TY - JOUR A1 - Gähde, J. A1 - Friedrich, Jörg Florian A1 - Fischer, T. A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Falkenhagen, Jana T1 - Reactions of polymer analogous model substances with metals and oxides KW - Modellverbindung KW - Al202 KW - Chrom KW - Orientierung, molekular KW - Chemical interaction KW - Model compounds KW - Al2O3 and chromium KW - Molecular orientation KW - Formation of complexes KW - Plasma PY - 1996 SN - 0340-255x SN - 1437-8027 VL - 101 SP - 194 EP - 198 PB - Springer CY - Berlin AN - OPUS4-685 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Stauf, W. A1 - Müller, A. H. E. T1 - Characterization of block copolymers by liquid adsorption chromatography at critical conditions. 1. Diblock copolymers N2 - Liquid adsorption chromatography at critical conditions (LACCC) in normal and in reversed-phase modes provides independent information on the molar mass distributions of both blocks of poly(methyl methacrylate)-block-poly(tert-butyl methacrylate), even if no information about the precursor is available. In addition, the amount of unreacted precursor can be determined, even if its molar mass is comparable to that of the total block copolymer. The reversal of elution order by changing of stationary and mobile phases makes it possible to independently characterize each block in the SEC mode of the LACCC system. Thus, complete structural information is obtained even without using two-dimensional chromatographic techniques. PY - 2000 U6 - https://doi.org/10.1021/ma991903j SN - 0024-9297 SN - 1520-5835 VL - 33 IS - 10 SP - 3687 EP - 3693 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter A1 - Gloede, J. T1 - Charakterisierung von Calixarenen durch Kopplung von Flüssigchromatographie und MALDI-TOF-MS KW - Flüssigchromatographie KW - Kopplung LACCC KW - MALDI-TOF-MS KW - Calixarene KW - Novolake PY - 2001 SN - 0016-3538 VL - 45 IS - 4 SP - 380 EP - 384 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-2177 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Montag, P. A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana T1 - Strukturanalyse in komplexen Polymersystemen PY - 1999 SN - 0943-6677 VL - 50 IS - 7 SP - 253 EP - 257 PB - Rubikon CY - Gaiberg bei Heidelberg AN - OPUS4-2164 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Friedrich, Jörg Florian A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Much, Helmut T1 - Liquid Adsorption Chromatography near Critical Conditions of Adsorption coupled with Matrix-assisted Laser/Ionization Mass Spectrometry T2 - 47th ASMS Conference on Mass Spectrometry and Allied Topics CY - Dallas, TX, USA DA - 1999-06-13 PY - 1999 CY - Dallas, Tex AN - OPUS4-2165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Friedrich, Jörg Florian A1 - Schulz, Günter A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Weidner, Steffen T1 - Liquid Adsorption Chromatography near Critical Conditions of Adsorption coupled with Matrix-assisted Laser Desorption/Ionization Mass Spectrometry N2 - 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 KW - Liquid adsorption chromatography KW - Matrix-assisted laser desorption KW - Ionization mass spectrometry KW - Coupling methods KW - MALDI PY - 2000 U6 - https://doi.org/10.1080/10236660008034644 SN - 1023-666X SN - 1563-5341 VL - 5 SP - 549 EP - 562 PB - Gordon and Breach Publ. CY - Amsterdam AN - OPUS4-2168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Krüger, Ralph-Peter A1 - Friedrich, Jörg Florian T1 - Determination of chemical and molecular-weight distributions of heterogeneous polymers by means of MALDI-MS coupled with chromatography T2 - 219th ACS national meeting CY - San Francisco, CA, USA DA - 2000-03-26 PY - 2000 SN - 0032-3934 VL - 41 IS - 1 SP - 655 EP - 656 PB - American Chemical Society CY - Newark, NJ AN - OPUS4-2169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Spranger, K. T1 - Neue Möglichkeiten der Polymercharakterisierung durch 2D-HPLC, Kopplung mit spektroskopischen Methoden und MALDI-TOF-MS T2 - Gesellschaft Deutscher Chemiker, "Klassische Polymere im Aufwind, Polymerchemie aktuell" CY - Dresden, Deutschland DA - 1996-03-25 PY - 1996 CY - Dresden AN - OPUS4-2212 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Spranger, K. ED - Günther, W. T1 - MALDI-TOF-MS zur Charakterisierung von synthetischen Polymeren in Kopplung mit der HPLC T2 - InCom '96 - International Symposium on Instrumentalized Analytical Chemistry and Computer Technology CY - Düsseldorf, Deutschland DA - 1996-03-25 PY - 1996 PB - IAS CY - Moers AN - OPUS4-2213 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Spranger, K. T1 - Zur Charakterisierung von synthetischen Polymeren durch MALDI-TOF in Kopplung mit der LACCC T2 - Analytica Conference 96 CY - München, Deutschland DA - 1996-04-23 PY - 1996 PB - Messe München GmbH CY - München AN - OPUS4-2219 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gähde, J. A1 - Fischer, T. A1 - Falkenhagen, Jana A1 - Dittmar, A. A1 - Gnauck, R. T1 - Interaction of Polyurethane Model Compounds with Metal Oxides KW - Polyurethane model compounds KW - Mono layers KW - Specific interaction at oxide surfaces KW - Catalyzed hydrolysis PY - 1997 SN - 0021-8995 SN - 1097-4628 VL - 64 SP - 2449 EP - 2455 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-2156 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Jancke, Harald A1 - Krüger, Ralph-Peter A1 - Rikowski, Eckhard A1 - Schulz, Günter T1 - Characterization of Silsesquioxanes by Size-exclusion chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry N2 - Liquid chromatography in combination with spectroscopic methods like matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) or nuclear magnetic resonance (NMR) spectroscopy is a powerful method to characterize silsesquioxanes and silsesquioxane mixtures. As new examples, the formation of silsesquioxyl-substituted silsesquioxanes [(n-octyl)7(SiO1.5)8]2O and [(n-octyl)7(SiO1.5)8O]2[(n-octyl)6(SiO1.5)8] as well as the cage rearrangement of octa-[(n-heptyl)silsesquioxane] to larger structur es [(n-heptyl)SiO1.5)]n up to n=28 are shown. PY - 2003 U6 - https://doi.org/10.1002/rcm.911 SN - 0951-4198 SN - 1097-0231 VL - 17 IS - 4 SP - 285 EP - 290 PB - Wiley CY - Chichester AN - OPUS4-2182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Stauf, W. A1 - Müller, A. H. E. T1 - Characterization of di- and triblock copolymers using coupled chromatogreaphic methods PY - 1999 SN - 0032-3934 VL - 40 IS - 2 SP - 984 EP - 985 PB - American Chemical Society CY - Newark, NJ AN - OPUS4-2183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Dietrich, P. T1 - New aspects concerning the stability of silica-based HPLC separation phases PY - 1994 SN - 0010-2164 VL - 24 SP - 11 EP - 16 PB - International Scientific Communications CY - Greens Farms, Conn. AN - OPUS4-2184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter A1 - Weinmann, S. T1 - Beiträge zur Charakterisierung von Polyactiden durch Kopplung von HPLC-Trennmethoden mit der MALDI-TOF-MS T2 - Analytica Conference 2002 CY - München, Deutschland DA - 2002-04-23 PY - 2002 AN - OPUS4-2188 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter A1 - Weinmann, S. ED - Radusch, H.-J. ED - Fiedler, L. T1 - Beiträge zur Charakterisierung von Polyactiden durch Kopplung von HPLC-Trennmethoden mit der MALDI-Flugzeitmassenspektrometrie T2 - Internationale Fachtagung Polymerwerkstoffe ; P-2002 CY - Halle (Saale), Deutschland DA - 2002-09-25 PY - 2002 SN - 3-86010-656-2 PB - Martin-Luther-Univ. Halle-Wittenberg CY - Halle (Saale) AN - OPUS4-2189 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter A1 - Heinemann, M. A1 - Weinmann, S. A1 - Friedrich, Jörg Florian A1 - Fritz, H.-G. ED - Fritz, H.-G. ED - Eisenbach, C. D. T1 - Synthese von Polylactiden mittels reaktiver Extrusion und Produktcharakterisierung durch Kopplung von HPLC-Methoden mit der MALDI-TOF-MS T2 - 18. Stuttgarter Kunststoff-Kolloquium CY - Stuttgart, Deutschland DA - 2003-03-19 PY - 2003 SN - 3-00-010663-4 IS - CD-ROM PB - Univ., IKT, IAMC CY - Stuttgart AN - OPUS4-2190 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter T1 - Calixarene in Photoresisten (Kopplung von flüssigchromatographischen Methoden mit der MALDI-TOF-MS) T2 - Fachgruppenvollversammlung BAM CY - Berlin, Deutschland DA - 2002-01-29 PY - 2002 AN - OPUS4-2191 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Polylactidanalytik T2 - Fachgruppenvollversammlung BAM CY - Berlin, Germany DA - 2002-01-29 PY - 2002 AN - OPUS4-2192 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter ED - Jutzi, P. ED - Schubert, U. T1 - Characterization of Si-polymers by coupling of HPLC-separation methods with MALDI-TOF-MS T2 - Symposium on Silicon Chemistry CY - Werfenweng, Österreich DA - 2002-01-01 PY - 2003 SN - 3-527-30647-1 SP - 406 EP - 418 PB - Wiley-VCH CY - Weinheim AN - OPUS4-2194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Maier, Bärbel A1 - Much, Helmut A1 - Schulz, Günter T1 - Orthogonal two-dimensional chromatography of poly(ethylene oxid) adducts T2 - HPLC '96 CY - San Francisco, CA, USA DA - 1996-06-16 PY - 1996 CY - San Francisco AN - OPUS4-2221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Much, Helmut A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter ED - Berger, T. T1 - New methods for characterization of polymer heterogeneity by combination of HPLC with MALDI-TOF-MS T2 - 21st International Symposium on Chromatography CY - Stuttgart, Germany DA - 1996-09-15 PY - 1996 SN - 0009-5893 IS - 45 PB - Vieweg CY - Wiesbaden AN - OPUS4-2223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Charakterisierung von Polymeren durch Kombination von HPLC und MALDI-TOF-MS T2 - Statusseminar des ACA CY - Berlin, Germany DA - 1996-11-05 PY - 1996 AN - OPUS4-2228 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter ED - Günther, W. T1 - Neue Ergebnisse der MALDI-TOF-Massenspektrometrie von synthetischen Polymeren T2 - InCom '97 - International Symposium on Instrumentalized Analytical Chemistry and Computer Technology CY - Düsseldorf, Deutschland DA - 1997-03-17 PY - 1997 VL - 97 PB - IAS CY - Moers AN - OPUS4-2230 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter T1 - Charakterisierung von Si-Polymerarchitekturen durch Kopplung von flüssigchromatographischen Methoden mit der MALDI-TOF-Massenspektrometrie im DFG-Schwerpunktprogramm T2 - DFG-Kolloquium zum Schwerpunktprogramm "Silicium-Chemie" CY - Bielefeld, Deutschland DA - 1997-05-12 PY - 1997 AN - OPUS4-2231 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter ED - Fell, A. T1 - Two-dimensional chromatography, their optimization and coupling with different detection techniques for investigation of polymer heterogeneity T2 - 21st International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC) CY - Birmingham, England, UK DA - 1997-06-22 PY - 1997 SN - 0021-9673 PB - Elsevier CY - Amsterdam AN - OPUS4-2232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Coupling of different modes of liquid chromatography of polymers with spectroscopic methods and MALDI-TOF-MS-key for determination of polymer heterogeneity T2 - 6th SPSJ International Polymer Conference (IPC 97) CY - Kusatsu, Japan DA - 1997-10-20 PY - 1997 VL - 6 AN - OPUS4-2233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter T1 - Neue Ergebnisse der HPLC/MALDI-TOF-MS - Kopplung zur Charakterisierung von synthetischen Polymeren T2 - Analytica Conference 98 CY - München, Deutschland DA - 1998-04-21 PY - 1998 CY - München AN - OPUS4-2235 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Rikowski, E. T1 - Characterization of silicon polymers (silsesquioxanes, dendrimers and copolymers) by means of different modes of Liquid Chromatography and MALDI-TOF-MS PY - 1998 PB - Messe München GmbH CY - München AN - OPUS4-2236 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Rikowski, E. T1 - Zur Charakterisierung von Si-Polymeren durch MALDI-TOF-MS in Kopplung mit flüssigchromatographischen Arbeitsweisen T2 - InCom '99 CY - Düsseldorf, Deutschland DA - 1999-03-22 PY - 1999 AN - OPUS4-2238 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Friedrich, Jörg