) in subcritical conditions. The addition of liquid CO 2 enhances diffusivity and decreases viscosity while maintaining mixture polarity, which typically results in reduced time of analysis. TFA additive and elevated temperature were leveraged as key factors in the separation of a 13-analyte intact protein mixture in under 5min. Under these conditions EFLC showed modest improvement in terms of peak asymmetry and analysis time over the competing ACN/H 2 O separation. Protein analytes detected by electrospray ionization - quadrupole time of flight, were shown to be unaffected by the addition of CO 2 in the mobile phase. Herein, the feasibility of separating hydrophilic proteins up to 80kDa (with transferrin) is demonstrated for CO 2 -containing mobile phases. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of new heterogeneous catalysts for the decomposition of methanol into hydrogen and carbon monoxide applying high throughput methods; Entwicklung neuer heterogener Katalysatoren zur Spaltung von Methanol in Wasserstoff und Kohlenmonoxid mittels Hochdurchsatz-Methoden

Energy Technology Data Exchange (ETDEWEB)

Weiss, Torsten

2008-07-11

The topic of this thesis has been the development of new heterogeneous catalysts for the decomposition of methanol into hydrogen and carbon monoxide. As an important constraint here, the content of noble metals of the catalysts should be as low as possible. High-throughput-methods were applied in some of the syntheses and experiments to accelerate the development, as, for example, the use of liquid based sol-gel syntheses and the examination of catalyst libraries by spatial resolution gas chromatography. This screening technique allowed to test up to 207 different substances during one single experiment. Then, different combinatorial strategies were applied. First, these methods led to a highly active and stable catalyst in the ternary system of Cu-Ni-Zn, which showed high conversion and selectivity comparable to an industrial reference catalyst. Its activity during an 18 hour long term run was constant in contrast to the reference. Second, an additional approach starting from a broader variety of elements led to a Ce- Ru- and to a Cr-Ru-catalyst. Both of them were highly active in short term experiments, but lost their outstanding performances during long term runs. (orig.) [German] Die vorliegende Arbeit befasste sich mit der Entwicklung neuer heterogener Katalysatoren fuer die Spaltung von Methanol zu Wasserstoff und Kohlenmonoxid, die einen moeglichst geringen Gehalt an Edelmetallen aufweisen sollten. Um diesen Prozess zu beschleunigen, wurden in einem Teil der Synthesen und Experimente Hochdurchsatzmethoden verwendet. Neben der Roboter gestuetzten Sol-Gel-Synthese umfasste dies die Untersuchung von Katalysatorbibliotheken mittels ortsaufgeloester Gaschromatographie, die es ermoeglichte, in einem Experiment bis zu 207 verschiedene Substanzen auf ihre katalytische Aktivitaet zu testen. Unter Anwendung verschiedener kombinatorischer Strategien wurde zunaechst ein sehr aktiver und stabiler Katalysator im ternaeren Cu-Ni-Zn-System entdeckt. Neben Umsaetzen und

Recent progress of chiral stationary phases for separation of enantiomers in gas chromatography.

Science.gov (United States)

Xie, Sheng-Ming; Yuan, Li-Ming

2017-01-01

Chromatography techniques based on chiral stationary phases are widely used for the separation of enantiomers. In particular, gas chromatography has developed rapidly in recent years due to its merits such as fast analysis speed, lower consumption of stationary phases and analytes, higher column efficiency, making it a better choice for chiral separation in diverse industries. This article summarizes recent progress of novel chiral stationary phases based on cyclofructan derivatives and chiral porous materials including chiral metal-organic frameworks, chiral porous organic frameworks, chiral inorganic mesoporous materials, and chiral porous organic cages in gas chromatography, covering original research papers published since 2010. The chiral recognition properties and mechanisms of separation toward enantiomers are also introduced. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiogas chromatography mass spectrometry in the selected ion monitoring mode

International Nuclear Information System (INIS)

Doerfler, D.L.; Rosenblum, E.R.; Malloy, J.M.; Naworal, J.D.; McManus, I.R.; Campbell, I.M.

1980-01-01

The value of selected ion monitoring in analyzing biological radio isotope incorporation experiments by radiogas chromatography mass spectrometry is illustrated with reference to the biosynthesis of the mycotoxin mycophenolic acid in Penicillium brevicompactum and the mode of action of the anticholesterolemic drug 20,25-diazacholesterol. Both examples used 1-[ 14 C]acetate precursors. It is shown that the increased sensitivity and specificity of the selected ion monitoring mode detector permits straightforward detection and identification of the relatively small cellular pools associated with metabolic intermediates. The computer program RADSIM is described. Problems that still exist in using radiogas gas chromatography mass spectrometry technology to analyse isotope incorporation experiments are discussed. (author)

High-performance liquid chromatography of oligoguanylates at high pH

Science.gov (United States)

Stribling, R.; Deamer, D. (Principal Investigator)

1991-01-01

Because of the stable self-structures formed by oligomers of guanosine, standard high-performance liquid chromatography techniques for oligonucleotide fractionation are not applicable. Previously, oligoguanylate separations have been carried out at pH 12 using RPC-5 as the packing material. While RPC-5 provides excellent separations, there are several limitations, including the lack of a commercially available source. This report describes a new anion-exchange high-performance liquid chromatography method using HEMA-IEC BIO Q, which successfully separates different forms of the guanosine monomer as well as longer oligoguanylates. The reproducibility and stability at high pH suggests a versatile role for this material.

Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry.

Science.gov (United States)

Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M

2017-09-01

Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Changes in the basic experimental parameters of capillary gas chromatography in the 20th century.

Science.gov (United States)

Berezkin, V G; Viktorova, E N

2003-01-24

Studies of qualitative changes in capillary gas chromatography are of significant practical and scientific interest. This paper analyzes the evolution of the most important experimental chromatographic parameters over the last three decades and is based on the use of a new approach to scientometrical research that is referred to as applied scientometry. One essential feature of this approach is that it looks at the entire contents of each paper rather than only taking account its title, abstract. and references (as is typical for conventional scientometry). In this paper, we monitor how the most important chromatographic parameters, such as column length and diameter, layer thickness, stationary liquid phases, separation temperature mode. etc., have been evolving over the period 1970-2000. We used data from the following journals: Chromatographia, Journal of Chromatography, and Journal of High Resolution Chromatography and Chromatography Communications.

A generalized theory of chromatography and multistep liquid extraction

Science.gov (United States)

Chizhkov, V. P.; Boitsov, V. N.

2017-03-01

A generalized theory of chromatography and multistep liquid extraction is developed. The principles of highly efficient processes for fine preparative separation of binary mixture components on a fixed sorbent layer are discussed.

