Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-2168 Zeitschriftenartikel Falkenhagen, Jana; Friedrich, Jörg Florian; Schulz, Günter; Krüger, Ralph-Peter; Much, Helmut; Weidner, Steffen Liquid Adsorption Chromatography near Critical Conditions of Adsorption coupled with Matrix-assisted Laser Desorption/Ionization Mass Spectrometry Chemical heterogeneities and molecular weight distributions of poly(ethylene oxide) (PEO)-co-polymethylene (PM) model oligomers, which are relevant to the synthesis of commonly used tensides, were investigated. For analytical characterization, the well-known principle of liquid adsorption chromatography at 'critical conditions' (LACCC) was modified. Near the critical conditions of adsorption of the PEO unit, e.g., at slight adsorption conditions of PM, the copolymers could be separated according to their PM chain length. The eluates were separated and single fractions of each peak were continuously transferred onto the MALDI target by means of a commercially available device. Simultaneously, the MALDI matrix solution was continuously added with a second pump. This procedure offers the possibility of the formation of homogeneous matrix-polymer textures. By MALDI-MS a complete characterization of the chemical composition (PEO and PM chain length) of each peak could be achieved. The obtained MALDI mass spectra of the eluates at different retention times could be used for the molecular weight calibration of the LAC system. In this way, an additional application of SEC, as in conventional 2D-chromatography, was avoided by using the MALDI method as quasi chromatographic separation Amsterdam Gordon and Breach Publ. 2000 International journal of polymer analysis and characterization 5 549 562 10.1080/10236660008034644 2016-02-19 OPUS4-26026 Zeitschriftenartikel Zhao, J.; Schlaad, H.; Weidner, Steffen; Antonietti, M. Synthesis of terpene-poly(ethylene oxide)s by t-BuP4-promoted anionic ring-opening polymerization Terpene alcohols (menthol, retinol, cholesterol, and betulin) together with the phosphazene base t-BuP4 were used as initiating systems for anionic ring-opening polymerization of ethylene oxide. The polymerizations were conducted in a controlled manner with the initial molar ratio of t-BuP4 to hydroxyl groups of 0.01-0.2, yielding a series of biohybrid polymers comprising terpene entities and poly(ethylene oxide) (PEO) chains with low polydispersities and tunable compositions (57-87 wt% of PEO). Samples were characterized by NMR and UV/visible spectroscopy, MALDI-TOF mass spectrometry, and size exclusion chromatography; thermal properties were studied by differential scanning calorimetry. The concept of this study opens a new toolbox of terpene-based biohybrid polymers with variable properties and functions. Royal Society of Chemistry (RSC) 2012 Polymer chemistry 3 7 1763 1768 10.1039/c1py00388g 2016-02-19 OPUS4-26395 Beitrag zu einem Sammelband Falkenhagen, Jana; Weidner, Steffen Barner-Kowollik, C.; Gründling, T.; Falkenhagen, J.; Weidner, S. Hyphenated techniques Wiley-VCH Verlag GmbH & Co. KGaA 2012 Mass spectrometry in polymer chemistry 978-3-527-32924-3 209 235 2016-02-19 OPUS4-27986 Zeitschriftenartikel Weidner, Steffen; Schultze, R.-D.; Enthaler, B. Matrix-assisted laser desorption/ionization imaging mass spectrometry of pollen grains and their mixtures RATIONALE The fast and univocal identification of different species in mixtures of pollen grains is still a challenge. Apart from microscopic evaluation and Raman spectroscopy, no other techniques are available. METHODS Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry was applied to the analysis of extracts of single pollen grains and pollen mixtures. Pollen grains were fixed, treated and covered with matrix directly on the MALDI target. RESULTS Clearly resolved MALDI ion intensity images could be obtained enabling the identification of single pollen grains in a mixture. CONCLUSIONS Our results demonstrate the potential and the suitability of MALDI imaging mass spectrometry as an additional method for the identification of pollen mixtures. Chichester Wiley 2013 Rapid communications in mass spectrometry 27 8 896 903 10.1002/rcm.6523 2016-02-20 OPUS4-24538 Zeitschriftenartikel Weidner, Steffen; Knappe, Patrick; Panne, Ulrich MALDI-TOF imaging mass spectrometry of artifacts in 'dried droplet' polymer samples Matrix-assisted laser desorption/ionization-timeof-flight (MALDI-TOF) imaging of polystyrenes with various molecular masses was applied to study spatial molecular mass distribution of polymers in sample spots prepared by the 'dried droplet' method. When different solvents