Florian A1 - Much, Helmut A1 - Schulz, Günter A1 - Falkenhagen, Jana T1 - Zur Charakterisierung von Si-Polymeren durch Kopplung flüssigchromatographischer Arbeitsweisen mit der MALDI-TOF-MS T2 - DFG-Symposium zum Schwerpunktprogramm "Silicium-Chemie" CY - Bielefeld, Deutschland DA - 1999-05-09 PY - 1999 AN - OPUS4-2239 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Investigations of Polymer Heterogeneity by Two-Dimensional HPLC, MALDI-TOF-MS and FTIR Coupling T2 - ISPAC 8, HPLC ´95 CY - Sanibel Island, FL, USA DA - 1995-05-20 PY - 1995 PB - Gordon and Breach CY - Sant Helier AN - OPUS4-2203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Characterization and identification of new polymer structures by optimization and coupling of HPLC and MALDI-TOF-MS T2 - Polymerwerkstoffe 2000 CY - Halle (Saale), Germany DA - 2000-09-25 PY - 2000 AN - OPUS4-3365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Characterization and identification of new polymer structures by optimization and coupling of HPLC and MALDI-TOF-MS T2 - Diskussionstagung der DECHEMA, Neue Methoden der Polymeranalytik CY - Mainz, Germany DA - 2001-04-02 PY - 2001 AN - OPUS4-3366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Investigation of heterogeneity of polyethers by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - ISPAC 2000 CY - Pittsburgh, PA, USA DA - 2000-06-19 PY - 2000 AN - OPUS4-3765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Investigation of heterogeneity of polyethers by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - Berliner Polymerentage 2000 CY - Berlin, Germany DA - 2000-10-09 PY - 2000 AN - OPUS4-3766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Günter A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter T1 - Kopplung von HPLC-Trennmethoden mit der MALDI-TOF-Massenspektrometrie zur Charakterisierung von Si-haltigen Verbindungen T2 - DFG-Symposium zum Schwerpunktprogramm "Silicium-Chemie" CY - Werfenweng, Österreich DA - 2002-05-02 PY - 2002 AN - OPUS4-1797 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Charakterisierung von synthetischen Polymeren mit komplexen Strukturen durch HPLC / MALDI-MS-Kopplung T2 - Makromolekulares Kolloquium, DKI CY - Darmstadt, Germany DA - 2002-07-05 PY - 2002 AN - OPUS4-1799 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter T1 - Einführung in die MALDI-TOF-Massenspektrometrie an synthetischen Polymeren T2 - Innovent Technologieentwicklung CY - Jena, Deutschland DA - 2002-08-14 PY - 2002 AN - OPUS4-1800 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Polymercharakterisierung mittels flüssigchromatographischer und spektroskopischer Methoden T2 - Innovent Technologieentwicklung CY - Jena, Deutschland DA - 2002-08-14 PY - 2002 AN - OPUS4-1801 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Mehrdimensionale Analysenverfahren für komplexe Polymere - Arbeitskreis Polymeranalytik T2 - Tagung des Arbeitskreises Polymeranalytik CY - Darmstadt, Deutschland DA - 2002-09-25 PY - 2002 AN - OPUS4-1802 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Charakterisierung von Polymeren durch Kopplung von flüssigchromatographischen und spektroskopischen Methoden T2 - HPLC-Tage CY - Mannheim, Deutschland DA - 2002-11-12 PY - 2002 AN - OPUS4-1803 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Polymercharakterisierung durch Kombination chromatographischer Verfahren sowie HPLC - MALDI-TOF-MS - Kopplung T2 - Tagung der BASF AG 2002 CY - Ludwigshafen, Deutschland DA - 2002-12-03 PY - 2002 AN - OPUS4-1804 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Polymer Characterization by LC / MALDI-MS Coupling T2 - Vortragstagung "Funktionspolymere für Systemlösungen" CY - Darmstadt, Germany DA - 2002-03-18 PY - 2002 AN - OPUS4-1805 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Characterization of polylactides by coupling of chromatographic methods with MALDI-TOF-MS T2 - Polydays 2002 ; ISPAC 2002 CY - Berlin, Germany DA - 2002-09-30 PY - 2002 AN - OPUS4-1807 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Friedrich, Jörg Florian T1 - Beiträge zur Charakterisierung von synthetischen Si-Polymeren durch Kopplung von HPLC-Trennmethoden mit der MALDI-TOF-MS T2 - DFG-Symposium zum Schwerpunktprogramm "Silicium-Chemie" CY - Werfenweng, Österreich DA - 2000-09-27 PY - 2000 AN - OPUS4-2251 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Gerstung, Vanessa A1 - Much, Helmut A1 - Schulz, Günter A1 - Friedrich, Jörg Florian T1 - Beiträge zur Charakterisierung von synthetischen Si-Polymeren durch Kopplung von HPLC-Trennmethoden mit der MALDI-TOF-Massenspektrometrie T2 - Berliner Polymeren-Tage 2000 CY - Berlin, Deutschland DA - 2000-10-09 PY - 2000 CY - Berlin AN - OPUS4-2252 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Friedrich, Jörg Florian T1 - Beiträge zur Charakterisierung von synthetischen Si-Polymeren durch Kopplung von HPLC-Trennmethoden mit der MALDI-TOF-MS T2 - Incom 2001 - International Symposium on Instrumentalized Analytical Chemistry and Computer Technology CY - Düsseldorf, Deutschland DA - 2001-03-27 PY - 2001 AN - OPUS4-2254 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Characterization and identification of new polymer structures by optimization and coupling of HPLC and MALDI-TOF-MS T2 - Dechema-Diskussionstagung "Neue Methoden der Polymeranalytik" CY - Mainz, Germany DA - 2001-04-02 PY - 2001 CY - Mainz AN - OPUS4-2255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Polymer characterization by LC / MALDI-MS coupling T2 - Bayreuther Polymer Symposium 2001 CY - Bayreuth, Germany DA - 2001-09-16 PY - 2001 CY - Bayreuth AN - OPUS4-2256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Charakterisierung von synthetischen Polymeren durch Kopplung flüssigchromato-graphischer Trennmethoden mit der MALDI-TOF-Massenspektrometrie T2 - 1. Berliner Werkstofftag CY - Berlin, Deutschland DA - 1999-09-16 PY - 1999 AN - OPUS4-2242 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Much, Helmut A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Charakterisierung