Radioactivity monitor for high-performance liquid chromatography

International Nuclear Information System (INIS)

Reeve, D.R.; Crozier, A.

1977-01-01

The coupling of a homogeneous radioactivity monitor to a liquid chromatograph involves compromises between the sensitivity of the monitor and the resolution and speed of analysis of the chromatograph. The theoretical relationships between these parameters are considered and expressions derived which make it possible to calculate suitable monitor operating conditions for most types of high-performance liquid chromatography

Multiresidue analysis of pesticides in olive oil by gel permeation chromatography followed by gas chromatography-tandem mass-spectrometric determination

International Nuclear Information System (INIS)

Sanchez, Andres Garcia; Martos, Natividad Ramos; Ballesteros, Evaristo

2006-01-01

A method for the multiresidue analysis of olive oil samples for 26 pesticides is proposed. Residual pesticides are extracted from oil using an n-hexane/acetonitrile mixture, extracts being cleaned-up by gel permeation chromatography (GPC) for analysis by gas chromatography-tandem mass spectrometry (GC-MS/MS). Electron ionization and chemical ionization are employed in a single analysis for the determination of pesticides. Pesticide recoveries from virgin and refined olive oil spiked with 10, 100 and 250 μg/kg concentrations of the pesticides ranged from 83.8 to 110.3%. The proposed method features good sensitivity: its limits of quantification are low enough to allow pesticide residues to be determined at concentrations below the maximum residue levels legally accepted. The precision, expressed as relative standard deviation, ranges from 4.93 to 8.11%. Applicability was tested on 40 olive oil samples. Several pesticides were detected in most of the virgin olive oil samples. By contrast, refined olive samples contained few pesticides, and only endosulfan sulphate was detected in all

Ultra high performance liquid chromatography of seized drugs

NARCIS (Netherlands)

Lurie, I.S.

2010-01-01

The primary goal of this thesis is to investigate the use of ultra high performance liquid chromatography (UHPLC) for the analysis of seized drugs. This goal was largely achieved and significant progress was made in achieving improved separation and detection of drugs of forensic interest.

Dielectrokinetic chromatography devices

Science.gov (United States)

Chirica, Gabriela S; Fiechtner, Gregory J; Singh, Anup K

2014-12-16

Disclosed herein are methods and devices for dielectrokinetic chromatography. As disclosed, the devices comprise microchannels having at least one perturber which produces a non-uniformity in a field spanning the width of the microchannel. The interaction of the field non-uniformity with a perturber produces a secondary flow which competes with a primary flow. By decreasing the size of the perturber the secondary flow becomes significant for particles/analytes in the nanometer-size range. Depending on the nature of a particle/analyte present in the fluid and its interaction with the primary flow and the secondary flow, the analyte may be retained or redirected. The composition of the primary flow can be varied to affect the magnitude of primary and/or secondary flows on the particles/analytes and thereby separate and concentrate it from other particles/analytes.

Systematic Comparison of Reverse Phase and Hydrophilic Interaction Liquid Chromatography Platforms for the Analysis of N-linked Glycans

Science.gov (United States)

Walker, S. Hunter; Carlisle, Brandon C.; Muddiman, David C.

2013-01-01

Due to the hydrophilic nature of glycans, reverse phase chromatography has not been widely used as a glycomic separation technique coupled to mass spectrometry. Other approaches such as hydrophilic interaction chromatography and porous graphitized carbon chromatography are often employed, though these strategies frequently suffer from decreased chromatographic resolution, long equilibration times, indefinite retention, and column bleed. Herein, it is shown that through an efficient hydrazone formation derivatization of N-linked glycans (∼4 hr of additional sample preparation time which is carried out in parallel), numerous experimental and practical advantages are gained when analyzing the glycans by online reverse phase chromatography. These benefits include an increased number of glycans detected, increased peak capacity of the separation, and the ability to analyze glycans on the identical liquid chromatography-mass spectrometry platform commonly used for proteomic analyses. The data presented show that separation of derivatized N-linked glycans by reverse phase chromatography significantly out-performs traditional separation of native or derivatized glycans by hydrophilic interaction chromatography. Furthermore, the movement to a more ubiquitous separation technique will afford numerous research groups the opportunity to analyze both proteomic and glycomic samples on the same platform with minimal time and physical change between experiments, increasing the efficiency of ‘multi-omic’ biological approaches. PMID:22954204

High-capacity cation-exchange column for enhanced resolution of adjacent peaks of cations in ion chromatography.

Science.gov (United States)

Rey, M A

2001-06-22

One of the advantages of ion chromatography [Anal Chem. 47 (1975) 1801] as compared to other analytical techniques is that several ions may be analyzed simultaneously. One of the most important contributions of cation-exchange chromatography is its sensitivity to ammonium ion, which is difficult to analyze by other techniques [J. Weiss, in: E.L. Johnson (Ed.), Handbook of Ion Chromatography, Dionex, Sunnyvale, CA, USA]. The determination of low concentrations of ammonium ion in the presence of high concentrations of sodium poses a challenge in cation-exchange chromatography [J. Weiss, Ion Chromatography, VCH, 2nd Edition, Weinheim, 1995], as both cations have similar selectivities for the common stationary phases containing either sulfonate or carboxylate functional groups. The task was to develop a new cation-exchange stationary phase (for diverse concentration ratios of adjacent peaks) to overcome limitations experienced in previous trails. Various cation-exchange capacities and column body formats were investigated to optimize this application and others. The advantages and disadvantages of two carboxylic acid columns of different cation-exchange capacities and different column formats will be discussed.

On-line hyphenation of centrifugal partition chromatography and high pressure liquid chromatography for the fractionation of flavonoids from Hippophaë rhamnoides L. berries.

Science.gov (United States)

Michel, Thomas; Destandau, Emilie; Elfakir, Claire

2011-09-09

Centrifugal Partition Chromatography (CPC), a liquid-liquid preparative chromatography using two immiscible solvent systems, benefits from numerous advantages for the separation or purification of synthetic or natural products. This study presents the on-line hyphenation of CPC-Evaporative Light Scattering Detector (CPC-ELSD) with High Performance Liquid Chromatography-UV (HPLC-UV) for the fractionation of flavonols from a solvent-free microwave extract of sea buckthorn (Hippophaë rhamnoides L., Elaeagnaceae) berries. An Arizona G system was used for the fractionation of flavonoids by CPC and a fused core Halo C18 column allowed the on-line analyses of collected fractions by HPLC. The on-line CPC/HPLC procedure allowed the simultaneous fractionation step at preparative scale combined with the HPLC analyses which provide direct fingerprint of collected fractions. Thus the crude extract was simplified and immediate information on the composition of fractions could be obtained. Furthermore, this methodology reduced the time of post-fractionation steps and facilitated identification of main molecules by Mass Spectrometry (MS). Rutin, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, quercetin-3-O-glucoside, isorhamnetin-rhamnoside, quercetin and isorhamnetin were identified. CPC-ELSD/HPLC-UV could be considered as a high-throughput technique for the guided fractionation of bioactive natural products from complex crude extracts. Copyright © 2011 Elsevier B.V. All rights reserved.