and target surfaces were examined, a segregation of single homologous polymers was observed depending upon the evaporation rate of the solvent. For the observed Patterns left by the evaporating droplet, a hypothesis is offered taking into account different hydrodynamic interactions and diffusion. The results illustrate that spot preparation using the conventionally 'dried droplet' method is prone to artifacts and should be avoided for reliable and reproducible MALDI mass spectrometry experiments with regards to the Determination of molecular masses and mass distributions. Berlin Springer 2011 Analytical and bioanalytical chemistry 401 1 127 134 10.1007/s00216-011-4773-1 2016-02-19 OPUS4-24974 Zeitschriftenartikel Weidner, Steffen; Falkenhagen, Jana LC-MALDI-TOF imaging MS: a new approach in combining chromatography and mass spectrometry of copolymers A new approach that utilizes MALDI-TOF imaging mass spectrometry as a new detector for polymer chromatography is presented. For the first time, the individual retention behavior of single structural units of polyethylene oxide (PEO)/polypropylene oxide (PPO) copolymers and changes of the copolymer composition could be monitored. Composition specific calibration curves could be easily obtained by displaying the copolymer ion intensity data. This approach provides completely new insights in the chromatographic principle of copolymer separation and could be used to easily modify and adapt conditions for separation. In combination with electrospray deposition, homogeneous sample/matrix traces of surprisingly high spatial resolution could be obtained. Washington, DC American Chemical Society 2011 Analytical chemistry 83 23 9153 9158 10.1021/ac202380n 2016-02-19 OPUS4-17723 Zeitschriftenartikel Weidner, Steffen; Falkenhagen, Jana; Maltsev, Sergey; Sauerland, V.; Rinken, M. A novel software tool for copolymer characterization by coupling of liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry The results of copolymer characterization by coupling of chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques and subsequent calculation of copolymer composition using a novel software tool MassChrom2D are presented. For high-resolution mass analysis copolymer samples were fractionated by means of liquid adsorption chromatography (LAC). These fractions were investigated off-line by MALDI-TOF MS. Various mono-n-butyl ethers of polyethylene oxide-polypropylene oxide copolymers (PEO-co-PPO) were investigated. As well as the copolymer composition presented in two-dimensional plots, the applied approach can give additional hints on specific structure-dependent separation conditions in chromatography. Chichester Wiley 2007 Rapid communications in mass spectrometry 21 16 2750 2758 10.1002/rcm.3146 2016-02-19 OPUS4-21623 Zeitschriftenartikel Weidner, Steffen; Trimpin, s. Mass Spectrometry of Synthetic Polymers Washington, DC American Chemical Society 2010 Analytical chemistry 82 12 4811 4829 10.1021/ac101080n 2016-02-19 OPUS4-26098 Buchkapitel Weidner, Steffen Matyjaszewski, K.; Möller, M. Mass spectrometry: MALDI (Matrix-Assisted Laser Desorption/Ionization) and ESI (Electrospray Ionization) In recent years mass spectrometric methods, in particular matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) time-of-flight (TOF) mass spectrometry (MS) have become indispensable tools for analyzing molecular masses and mass distributions of polymers. Moreover, these techniques offer the advantage of being able to determine simultaneously chemical functionality, and compositional and topological distributions of polymers. Especially in combination with liquid and/or gas phase separation methods, a comprehensive polymer characterization can be achieved and the difficulties of MS to analyze chemically heterogeneous polymers, copolymers, and samples with broad molecular mass distribution can be overcome. Amsterdam Elsevier 2012 Polymer Science: A comprehensive reference 2 978-0-444-53349-4 Chapter 2.05 93 109 10.1016/B978-0-444-53349-4.00023-6 2016-02-19 OPUS4-52278 Vortrag Weidner, Steffen MALDI-TOF MS in der Synthese hochmolekularer Polylaktid Homo- und Copolymere Die MALDI-TOF Massenspektrometrie stellt eine wichtige Methode zur simultanen Bestimmung von Molmassen, Molmassenverteilungen und Endgruppen von synthetischen Polymeren dar. In dem Vortrag wird gezeigt, welche zusätzlichen Informationen über die Art der Polymerisation, der Nebenreaktionen und der Topologie der gebildeten hochmolekularen Polylaktid-Homo- und Copolymere im Verlauf ihrer Synthese erhalten werden können. 2021 Bruker Anwendertreffen Online meeting 05.03.2021 2021-03-17