von synthetischen Polymeren durch Kopplung flüssigchromato-graphischer Trennmethoden mit der MALDI-TOF-Massenspektrometrie T2 - Workshop "Hierarchic Structure Formation and Function of Organic-Inorganic Hybrid Systems" CY - Ulm, Deutschland DA - 1999-11-26 PY - 1999 AN - OPUS4-2243 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schulz, Günter A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Rikowski, E. ED - Cherdron, H. T1 - Nachweis neuer Si-Polymerstrukturen durch die Kopplung der SEC mit der MALDI-TOF-MS T2 - Symposium on Tailormade Polymers CY - Merseburg, Deutschland DA - 2000-03-20 PY - 2000 SN - 3-527-30325-1 SN - 1022-1360 N1 - Serientitel: Macromolecular symposia – Series title: Macromolecular symposia IS - 163 PB - Wiley-VCH CY - Weinheim AN - OPUS4-2244 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter T1 - Beiträge zur Charakterisierung von synthetischen Si-Polymeren durch Kopplung von HPLC-Trennmethoden mit der MALDI-TOF-MS T2 - Analytica Conference 2000 CY - München, Deutschland DA - 2000-04-11 PY - 2000 CY - München AN - OPUS4-2245 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Just, Ulrich ED - Yeung, E. T1 - Characterization of silicon polymers by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - 24th International Symposium on High Performance Liquid Phase Separations and Related Techniques ; 24th HPLC 2000 CY - Seattle, WA, USA DA - 2000-06-24 PY - 2000 SN - 0021-9673 PB - Elsevier CY - Amsterdam AN - OPUS4-2247 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Investigation of heterogeneity of polyethers by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - HPLC 2000 - 2nd Prize bei HPLC-2000 CY - Seattle, WA, USA DA - 2000-06-24 PY - 2000 AN - OPUS4-2248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen ED - Grellmann, W. T1 - Characterization and identification of new polymer structures by optimization and coupling of HPLC and MALDI-TOF-MS T2 - Polymerwerkstoffe 2000 CY - Halle (Saale), Germany DA - 2000-09-25 PY - 2000 SN - 3-86010-605-8 PB - Martin-Luther-Univ. CY - Halle AN - OPUS4-2250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Coupling of different modes of liquid chromatography of polymers with spectroscopic methods and MALDI-TOF-MS-key for determination of polymer heterogeneity T2 - 6th SPSJ International Polymer Conference (IPC 97) CY - Kusatsu, Japan DA - 1997-10-20 PY - 1997 AN - OPUS4-3451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Characterization of polylactides by coupling of chromatographic methods with MALDI-TOF-MS T2 - ISPAC CY - Enschede, Netherlands DA - 2002-06-17 PY - 2002 AN - OPUS4-3454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Characterization of polylactides by coupling of chromatographic methods with MALDI-TOF-MS T2 - Polydays 2002, TU Berlin CY - Berlin, Germany DA - 2002-09-30 PY - 2002 AN - OPUS4-3455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Just, Ulrich T1 - Characterization of silicon polymers by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - HPLC 2000 CY - Seattle, WA, USA DA - 2000-06-24 PY - 2000 AN - OPUS4-3458 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kukula, H. A1 - Schlaad, H. A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana T1 - Improved Synthesis and Characterization of w-Primary Amino-Functional Polystyrenes and Polydienes PY - 2002 U6 - https://doi.org/10.1021/ma0204397 SN - 0024-9297 SN - 1520-5835 VL - 35 IS - 18 SP - 7157 EP - 7160 PB - American Chemical Society CY - Washington, DC AN - OPUS4-1659 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter A1 - Heinemann, M. T1 - Methodenkopplung zur Polylactidcharakterisierung PY - 2003 SN - 0344-1733 SN - 1610-8256 VL - 27 SP - 56 EP - 57 PB - Vogel CY - Würzburg AN - OPUS4-2597 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Investigations of Polymer Heterogeneity by Two-Dimensional HPLC, MALDI-TOF-MS and FTIR Coupling T2 - ISPAC 8, HPLC ´95 CY - Sanibel Island, FL, USA DA - 1995-05-20 PY - 1995 AN - OPUS4-3136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Advances in characterization of polymer heterogeneity by coupling of chromatographic and spectroscopic methods T2 - International Discussion Meeting, Deutsche Bunsen-Gesellschaft für Physikalische Chemie CY - Mainz, Germany DA - 1999-03-15 PY - 1999 AN - OPUS4-3282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Heinemann, M. A1 - Weinmann, S. T1 - Synthesis of Polylactides and thier characterization by coupling of liquid chromatographic mathods with MALDI-TOF-MS T2 - 7th International Symposium on Polymers for Advanced Technologies CY - Fort Lauderdale, FL, USA DA - 2003-09-21 PY - 2003 AN - OPUS4-3542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Charakterisierung von Polymeren durch Kopplung von flüssigchromatographischen und spektroskopischen Methoden T2 - HPLC-Tage CY - Mannheim, Germany DA - 2002-11-12 PY - 2002 AN - OPUS4-3549 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Rikowski, E. A1 - Schulz, Günter A1 - Friedrich, Jörg F. T1 - Synthesis and Characterization of Polyhedral Silsesquioxanes with Nanotubular Structures T2 - DFG-Schwerpunktprogramm "Nanodrähte und Nanoröhren" CY - Bad Honnef, Germany DA - 2004-01-23 PY - 2004 AN - OPUS4-4338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Schulz, Günter A1 - Heinemann, M. T1 - Characterization of Polyesters and Copolyesters by Coupled Liquid Chromatographic and Spectroscopic Techniques T2 - Polydays 2004 CY - Potsdam, Germany DA - 2004-10-04 PY - 2004 AN - OPUS4-4341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen A1 - Schulz, Günter T1 - Characterization of Polyesters and Copolyesters By Coupled Liquid Chromatographic and Spectroscopic Techniques T2 - Separation and Characterization of Natural and Synthetic Macromolecules (SCM-2) CY - Amsterdam, Netherlands DA - 2005-02-02 PY - 2005 AN - OPUS4-4342 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen T1 - Coupled Separation and Detection Techniques: New Aspects and Problems T2 - 17th International Symposium on Polymer