Plasma wave detection in laser spectroscopy and gas chromatography

International Nuclear Information System (INIS)

Franzke, J.; Irmer, A. von; Veza, D.; Niemax, K.

1995-01-01

Frequency changes of plasma oscillations in low-pressure discharges are used for sensitive detection of atomic or molecular trace gases. Analyte selectivity can be either obtained by resonant laser excitation or by gas chromatography

Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

Science.gov (United States)

Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

Single-column ion chromatography with determination of hydrazoic acid produced in spent nuclear fuel reprocessing

International Nuclear Information System (INIS)

Ma Guilan; Tan Shuping

2006-01-01

The reaction of hydrazine and its derivative with ammonium metavanadate may produce hydrazoic acid (HN 3 ). A single-column ion chromatography is used for the determination of HN 3 after neutralizing the rest acid in the sample with sodium hydroxide. Chromatography separation of HN 3 is carried out on a 25 cm x 0.46 cm (inside diameter) stainless steel column packed with Vydac IC302 ion Chromatography packing. The eluent is 1 mmol/L o-phthalic acid, and the ion is detected by conductivity detector. The detection limit in the presence chromatography is 5 μg/mL, the linear range is from 5 to 201 μg/mL, the linear correlation coefficient is 0.9994, respectively. The analysis accuracy is 2% for standard sample, and the detection limit is 51 μg/mL for HN 3 in the real sample. (authors)

Polarity-based fractionation in proteomics: hydrophilic interaction vs reversed-phase liquid chromatography.

Science.gov (United States)

Jafari, M; Mirzaie, M; Khodabandeh, M; Rezadoost, H; Ghassempour, A; Aboul-Enein, H Y

2016-07-01

During recent decades, hydrophilic interaction liquid chromatography (HILIC) ahs been introduced to fractionate or purify especially polar solutes such as peptides and proteins while reversed-phase liquid chromatography (RPLC) is also a common strategy. RPLC is also a common dimension in multidimensional chromatography. In this study, the potential of HILIC vs RPLC chromatography was compared for proteome mapping of human peripheral blood mononuclear cell extract. In HILIC a silica-based stationary phase and for RPLC a C18 column were applied. Then separated proteins were eluted to an ion trap mass spectrometry system. Our results showed that the HILIC leads to more proteins being identified in comparison to RPLC. Among the total 181 identified proteins, 56 and 38 proteins were fractionated specifically by HILIC and RPLC, respectively. In order to demonstrate this, the physicochemical properties of identified proteins such as polarity and hydrophobicity were considered. This analysis indicated that polarity may play a major role in the HILIC separation of proteins vs RPLC. Using gene ontology enrichment analysis, it was also observed that differences in physicochemical properties conform to the cellular compartment and biological features. Finally, this study highlighted the potential of HILIC and the great orthogonality of RPLC in gel-free proteomic studies. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Characterization of the pigment fraction in sweet bell peppers (Capsicum annuum L.) harvested at green and overripe yellow and red stages by offline multidimensional convergence chromatography/liquid chromatography-mass spectrometry.

Science.gov (United States)

Bonaccorsi, Ivana; Cacciola, Francesco; Utczas, Margita; Inferrera, Veronica; Giuffrida, Daniele; Donato, Paola; Dugo, Paola; Mondello, Luigi

2016-09-01

Offline multidimensional supercritical fluid chromatography combined with reversed-phase liquid chromatography was employed for the carotenoid and chlorophyll characterization in different sweet bell peppers (Capsicum annuum L.) for the first time. The first dimension consisted of an Acquity HSS C18 SB (100 × 3 mm id, 1.8 μm particles) column operated with a supercritical mobile phase in an ultra-performance convergence chromatography system, whereas the second dimension was performed in reversed-phase mode with a C30 (250 × 4.6 mm id, 3.0 μm particles) stationary phase combined with photodiode array and mass spectrometry detection. This approach allowed the determination of 115 different compounds belonging to chlorophylls, free xanthophylls, free carotenes, xanthophyll monoesters, and xanthophyll diesters, and proved to be a significant improvement in the pigments determination compared to the conventional one-dimensional liquid chromatography approach so far applied to the carotenoid analysis in the studied species. Moreover, the present study also aimed to investigate and to compare the carotenoid stability and composition in overripe yellow and red bell peppers collected directly from the plant, thus also evaluating whether biochemical changes are linked to carotenoid degradation in the nonclimacteric investigated fruits, for the first time. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mallow carotenoids determined by high-performance liquid chromatography

Science.gov (United States)

Mallow (corchorus olitorius) is a green vegetable, which is widely consumed either fresh or dry by Middle East population. This study was carried out to determine the contents of major carotenoids quantitatively in mallow, by using a High Performance Liquid Chromatography (HPLC) equipped with a Bis...

Investigation of Pinus mugo essential oil oxygenated fraction by combined use of gas chromatography and dry column chromatography.

Science.gov (United States)

A, M B; Coran, S A; Giannellini, V; Vincieri, F F; Moneti, G

1981-09-01

The oxygenated compounds of Pinus mugo Turra essential oil were investigated by a combination of GC and dry column chromatography (DCC) coordinated by GC data processing. The collected data resulted in a bar graph ("normalized" gas chromatogram) giving the RRT's and relative amounts of 68 components; 38 of them were identified by MS and IR. The described procedure may be used for essential oil analysis in general.

Purification of bone morphogenetic protein-2 from refolding mixtures using mixed-mode membrane chromatography.

Science.gov (United States)

Gieseler, Gesa; Pepelanova, Iliyana; Stuckenberg, Lena; Villain, Louis; Nölle, Volker; Odenthal, Uwe; Beutel, Sascha; Rinas, Ursula; Scheper, Thomas

2017-01-01

In this study, we present the development of a process for the purification of recombinant human bone morphogenetic protein-2 (rhBMP-2) using mixed-mode membrane chromatography. RhBMP-2 was produced as inclusion bodies in Escherichia coli. In vitro refolding using rapid dilution was carried out according to a previously established protocol. Different membrane chromatography phases were analyzed for their ability to purify BMP-2. A membrane phase with salt-tolerant properties resulting from mixed-mode ligand chemistry was able to selectively purify BMP-2 dimer from refolding mixtures. No further purification or polishing steps were necessary and high product purity was obtained. The produced BMP-2 exhibited a biological activity of 7.4 × 10 5  U/mg, comparable to commercial preparations. Mixed-mode membrane chromatography can be a valuable tool for the direct purification of proteins from solutions with high-conductivity, for example refolding buffers. In addition, in this particular case, it allowed us to circumvent the use of heparin-affinity chromatography, thus allowing the design of an animal-component-free process.

Separation of Poly(styrene-block-t-butyl methacrylate) Copolymers by Various Liquid Chromatography Techniques

Science.gov (United States)

Šmigovec Ljubič, Tina; Pahovnik, David; Žigon, Majda; Žagar, Ema

2012-01-01

The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length and t-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy. PMID:22489207

Determination of basic azaarenes and polynuclear aromatic hydrocarbons in airborne particulate matter by gas chromatography

DEFF Research Database (Denmark)

Nielsen, Torben; Clausen, Peraxel; Jensen, Finn Palmgren

1986-01-01

phase (adjusted to pH 14 with potassium hydroxide) with dichloromethane, and determined by capillary gas chromatography (g.c.) with a nitrogen-sensitive detector. The PAH in the toluene phase are isolated by means of semipreparative high-performance liquid chromatography and liquid-liquid extraction...

Gas chromatography-mass spectrometry and high-performance liquid chromatographic analyses of thermal degradation products of common plastics

OpenAIRE

Pacakova, V.; Leclercq, P.A.

1991-01-01

The thermo-oxidation of five commonly used materials, namely low-density polyethylene, retarded polyethylene, paper with a polyethylene foil, a milk package and filled polypropylene, was studied. Capillary gas chromatography and gas chromatography-mass spectrometry were used to analyze the volatile degradation products, while high-performance liquid chromatography was employed to measure polycyclic aromatic hydrocarbons. The results are discussed from the point of view of toxicity of the prod...

Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

Directory of Open Access Journals (Sweden)

Pia Sala

2015-04-01

Full Text Available A novel liquid chromatography-mass spectrometry (LC-MS approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI coupled to hydrophilic interaction liquid chromatography (HILIC was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.

Quality evaluation of moluodan concentrated pill using high-performance liquid chromatography fingerprinting coupled with chemometrics.

Science.gov (United States)

Tao, Lingyan; Zhang, Qing; Wu, Yongjiang; Liu, Xuesong

2016-12-01

In this study, a fast and effective high-performance liquid chromatography method was developed to obtain a fingerprint chromatogram and quantitative analysis simultaneously of four indexes including gallic acid, chlorogenic acid, albiflorin and paeoniflorin of the traditional Chinese medicine Moluodan Concentrated Pill. The method was performed by using a Waters X-bridge C 18 reversed phase column on an Agilent 1200S high-performance liquid chromatography system coupled with diode array detection. The mobile phase of the high-performance liquid chromatography method was composed of 20 mmol/L phosphate solution and acetonitrile with a 1 mL/min eluent velocity, under a detection temperature of 30°C and a UV detection wavelength of 254 nm. After the methodology validation, 16 batches of Moluodan Concentrated Pill were analyzed by this high-performance liquid chromatography method and both qualitative and quantitative evaluation results were achieved by similarity analysis, principal component analysis and hierarchical cluster analysis. The results of these three chemometrics were in good agreement and all indicated that batch 10 and batch 16 showed significant differences with the other 14 batches. This suggested that the developed high-performance liquid chromatography method could be applied in the quality evaluation of Moluodan Concentrated Pill. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immunoaffinity chromatography for the sample pretreatment of Taxus plant and cell extracts prior to analysis of taxanes by high-performance liquid chromatography

NARCIS (Netherlands)

Theodoridis, G; Haasnoot, W; Schilt, R; Jaziri, M; Diallo, B; Papadoyannis, IN; de Jong, GJ; Cazemier, G.

2002-01-01

The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III), paclitaxel's main precursor in plant, were characterised by enzymed-linked

Therapeutic drug monitoring of nevirapine in saliva in Uganda using high performance liquid chromatography and a low cost thin-layer chromatography technique

NARCIS (Netherlands)

Lamorde, M.; Fillekes, Q.; Sigaloff, K.; Kityo, C.; Buzibye, A.; Kayiwa, J.; Merry, C.; Nakatudde-Katumba, L.; Burger, D.M.; Wit, T.F. de

2014-01-01

BACKGROUND: In resource limited settings access to laboratory monitoring of HIV treatment is limited and therapeutic drug monitoring is generally unavailable. This study aimed to evaluate nevirapine concentrations in saliva using low-cost thin-layer chromatography (TLC) and nevirapine concentrations

Therapeutic drug monitoring of nevirapine in saliva in Uganda using high performance liquid chromatography and a low cost thin-layer chromatography technique

NARCIS (Netherlands)

Lamorde, Mohammed; Fillekes, Quirine; Sigaloff, Kim; Kityo, Cissy; Buzibye, Allan; Kayiwa, Joshua; Merry, Concepta; Nakatudde-Katumba, Lillian; Burger, David; Rinke de Wit, Tobias F.

2014-01-01

In resource limited settings access to laboratory monitoring of HIV treatment is limited and therapeutic drug monitoring is generally unavailable. This study aimed to evaluate nevirapine concentrations in saliva using low-cost thin-layer chromatography (TLC) and nevirapine concentrations in plasma

Toward ideal separation by size-exclusion chromatography

Czech Academy of Sciences Publication Activity Database

Netopilík, Miloš

2017-01-01

Roč. 1487, 3 March (2017), s. 139-146 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GC17-04258J Grant - others:OPPK(XE) CZ.2.16/3.1.00/24504 Institutional support: RVO:61389013 Keywords : size-exclusion chromatography * separation mechanism * band broadening function Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.981, year: 2016

Gas chromatography in blood carbon monoxide monitoring

Energy Technology Data Exchange (ETDEWEB)

Drasche, H.; Funk, L.; Herbolsheimer, R.

1975-05-01

A description of a gas chromatography method for monitoring blood carboxyhaemoglobin (HbCO) levels in a very small quantity (100 mcl) of capillary blood: reagents and apparatus, procedures, calculation of results. To calculate HbCO content, an aliquot portion of water-diluted blood is saturated with CO; this saturation obviates the need to determine the haemoglobin or iron blood levels.

Applications of the gas chromatography in the nuclear science and technology

International Nuclear Information System (INIS)

Gasco Sanchez, L.