Analysis and Characterization (ISPAC 2004) CY - Heidelberg, Germany DA - 2004-06-06 PY - 2004 AN - OPUS4-4343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Application of Solvent-free Sample Preparation for LC/MALDI-MS Coupling T2 - 52nd ASMS Conference CY - Nashville, TN, USA DA - 2004-05-23 PY - 2004 AN - OPUS4-4344 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Lösemittelfreie Probenpräparation in der Chromatographie - MALDI Kopplung T2 - 8. Kolloquium "MALDI-TOF-MS und synthetische Polymere", BAM CY - Berlin, Germany DA - 2004-05-11 PY - 2004 AN - OPUS4-4345 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Rikowski, E. A1 - Friedrich, Jörg F. T1 - Synthesis and Characterization of Polyhedral Silsesquioxanes with Nanotubular Structures T2 - DFG-Schwerpunktprogramm "Nanodrähte und Nanoröhren" CY - Bad Honnef, Germany DA - 2004-04-23 PY - 2004 AN - OPUS4-5095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Möglichkeiten zur Polymercharakterisierung durch die Anwendung verschiedener HPLC-Modi in Kopplung mit der MALDI-TOF-MS T2 - WGE Polymertreffen 1999 CY - Potsdam, Germany DA - 1999-05-06 PY - 1999 AN - OPUS4-11129 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Characterization of silicon polymers by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - ISPAC 2000 CY - Pittsburgh, PA, USA DA - 2000-06-18 PY - 2000 AN - OPUS4-11130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Investigations of Polymer Structures Using Chromatographic and Spectroscopic Techniques T2 - Esparation and Characterization of Macromolecules CY - Bratislava, Slovakia DA - 1999-07-04 PY - 1999 AN - OPUS4-11131 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - New Aspects of Characterization of Polymer Structures by Coupling of Different HPLC Modes with MALDI-TOF-MS T2 - Workshop on Mass Spectrometry of Polymers CY - Catania, Italy DA - 1999-12-01 PY - 1999 AN - OPUS4-11132 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Charakterisierung strukturheterogener Polymersysteme T2 - BAM-Kolloquium CY - Berlin, Germany DA - 2000-09-07 PY - 2000 AN - OPUS4-11133 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Neue Wege zur analytischen Charakterisierung komplexer Polymersysteme T2 - BAM-Kuratoriumssitzung CY - Berlin, Germany DA - 2000-05-16 PY - 2000 AN - OPUS4-11135 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Rikowski, Eckhard A1 - Schulz, Günter A1 - Friedrich, Jörg Florian ED - Grellmann, W. T1 - Synthesis and Characterisation of Polyhedral Silsesquioxanes with Nanotubular Structures T2 - 23. DVM-Vortrags- und Diskussionstagung "Werkstoffprüfung 2005", DA - 2005-12-01 PY - 2005 SP - 25 EP - 30 PB - DVM AN - OPUS4-11947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Krüger, Ralph-Peter A1 - Just, Ulrich A1 - Thünemann, Andreas T1 - Polymer characterization by hyphenated chromatographic techniques coupled with MALDI and ESI mass spectrometry T2 - Australasian Polymer Symposium (29th APS) CY - Hobart, Australia DA - 2007-02-11 PY - 2007 AN - OPUS4-13820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Just, Ulrich T1 - Characterization of Polymer Heterogeneity by Hyphenated Techniques (Coupling of HPLC and MALDI-TOF-MS) T2 - Polymer Laboratories CY - Church Stretton, England DA - 1996-06-28 PY - 1996 AN - OPUS4-11185 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen A1 - Schulz, Günter T1 - Kombinierte Trenn- und Detektionstechniken: Neue Aspekte und Probleme T2 - Seminar der Abteilung VI "Funktion von Polymeren", BAM CY - Berlin, Germany DA - 2004-06-03 PY - 2004 AN - OPUS4-5531 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen A1 - Schulz, Günter T1 - Characterization of polyesters and copolyesters by coupled chromatographic and spectroscopic techniques T2 - 2nd International Symposium on the Separation and Characterization of Natural and Synthetic Macromolecules SCM-2 CY - Amsterdam, Netherlands DA - 2005-02-02 PY - 2005 AN - OPUS4-5535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Rittig, F. T1 - Characterisierung von Polyvinylpyrollidonen T2 - Fachgruppenvollversammlung VI.3, BAM CY - Berlin, Germany DA - 2004-12-14 PY - 2004 AN - OPUS4-5537 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen T1 - Coupled Separation and Detection Techniques: New Aspects and Problems T2 - 17th International Symposium on Polymer Analysis and Characterization (ISPAC 2004) CY - Heidelberg, Germany DA - 2004-06-07 PY - 2004 AN - OPUS4-5530 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Detection limits of matrix-assisted laser desorption/ionisation mass spectrometry coupled to chromatography - a new application of solvent-free sample preparation N2 - The detection limits of matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) by semi-online coupling with chromatography were investigated using various mixtures of polyethylene oxides (PEOs) with different end groups. In contrast to the common dried-droplet sample preparation technique, which results in an inhomogeneous sample-to-matrix ratio within the MALDI spot, the used coupling technique offers a very high reproducibility combined with surpassing sensitivity of a few femtograms over a broad range of sample-to-matrix ratios. These results are in correlation with the results of the recently established solvent-free MALDI-TOFMS method utilising the grinding approach and are also of assistance towards the more theoretical aspect of MALDI that suggests that there is no necessity for an analyte incorporation into a matrix crystal for excellent matrix-assistance. PY - 2005 U6 - https://doi.org/10.1002/rcm.2256 SN - 0951-4198 SN - 1097-0231 VL - 19 IS - 24 SP - 3724 EP - 3730 PB - Wiley CY - Chichester AN - OPUS4-11859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Anwendung der LC-MS in der Polymeranalytik T2 - Analytica 2012 CY - Munich, Germany DA - 2012-04-17 PY - 2012 AN - OPUS4-25762 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Falkenhagen, Jana A1 - Weidner, Steffen ED - Barner-Kowollik, C. ED - Gründling, T. ED - Falkenhagen, J. ED - Weidner, S. T1 - Hyphenated techniques KW - MALDI KW - Chromatography KW - Coupling techniques PY - 2012 SN - 978-3-527-32924-3 SP - 209 EP - 235 PB - Wiley-VCH Verlag GmbH & Co. KGaA AN - OPUS4-26395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Radke, W. A1 - Falkenhagen, Jana ED - Haddad, P.R. ED - Poole, C.F. ED - Fanali, S. ED - Schoenmakers, P. ED - Lloyd, D. T1 - Liquid interaction chromatography of polymers N2 - In the last decade, the use of interaction chromatography and hyphenated techniques has become increasingly important for the characterization of polymeric materials. Interaction chromatography allows separation by other structural features than molar mass, while hyphenation with mass spectroscopy or spectroscopic techniques provides detailed characterization of the separated chromatographic fractions. This chapter gives an overview of the principles and applications of interaction chromatography and the information that can be determined by hyphenation of polymer chromatography with mass spectrometry and spectroscopic techniques. KW - Polymer chromatography KW - Gradient chromatography KW - Critical chromatography KW - SEC-gradients KW - 2D-chromatography KW - Hyphenation KW - MALDI KW - ESI KW - LC-FTIR KW - LC-NMR PY - 2013 SN - 978-0-12-415806-1 U6 - https://doi.org/10.1016/B978-0-12-415806-1.00005-X IS - Chapter 5 SP - 1 EP - 46 PB - Elsevier AN - OPUS4-27909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niehoff, A. A1 - Mantion, Alexandre A1 - McAloney, R. A1 - Huber, Alexandra A1 - Falkenhagen, Jana A1 - Goh, C.M. A1 - Thünemann, Andreas A1 - Winnik, M. A. A1 - Menzel, H. T1 - Elucidation of the structure of poly(gamma-benzyl-L-glutamate) nanofibers and gel networks in a helicogenic solvent N2 - The synthesis, characterization, self-assembly, and gel formation of poly(γ-benzyl-L-glutamate) (PBLG) in a molecular weight range from ca. 7,000–100,000 g/mol and with narrow molecular weight distribution are described. The PBLG is synthesized by the nickel-mediated ring-opening polymerization and is characterized by size-exclusion chromatography coupled with multiple-angle laser light scattering, NMR, and Fourier transform infrared spectroscopy. The self-assembly and thermoreversible gel formation in the helicogenic solvent toluene is investigated by transmission electron microscopy, atomic force microscopy, small-angle X-ray scattering, and synchrotron powder X-ray diffraction. At concentrations significantly below the minimum gelation concentration, spherical aggregates are observed. At higher concentrations, gels are formed, which show a 3D network structure composed of nanofibers. The proposed self-assembly mechanism is based on a distorted hexagonal packing of PBLG helices parallel to the axis of the nanofiber. The gel network forms due to branching and rejoining of bundles of PBLG nanofibers. The network exhibits uniform domains with a length of 200±42 nm composed of densely packed PBLG helices. KW - Poly(gamma-benzyl-L-glutamate) (PBLG) KW - Nickel-mediated NCA polymerization KW - Thermoreversible gel formation KW - Physical/supramolecular organogel KW - Nanofiber KW - Self-assembly KW - Alpha-helix KW - Nanotechnology KW - Small-angle X-ray scatering KW - SAXS PY - 2013 U6 - https://doi.org/10.1007/s00396-012-2866-9 SN - 0303-402X SN - 1435-1536 VL - 291 IS - 6 SP - 1353 EP - 1363 PB - Springer CY - Berlin AN - OPUS4-28615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Hoskins, Jessica T1 - Coupling techniques for copolymer characterization with focus on LC-MC T2 - ISPAC, 26th Int. Symposium on Polymer Analysis and Characterization CY - New Orleans, LA, USA DA - 2013-06-09 PY - 2013 AN - OPUS4-28631 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - LC-MALDI-TOF imaging MS: a new approach in combining chromatography and mass spectrometry of copolymers N2 - 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. KW - MALDI KW - Massenspektrometrie KW - Imaging KW - Chromatographie KW - Polymere PY - 2011 U6 - https://doi.org/10.1021/ac202380n SN - 0003-2700 SN - 1520-6882 VL - 83 IS - 23 SP - 9153 EP - 9158 PB - American Chemical Society CY - Washington, DC AN - OPUS4-24974 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - SURVEY OF COUPLING TECHNIQUES FOR POLYMER CHARACTERIZATION WITH FOCUS ON LC-MS T2 - SCM-6, Separation and Characterization of Macromolecules CY - Dresden, Germany DA - 2013-02-04 PY - 2013 AN - OPUS4-27658 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Rittig, F. A1 - Schrepp, W. A1 - Fandrich, N. A1 - Urtel, M. A1 - Weberndörfer, B. A1 - Just, Ulrich A1 - Weidner, Steffen A1 - Wittke, Wolfgang T1 - Characterization of Polyacetals by comprehensive 2D liquid chromatography an hyphenated techniques T2 - Separation and Characterization of Natural and Synthectic Macromolecules (SCM-2) CY - Amsterdam, Netherlands DA - 2005-02-02 PY - 2005 AN - OPUS4-11552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Rittig, F. T1 - Charakterisierung von Polyvinylpyrrolidon Homo- und Copolymeren T2 - 9. Kolloquium "MALDI-TOF-MS und synthetische Polymere", BAM CY - Berlin, Germany DA - 2005-05-10 PY - 2005 AN - OPUS4-11557 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Krüger, Ralph-Peter A1 - Just, Ulrich T1 - Characterization of copolyesters by coupling of liquid chromatography with MALDI and ESI mass spectrometry T2 - National Institute of Standards & Technology Polymer Mass Spectrometry Workshop CY - Gaithersburg, MD, USA DA - 2005-11-09 PY - 2005 AN - OPUS4-11544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trimpin, S. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - McEwen, C.N. T1 - Fractionation and Solvent-Free MALDI-MS Analysis of Polymers Using Liquid Adsorption Chromatography at Critical Conditions in Combination with a Multisample On-Target Homogenization/Transfer Sample Preparation Method N2 - A solvent-free homogenization/transfer matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) method is described for the preparation and precise transfer of up to 100 samples simultaneously on a single MALDI plate. This method is demonstrated using a poly(ethylene oxide) (PEO) mixture consisting of different molecular weights (500-6000) and end groups (PEO, dimethoxy-PEO, monomethoxy monomethacrylate-PEO, and dimethacrylate-PEO) that was fractionated using liquid adsorption chromatography at critical conditions. Off-line fractionation is performed prior to the on-target homogenization/transfer solvent-free sample preparation and MALDI mass analysis. The miniaturization of the solvent-free MALDI approach allowed analysis of less than 2 g per PEO component per fraction corresponding to ~200 pmol for PEO 6000. The amounts of polymer sample used for LC separation and the quality of the MS results are equivalent to the "dry spray" method; however, three times more fractions were collected and analyzed with the newly developed hyphenated approach. The off-line method eliminates optimization of, for example, spray conditions or spreading of organic solvents on the MALDI plate that occurs with droplet deposition methods. The widespread applications of MALDI make this solvent-free, multisample method particularly important as it expands the capabilities for obtaining mass measurements with great efficiencies in areas with increased sample numbers. In addition, the solvent-free method is well suited for automated MALDI analysis as it virtually eliminates the "dead-spot" phenomenon. PY - 2007 U6 - https://doi.org/10.1021/ac070986w SN - 0003-2700 SN - 1520-6882 VL - 79 IS - 19 SP - 7565 EP - 7570 PB - American Chemical Society CY - Washington, DC AN - OPUS4-17737 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Maltsev, Sergey A1 - Sauerland, V. A1 - Rinken, M. T1 - A novel software tool for copolymer characterization by coupling of liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry N2 - 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. KW - Copolymeranalytik KW - MALDI KW - Software KW - MS/MS KW - Kopplungsmethoden PY - 2007 U6 - https://doi.org/10.1002/rcm.3146 SN - 0951-4198 SN - 1097-0231 VL - 21 IS - 16 SP - 2750 EP - 2758 PB - Wiley CY - Chichester AN - OPUS4-17723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Weidner, Steffen A1 - Krüger, Ralph-Peter A1 - Panne, Ulrich A1 - Thünemann, Andreas T1 - LC / MALDI- and LC / ESI-TOF MS coupling for characterization of synthetic polymers T2 - ANAKON 2007 CY - Jena, Germany DA - 2007-03-27 PY - 2007 AN - OPUS4-14660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Just, Ulrich A1 - Thünemann, Andreas T1 - A new two-dimensional approach for copolymer characterization by LC / MALDI- and LC / ESI-TOF-MS T2 - European Polymer Congress 2007 CY - Portorož, Slovenia DA - 2007-07-02 PY - 2007 AN - OPUS4-14702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Just, Ulrich A1 - Thünemann, Andreas T1 - LC / MALDI- und LC / ESI-TOF-MS Kopplung zur Charakterisierung von Polyethern und Polyestern T2 - 11. MALDI-TOF-MS Kolloquium, BAM CY - Berlin, Germany DA - 2007-05-15 PY - 2007 AN - OPUS4-14705 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Just, Ulrich A1 - Thünemann, Andreas T1 - Charakterisierung strukturheterogener synthetischer Polymere mittels LC / MALDI- und LC / ESI-TOF-MS Kopplung T2 - MC-Kolloquium der Heinrich-Heine-Universität CY - Düsseldorf, Germany DA - 2007-05-03 PY - 2007 AN - OPUS4-14667 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mix, Renate A1 - Gerstung, Vanessa A1 - Falkenhagen, Jana A1 - Schulze, Rolf-Dieter A1 - Friedrich, Jörg Florian T1 - Characterization of plasma-polymerized allyl alcohol polymers and copolymers with styrene KW - Plasma polymerization KW - Surface functionalization KW - Molar mass PY - 2007 SN - 0169-4243 SN - 1568-5616 VL - 21 IS - 5-6 SP - 487 EP - 508 PB - VNU Science Press CY - Utrecht AN - OPUS4-14765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - UPLC/ESI-MS and HPLC/MALDI-MS-Complementary devices for copolymer characterization T2 - 20th International Symposium on Polymer Analysis and Characterization CY - Crete, Greece DA - 2007-10-01 PY - 2007 AN - OPUS4-15465 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Just, Ulrich T1 - Principle of Two-Dimensional Characterization of Copolymers N2 - Two-dimensional polymer characterization is used for a simultaneous analysis of molar masses and chemical heterogeneities (e.g., end groups, copolymer composition, etc.). This principle is based on coupling of two different chromatographic modes. Liquid adsorption chromatography at critical conditions (LACCC) is applied for a separation according to the chemical heterogeneity, whereas in the second-dimension fractions are analyzed with regard to their molar mass distribution by means of size exclusion chromatography (SEC). Because appropriate standards for a calibration of the SEC are seldom available, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) was used to substitute the SEC. The LACCC-MALDI MS coupling enables acquiring additional structural information on copolymer composition, which can considerably enhance the performance of this coupled method. KW - MALDI-TOF MS KW - Chromatographie KW - Kopplung PY - 2007 U6 - https://doi.org/10.1021/ac062145f SN - 0003-2700 SN - 1520-6882 VL - 79 IS - 13 SP - 4814 EP - 4819 PB - American Chemical Society CY - Washington, DC AN - OPUS4-17722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - New approach for copolymer characterization using multidimensional coupling methods T2 - 10th Annual UNESCO / IUPAC Conference on Macromolecules & Materials CY - Mpumalanga, South Africa DA - 2008-09-07 PY - 2008 AN - OPUS4-17887 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Synthesis and characterization of Polylactides by coupling of liquid chromatographic methods with MALDI-TOF-MS T2 - Kick-Off-Meeting; Bioabbaubare Verpackungen aus Polylactid CY - Darmstadt, Germany DA - 2008-05-08 PY - 2008 AN - OPUS4-17895 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Online UP-LACCC / ESI-TOF-MS for characterization of synthetic polymers as complementary tool to LC / MALDI-TOF-MS coupling T2 - 32nd International Symposium on HPLC and Related Techniques CY - Baltimore, MD, USA DA - 2008-05-10 PY - 2008 AN - OPUS4-17897 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Rapid determination of critical conditions of adsorption of synthetic coplymers by UPLC/ESI-MS T2 - Analytica Conference 2008 CY - Munich, Germany DA - 2008-04-01 PY - 2008 AN - OPUS4-17850 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Ralph-Peter A1 - Heinemann, M. A1 - Falkenhagen, Jana A1 - Hartmann, A. A1 - Friedrich, Jörg Florian A1 - Fritz, H.