1972-01-01

This paper is a review on the applications of the gas chromatography in the nuclear science and technology published up to December 1971. Its contents has been classified under the following heads; I) Radiogaschromatography, II) Isotope separation, III) Preparation of labelled molecules, IV) Nuclear fuel cycle, V) Nuclear reactor technology, VI) Irradiation chemistry, VIl) Separation of me tal compounds in gas phase, VIII) Applications of the gas chromatography carried out at the Junta de Energia Nuclear, Spain. Arapter VIII only includes the investigations carried out from January 1969 to December 1971. Previous investigations in this field has been published elsewhere. (Author)

Column chromatography as a useful step in purification of diatom pigments.

Science.gov (United States)

Tokarek, Wiktor; Listwan, Stanisław; Pagacz, Joanna; Leśniak, Piotr; Latowski, Dariusz

2016-01-01

Fucoxanthin, diadinoxanthin and diatoxanthin are carotenoids found in brown algae and most other heterokonts. These pigments are involved in photosynthetic and photoprotective reactions, and they have many potential health benefits. They can be extracted from diatom Phaeodactylum tricornutum by sonication, extraction with chloroform : methanol and preparative thin layer chromatography. We assessed the utility of an additional column chromatography step in purification of these pigments. This novel addition to the isolation protocol increased the purity of fucoxanthin and allowed for concentration of diadinoxanthin and diatoxanthin before HPLC separation. The enhanced protocol is useful for obtaining high purity pigments for biochemical studies.

Identification of bound alcohols in soil humic acids by gas chromatography-mass spectrometry

OpenAIRE

Berthier , Gersende; Dou , Sen; Peakman , Torren; Lichtfouse , Eric

2000-01-01

International audience; Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to shed some light on their molecular structure, crop humic acids were cleaved by alkaline hydrolysis (KOH). The products were fractionated by thin layer chromatography to give mono-alcohols which were analysed as acetate derivatives by gas chromatography coupled to mass spectrometry. Linear alcohols, sterols, stanols and plant-derived triterpen...

Copolymerization preparation of cationic cyclodextrin chiral stationary phases for drug enantioseparation in chromatography

OpenAIRE

sprotocols

2015-01-01

Authors: Ren-Qi Wang, Teng-Teng Ong, Ke Huang, Weihua Tang & Siu-Choon Ng ### Abstract We described a facile and effective protocol wherein radical copolymerization is employed to covalently bond cationic β-cyclodextrin (β-CD) onto silica particles with extended linkage, resulting in a chiral stationary phase (IMPCSP) that can be used for the enantioseparation of racemic drugs in both high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). Starting ...

The application of extraction chromatography to the determination of radionuclides in biological and environmental samples

International Nuclear Information System (INIS)

Testa, C.; Delle Site, A.

1976-01-01

The paper describe the application of extraction chromatography to the determination of several alpha and beta emitters in biological and environmental samples. Both column extraction chromatography and batch extraction process have been used to isolate the radionuclides from the samples. The effect of several parameters (extractant concentration, support granulometry, stirring time, temperature, presence of a complexing agent) on the extraction and elution has been examined. The application of redox extraction chromatography is also described. A very simple and rapid determination of the activity retained on the column can be obtained by transferring the slurry to a counting vial and by adding the scintillation liquid for a direct detection of the α or β emission. The counting efficiencies obtained with this technique are compared with those obtained with ion exchange resins. The organic polymers used for the extraction chromatography give about 100% counting efficiency. The conventional ion exchange resin cannot be used to this purpose because of their strong light absorption. (T.G.)

Optimising the design and operation of semi-continuous affinity chromatography for clinical and commercial manufacture.

Science.gov (United States)

Pollock, James; Bolton, Glen; Coffman, Jon; Ho, Sa V; Bracewell, Daniel G; Farid, Suzanne S

2013-04-05

This paper presents an integrated experimental and modelling approach to evaluate the potential of semi-continuous chromatography for the capture of monoclonal antibodies (mAb) in clinical and commercial manufacture. Small-scale single-column experimental breakthrough studies were used to derive design equations for the semi-continuous affinity chromatography system. Verification runs with the semi-continuous 3-column and 4-column periodic counter current (PCC) chromatography system indicated the robustness of the design approach. The product quality profiles and step yields (after wash step optimisation) achieved were comparable to the standard batch process. The experimentally-derived design equations were incorporated into a decisional tool comprising dynamic simulation, process economics and sizing optimisation. The decisional tool was used to evaluate the economic and operational feasibility of whole mAb bioprocesses employing PCC affinity capture chromatography versus standard batch chromatography across a product's lifecycle from clinical to commercial manufacture. The tool predicted that PCC capture chromatography would offer more significant savings in direct costs for early-stage clinical manufacture (proof-of-concept) (∼30%) than for late-stage clinical (∼10-15%) or commercial (∼5%) manufacture. The evaluation also highlighted the potential facility fit issues that could arise with a capture resin (MabSelect) that experiences losses in binding capacity when operated in continuous mode over lengthy commercial campaigns. Consequently, the analysis explored the scenario of adopting the PCC system for clinical manufacture and switching to the standard batch process following product launch. The tool determined the PCC system design required to operate at commercial scale without facility fit issues and with similar costs to the standard batch process whilst pursuing a process change application. A retrofitting analysis established that the direct cost

Separation of Aeruginosin-865 from Cultivated Soil Cyanobacterium (Nostoc sp.) by Centrifugal Partition Chromatography combined with Gel Permeation Chromatography

Czech Academy of Sciences Publication Activity Database

Cheel, José; Minceva, M.; Urajová, Petra; Aslam, R.; Hrouzek, Pavel; Kopecký, Jiří

2015-01-01

Roč. 10, č. 10 (2015), s. 1719-1722 ISSN 1934-578X R&D Projects: GA MŠk EE2.3.30.0059; GA MŠk ED2.1.00/03.0110; GA MŠk LO1416 Institutional support: RVO:61388971 Keywords : Cyanobacteria * Aeruginosin-865 * Centrifugal partition chromatography Subject RIV: EE - Microbiology, Virology Impact factor: 0.884, year: 2015

Analysis of new psychoactive substances in human urine by ultra-high performance supercritical fluid and liquid chromatography: Validation and comparison.

Science.gov (United States)

Borovcová, Lucie; Pauk, Volodymyr; Lemr, Karel

2018-05-01

New psychoactive substances represent serious social and health problem as tens of new compounds are detected in Europe annually. They often show structural proximity or even isomerism, which complicates their analysis. Two methods based on ultra high performance supercritical fluid chromatography and ultra high performance liquid chromatography with mass spectrometric detection were validated and compared. A simple dilute-filter-and-shoot protocol utilizing propan-2-ol or methanol for supercritical fluid or liquid chromatography, respectively, was proposed to detect and quantify 15 cathinones and phenethylamines in human urine. Both methods offered fast separation (chromatography. Limits of detection in urine ranged from 0.01 to 2.3 ng/mL, except for cathinone (5 ng/mL) in supercritical fluid chromatography. Nevertheless, this technique distinguished all analytes including four pairs of isomers, while liquid chromatography was unable to resolve fluoromethcathinone regioisomers. Concerning matrix effects and recoveries, supercritical fluid chromatography produced more uniform results for different compounds and at different concentration levels. This work demonstrates the performance and reliability of supercritical fluid chromatography and corroborates its applicability as an alternative tool for analysis of new psychoactive substances in biological matrixes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Empirical Formula From Ion Exchange Chromatography and Colorimetry.

Science.gov (United States)

Johnson, Steven D.

1996-01-01

Presents a detailed procedure for finding an empirical formula from ion exchange chromatography and colorimetry. Introduces students to more varied techniques including volumetric manipulation, titration, ion-exchange, preparation of a calibration curve, and the use of colorimetry. (JRH)

Effect of pore size on performance of monolithic tube chromatography of large biomolecules.

Science.gov (United States)

Podgornik, Ales; Hamachi, Masataka; Isakari, Yu; Yoshimoto, Noriko; Yamamoto, Shuichi

2017-11-01

Effect of pore size on the performance of ion-exchange monolith tube chromatography of large biomolecules was investigated. Radial flow 1 mL polymer based monolith tubes of different pore sizes (1.5, 2, and 6 μm) were tested with model samples such as 20 mer poly T-DNA, basic proteins, and acidic proteins (molecular weight 14 000-670 000). Pressure drop, pH transient, the number of binding site, dynamic binding capacity, and peak width were examined. Pressure drop-flow rate curves and dynamic binding capacity values were well correlated with the nominal pore size. While duration of the pH transient curves depends on the pore size, it was found that pH duration normalized on estimated surface area was constant, indicating that the ligand density is the same. This was also confirmed by the constant number of binding site values being independent of pore size. The peak width values were similar to those for axial flow monolith chromatography. These results showed that it is easy to scale up axial flow monolith chromatography to radial flow monolith tube chromatography by choosing the right pore size in terms of the pressure drop and capacity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid chromatography - mass spectrometry analysis of pharmaceuticals

International Nuclear Information System (INIS)

Macasek, F.

2003-01-01

The drugs represent mostly non-volatile and thermally labile solutes, often available only in small amounts like it is in case of radiopharmaceuticals. Therefor, the favourable separation techniques for such compounds are HPLC, capillary electrophoresis and also TLC 1. Liquid chromatography with mass spectrometric detector (LC/MS) is especially powerful for their microanalysis. Mass spectrometry separating the ions in high vacuum was presumably used as detector for gas chromatography effluent but the on-line coupling with liquid eluant flow 0.1-1 mL/min is far more challenging. New types of ion sources were constructed for simultaneous removal of solvent and ionisation of solutes at atmospheric pressure (API). At present, a relatively wide choice of successfully designed commercial equipment is available either for small organic molecules and larger biomolecules (Perkin-Elmer, Agilent, Jeol, Bruker Daltonics, ThermoQuest, Shimadzu). The features of the LC/MS systems are presented. LC/MS as a new quality control tool for [F-18]fluorodeoxyglucose (FDG) radiopharmaceutical, which has became the most spread radiopharmaceutical for positron emission tomography (PET), was proposed. Other applications of the LC/MS are reviewed. (author)

A Simple Thin Layer Chromatography Method for Separation of Selected Natural Steroid Hormones

International Nuclear Information System (INIS)

Nowakowska, J.; Rudnicka-Litka, K.; Ciura, K.; Pikul, P.; Piotrowicz, J.

2015-01-01

Chromatographic properties of seven steroids: estrogens (β-estradiol and estrone), androgens (testosterone, methyltestosterone, trans-androsterone), progesterone and cholesterol have been studied by planar chromatography with usage of High Performance Thin Layer Chromatography (HPTLC) and Thin Layer Chromatography (TLC) plates. Normal, reversed and cyano-bonded silica stationary phases were tested with five binary mobile phases (acetonitrile-water, acetonitrile-DMSO, acetonitrile-methanol, acetone-petroleum ether, acetone-water) in which the concentration of organic modifier varied from 0 to 100 % (v/v). This study reports the optimization of steroid hormones separation. Principal Component Analysis (PCA) based on calculated molecular descriptors quantitatively differentiating solutes was performed in order to investigate the similarity and dissimilarity between tested compounds. The separation abilities of mobile and stationary phases were compared based on separation factor α. Chromatographic retention data and possible retention mechanisms also were discussed. (author)

[Separation and purification of the components in Trachelospermum jasminoides by two dimensional hydrophilic interaction liquid chromatography- reversed-phase liquid chromatography].

Science.gov (United States)

Jia, Youmei; Cai, Jianfeng; Xin, Huaxia; Feng, Jiatao; Fu, Yanhui; Fu, Qing; Jin, Yu

2017-06-08

A preparative two dimensional hydrophilic interaction liquid chromatography/reversed-phase liquid chromatography (Pre-2D-HILIC/RPLC) method was established to separate and purify the components in Trachelospermum jasminoides . The pigments and strongly polar components were removed from the crude extract after the active carbon decolorization and solid phase extraction processes. A Click XIon column (250 mm×20 mm, 10 μm) was selected as stationary phase and water-acetonitrile as mobile phases in the first dimensional HILIC. Finally, 15 fractions were collected under UV-triggered mode. In the second dimensional RPLC, a C18 column (250 mm×20 mm, 5 μm) was selected and water-acetonitrile was used as mobile phases. As a result, 14 compounds with high purity were obtained, which were further identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR). Finally, 11 lignan compounds and three flavonoid compounds were obtained. The method has a good orthogonality, and can improve the resolution and the peak capacity. It is significant for the separation of complex components from Trachelospermum jasminoides .

Gas chromatography x gas chromatography-time-of-flight mass spectrometry analysis and antibacterial activity of essential oil from Amomum xanthophlebium

International Nuclear Information System (INIS)

Masila, A.; Aminah, I.; Yaakob, W.A.; Nazlina, I.

2011-01-01

Essential oils of fresh leaves, stem, rhizomes and whole aromatic plants of Amomum xanthophlebium (Zingiberaceae) were obtained by hydro distillation. Percentage yields of the leaf, stem and whole plant oils were 0.0032, 0.0074 and 0.0021 % whereas the rhizome oil obtained was very little. Chemical components of each oil and their percentages were determined by Gas Chromatography x Gas Chromatography-Time-of-Flight Mass Spectrometry (GCxGC-TOFMS). Analysis of A. xanthophlebium oils showed that they were dominated by terpenes. Main components in the leaves were allo-aromadendrene (3.41 %), (±)-globulol (2.58 %) and rosifoliol (2.55 %); stem, α-terpineol (4.25 %), rosifoliol (2.41 %) and bingpian (2.27 %); rhizomes, viridiflorol (5.72 %), (±)-globulol (5.23 %) and α-cadinol (4.81 %); whole plants, eucalyptol (4.11 %), l-α-terpineol (2.88 %) and rosifoliol (2.82 %). The stem oil of A. xanthophlebium showed antibacterial activity against Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) at the minimum inhibitory concentration of 80 mg/ ml. (author)

High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.

Science.gov (United States)

Bohman, Ove; And Others

1982-01-01

Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)

Gas Chromatography-Mass Spectroscopic (GC-MS) Analysis of n ...

African Journals Online (AJOL)

1Department of Pharmacognosy and Phytotherapy, 2Department of Pharmaceutics and Pharmaceutical Technology, University of Port Harcourt, Nigeria ... tuber-regium (synonym Pleurotus tuber regium) using gas chromatography-mass spectroscopic (GC- ... Department of Plant Science and Biotechnology,. University of ...

Establishment of colloid gold immunity chromatography assay for cardiac troponin I (cTnI)

International Nuclear Information System (INIS)

Wang Dezhi; Chen Jiying; Qin Lili; Zhao Baojian; Zhang Chunming

2006-01-01

Objective: To establish the colloid gold Immunity chromatography assay for cardiac troponin I. Methods: To purify cTnI from human cardiac muscle and immunize rabbit with it. cTnI antibody of rabbit anti-human cardiac muscle has been prepared and colloid gold immunity chromatography assay was established by using immunity chromatography technology. Results: Anti-serum titles of cTnI were 1:100000, Ka=2.38 x 10 9 L/mol; Methodological index: Sensitivity: 5 ng/ml; Specificity: cTnI is no cross-reaction with cTnT, cTnC and CK-MB. conclusion: The assay is highly specific, quick and simple. It can be widely used for the early diagnosis of AMI and scientific research. (authors)

Online hyphenation of extraction, Sephadex LH-20 column chromatography, and high-speed countercurrent chromatography: A highly efficient strategy for the preparative separation of andrographolide from Andrographis paniculata in a single step.

Science.gov (United States)

Zhang, Ying-Qi; Wang, Shan-Shan; Han, Chao; Xu, Jin-Fang; Luo, Jian-Guang; Kong, Ling-Yi

2017-12-01

A novel isolation strategy, online hyphenation of ultrasonic extraction, Sephadex LH-20 column chromatography combined with high-speed countercurrent chromatography, was developed for pure compounds extraction and purification. Andrographolide from Andrographis paniculata was achieved only in a single step purification protocol via the present strategy. The crude powder was ultrasonic extracted and extraction was pumped into Sephadex LH-20 column directly to cut the nontarget fractions followed by the second-dimensional high-speed countercurrent chromatography, hyphenated by a six-port valve equipped at the post-end of Sephadex LH-20 column, for the final purification. The results yielded andrographolide with the amount of 1.02 mg and a purity of 98.5% in a single step, indicating that the present method is effective to harvest target compound from medicinal plant. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of γ-hydroxybutyrate in human urine samples by ion exclusion and ion exchange two-dimensional chromatography system.

Science.gov (United States)

Liu, Junwei; Deng, Zhifen; Zhu, Zuoyi; Wang, Yong; Wang, Guoqing; Sun, Yu-An; Zhu, Yan

2017-12-15

A two-dimensional ion chromatography system was developed for the determination of γ-hydroxybutyrate (GHB) in human urine samples. Ion exclusion chromatography was used in the first dimensional separation for elimination of urine matrices and detection of GHB above 10mgL -1 , ion exchange chromatography was used in the second dimensional separation via column-switching technique for detection of GHB above 0.08mgL -1 . Under the optimized chromatographic conditions, the ion exclusion and ion exchange chromatography separation system exhibited satisfactory repeatability (RSDchromatography system was convenient and practical for the determination of GHB in human urine samples. Copyright © 2017 Elsevier B.V. All rights reserved.

On-line coupling of size exclusion chromatography with mixed-mode liquid chromatography for comprehensive profiling of biopharmaceutical drug product.

Science.gov (United States)

He, Yan; Friese, Olga V; Schlittler, Michele R; Wang, Qian; Yang, Xun; Bass, Laura A; Jones, Michael T

2012-11-02

A methodology based on on-line coupling of size exclusion chromatography (SEC) with mixed-mode liquid chromatography (LC) has been developed. The method allows for simultaneous measurement of a wide range of components in biopharmaceutical drug products. These components include the active pharmaceutical ingredient (protein) and various kinds of excipients such as cations, anions, nonionic hydrophobic surfactant and hydrophilic sugars. Dual short SEC columns are used to separate small molecule excipients from large protein molecules. The separated protein is quantified using a UV detector at 280 nm. The isolated excipients are switched, online, to the Trinity P1 mixed-mode column for separation, and detected by an evaporative light scattering detector (ELSD). Using a stationary phase with 1.7 μm particles in SEC allows for the use of volatile buffers for both SEC and mix-mode separation. This facilitates the detection of different excipients by ELSD and provides potential for online characterization of the protein with mass spectrometry (MS). The method has been applied to quantitate protein and excipients in different biopharmaceutical drug products including monoclonal antibodies (mAb), antibody drug conjugates (ADC) and vaccines. Copyright © 2012 Elsevier B.V. All rights reserved.

On-line liquid chromatography-gas chromatography: A novel approach for the analysis of phytosterol oxidation products in enriched foods.

Science.gov (United States)

Scholz, Birgit; Wocheslander, Stefan; Lander, Vera; Engel, Karl-Heinz

2015-05-29

A novel methodology for the automated qualitative and quantitative determination of phytosterol oxidation products in enriched foods via on-line liquid chromatography-gas chromatography (LC-GC) was established. The approach is based on the LC pre-separation of acetylated phytosterols and their corresponding oxides using silica as stationary phase and a mixture of n-hexane/methyl tert-butyl ether/isopropanol as eluent. Two LC-fractions containing (i) 5,6-epoxy- and 7-hydroxyphytosterols, and (ii) 7-ketophytosterols are transferred on-line to the GC for the analysis of their individual compositions on a medium polar trifluoropropylmethyl polysiloxane capillary column. Thus, conventionally employed laborious off-line purification and enrichment steps can be avoided. Validation data, including recovery, repeatability, and reproducibility of the method, were elaborated using an enriched margarine as example. The margarine was subjected to a heating procedure in order to exemplarily monitor the formation of phytosterol oxidation products. Quantification was performed using on-line LC-GC-FID, identification of the analytes was based on on-line LC-GC-MS. The developed approach offers a new possibility for the reliable and fast analysis of phytosterol oxidation products in enriched foods. Copyright © 2015 Elsevier B.V. All rights reserved.

Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry.

Science.gov (United States)

Gochman, Nathan; And Others

1979-01-01

A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

Mixed-mode chromatography/isotope ratio mass spectrometry.

Science.gov (United States)

McCullagh, James S O

2010-03-15

Liquid chromatography coupled to molecular mass spectrometry (LC/MS) has been a standard technique since the early 1970s but liquid chromatography coupled to high-precision isotope ratio mass spectrometry (LC/IRMS) has only been available commercially since 2004. This development has, for the first time, enabled natural abundance and low enrichment delta(13)C measurements to be applied to individual analytes in aqueous mixtures creating new opportunities for IRMS applications, particularly for the isotopic study of biological molecules. A growing number of applications have been published in a range of areas including amino acid metabolism, carbohydrates studies, quantification of cellular and plasma metabolites, dietary tracer and nucleic acid studies. There is strong potential to extend these to new compounds and complex matrices but several challenges face the development of LC/IRMS methods. To achieve accurate isotopic measurements, HPLC separations must provide baseline-resolution between analyte peaks; however, the design of current liquid interfaces places severe restrictions on compatible flow rates and in particular mobile phase compositions. These create a significant challenge on which reports associated with LC/IRMS have not previously focused. Accordingly, this paper will address aspects of chromatography in the context of LC/IRMS, in particular focusing on mixed-mode separations and their benefits in light of these restrictions. It aims to provide an overview of mixed-mode stationary phases and of ways to improve high aqueous separations through manipulation of parameters such as column length, temperature and mobile phase pH. The results of several practical experiments are given using proteogenic amino acids and nucleosides both of which are of noted importance in the LC/IRMS literature. This communication aims to demonstrate that mixed-mode stationary phases provide a flexible approach given the constraints of LC/IRMS interface design and acts as a

Normalization of natural gas composition data measured by gas chromatography

International Nuclear Information System (INIS)

Milton, Martin J T; Harris, Peter M; Brown, Andrew S; Cowper, Chris J

2009-01-01

The composition of natural gas determined by gas chromatography is routinely used as the basis for calculating physico-chemical properties of the gas. Since the data measured by gas chromatography have particular statistical properties, the methods used to determine the composition can make use of a priori assumptions about the statistical model for the data. We discuss a generalized approach to determining the composition, and show that there are particular statistical models for the data for which the generalized approach reduces to the widely used method of post-normalization. We also show that the post-normalization approach provides reasonable estimates of the composition for cases where it cannot be shown to arise rigorously from the statistical structure of the data

Effects of salts on protein-surface interactions: applications for column chromatography.

Science.gov (United States)

Tsumoto, Kouhei; Ejima, Daisuke; Senczuk, Anna M; Kita, Yoshiko; Arakawa, Tsutomu

2007-07-01

Development of protein pharmaceuticals depends on the availability of high quality proteins. Various column chromatographies are used to purify proteins and characterize the purity and properties of the proteins. Most column chromatographies require salts, whether inorganic or organic, for binding, elution or simply better recovery and resolution. The salts modulate affinity of the proteins for particular columns and nonspecific protein-protein or protein-surface interactions, depending on the type and concentration of the salts, in both specific and nonspecific manners. Salts also affect the binding capacity of the column, which determines the size of the column to be used. Binding capacity, whether equilibrium or dynamic (under an approximation of a slow flow rate), depends on the binding constant, protein concentration and the number of the binding site on the column as well as nonspecific binding. This review attempts to summarize the mechanism of the salt effects on binding affinity and capacity for various column chromatographies and on nonspecific protein-protein or protein-surface interactions. Understanding such salt effects should also be useful in preventing nonspecific protein binding to various containers. Copyright 2007 Wiley-Liss, Inc.

Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses.

Science.gov (United States)

Muthukrishnan, Suriyavathana; Palanisamy, Subha; Subramanian, Senthilkumar; Selvaraj, Sumathi; Mari, Kavitha Rani; Kuppulingam, Ramalingam

2016-08-01

Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. The HPLC analysis of ELEV showed the presence of gallic and caffeic acids as the major components at concentrations of 2.0 ppm and 0.1 ppm, respectively, as well as other components. GC-MS analysis revealed the presence of 3-eicosyne; 3,7,11,15-tetramethyl-2-hexadecen-1-ol; butanoic acid, 3-methyl-3,7-dimethyl-6-octenyl ester; phytol; 1,2-benzenedicarboxylic acid, diundecyl ester; 1-octanol, 2-butyl-; squalene; and 2H-pyran, 2-(7-heptadecynyloxy) tetrahydro-derivative. Because pharmacopuncture is a new evolving natural mode that uses herbal extracts for treating patients with various ailments with minimum pain and maximum effect, the results of this study are particularly important and show that ELEV possesses a wide range of phytochemical constituents, as indicated above, as effective active principle molecules that can be used individually or in combination to treat patients with various diseases. Copyright © 2016. Published by Elsevier B.V.

Supercritical fluid chromatography hyphenated with twin comprehensive two-dimensional gas chromatography for ultimate analysis of middle distillates.

Science.gov (United States)

Adam, Frédérick; Thiébaut, Didier; Bertoncini, Fabrice; Courtiade, Marion; Hennion, Marie-Claire

2010-02-19

This paper reports the conditions of online hyphenation of supercritical fluid chromatography (SFC) with twin comprehensive two-dimensional gas chromatography (twin-GCxGC) for detailed characterization of middle distillates; this is essential for a better understanding of reactions involved in refining processes. In this configuration, saturated and unsaturated compounds that have been fractionated by SFC are transferred on two different GC x GC columns sets (twin-GCxGC) placed in the same GC oven. Cryogenic focusing is used for transfer of fractions into the first dimension columns before simultaneous GCxGC analysis of both saturated and unsaturated fractions. The benefits of SFC-twin-GC x GC are demonstrated for the extended alkane, iso-alkane, alkene, naphthenes and aromatics analysis (so-called PIONA analysis) of diesel samples which can be achieved in one single injection. For that purpose, saturated and unsaturated compounds have been separated by SFC using a silver loaded silica column prior to GC x GC analysis. Alkenes and naphthenes are quantitatively recovered in the unsaturated and saturated fractions, respectively, allowing their identification in various diesel samples. Thus, resolution between each class of compounds is significantly improved compared to a single GCxGC run, and for the first time, an extended PIONA analysis of diesel samples is presented. Copyright 2009 Elsevier B.V. All rights reserved.