-G. ED - Fritz, H. ED - Eisenbach, C. T1 - Charakterisierung biologisch abbaubarer Homo- und Copolyester / Characterisation of biodegradable Homo- and Copolyesters T2 - 19. Stuttgarter Kunststoff-Kolloquium 2005 CY - Stuttgart, Deutschland DA - 2005-03-09 KW - MALDI-TOF-MS KW - Bioabbaubare Polyester KW - Flüssigchromatographie KW - Methodenkopplung KW - Biodegradable polyesters KW - Liquid chromatography KW - Coupling of analytical methods PY - 2005 SN - 3-00-015246-6 SP - 5/P1-1 - 5/P1-9 PB - IKT CY - Stuttgart AN - OPUS4-11767 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Krüger, Ralph-Peter A1 - Just, Ulrich T1 - Polymer characterization by combination of chromatographic techniques coupled with MALDI and ESI mass spectrometry T2 - Analytica Conference 2006 CY - Munich, Germany DA - 2006-04-25 PY - 2006 AN - OPUS4-12384 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Coupling of liquid-chromatographic, spectroscopic and spectrometric techniques for polymer characterization T2 - Polydays CY - Berlin, Germany DA - 2006-10-04 PY - 2006 AN - OPUS4-12377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Hyphenated liquid-chromatographic, spectroscopic and spectrometric techniques for polymer characterization T2 - Fraunhofer & PTS-Seminar CY - Potsdam, Germany DA - 2006-03-22 PY - 2006 AN - OPUS4-12378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Developments in Copolymer Characterization by chromatographic and spectroscopic techniques T2 - Pregl Colloquium at the National Institute of Chemistry, Slovenia CY - Ljubljana, Slovenia DA - 2013-10-16 PY - 2013 AN - OPUS4-29328 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - LC - MALDI/ESI-TOF-MS for Charactarization of Complex Polymer Systems T2 - 4th International Symposium on Separation and Characterization of Natural and Synthetic Macromolecules CY - Amsterdam, Netherlands DA - 2009-01-27 PY - 2009 AN - OPUS4-19188 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Determination of critical conditions of adsorption for chromatography of polymers N2 - Liquid chromatography (LC) at critical conditions of adsorption was used to separate various poly(ethylene oxides), poly(propylene oxides) and their copolymers. For the first time, the determination of the critical conditions by means of Ultra Performance Liquid Chromatography (UPLC) coupled to Electrospray Ionization Time-of-flight Mass Spectrometry (ESI-TOF MS) is reported. In contrast to established, mostly laborious routines to find suitable chromatographic separation conditions, this coupling enables a very fast adjustment of parameters. Similar to LC Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (LC/MALDI MS) coupling, a two-dimensional analysis of homo- and copolymers regarding its functionality type and molecular weight distribution, as well as copolymer composition, can be performed simultaneously. Furthermore, there is no need for using polymer standards for the determination of critical conditions or Size Exclusion Chromatography calibration. KW - Polymere KW - UPLC KW - ESI-Massenspektrometrie KW - Kopplung PY - 2009 U6 - https://doi.org/10.1021/ac8019784 SN - 0003-2700 SN - 1520-6882 VL - 81 IS - 1 SP - 282 EP - 287 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - Imaging mass spectrometry for examining localization of polymeric composition in matrix-assisted laser desorption/ionization samples N2 - The localization of polymeric composition in samples prepared for matrix-assisted laser desorption/ionization (MALDI) analysis has been investigated by imaging mass spectrometry. Various matrices and solvents were used for sample spot preparation of a polybutyleneglycol (PBG 1000). It was shown that in visibly homogeneous spots, prepared using the dried droplet method, separation between matrix and polymer takes place. Moreover, using -cyano-4-hydroxycinnamic acid (CCA) as matrix and methanol as solvent molecular mass separation of the polymer homologues in the spots was detectable. In contrast to manually spotted samples, dry spray deposition results in homogeneous layers showing no separation effects. KW - Imaging KW - MALDI TOF Massenspektrometrie KW - Polymere PY - 2009 U6 - https://doi.org/10.1002/rcm.3919 SN - 0951-4198 SN - 1097-0231 VL - 23 IS - 5 SP - 653 EP - 660 PB - Wiley CY - Chichester AN - OPUS4-19622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bahlmann, Arnold A1 - Falkenhagen, Jana A1 - Weller, Michael G. A1 - Panne, Ulrich A1 - Schneider, Rudolf T1 - Cetirizine as pH-dependent cross-reactant in a carbamazepine-specific immunoassay N2 - High performance liquid chromatography (HPLC) was hyphenated with a previously reported carbamazepine-specific enzyme-linked immunosorbent assay (ELISA) as a screening approach to water analysis in order to identify possible interferences from transformation products. Treated wastewater was analysed and three substances were recognized by the antibody besides carbamazepine: the metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 2-hydroxycarbamazepine plus the structurally not obviously related antihistamine cetirizine. The molar cross-reactivity against cetirizine was found to be pH-dependent and assessed to be 400% at pH 4.5 and 22% at pH 10.5. Performing the ELISA at pH 10.5 greatly improved the accuracy when carbamazepine was determined in surface and wastewater samples. KW - Immunoassay KW - ELISA KW - Cetirizin KW - Carbamazepin KW - pH-Abhängigkeit KW - Kreuzreaktivität PY - 2011 U6 - https://doi.org/10.1039/c0an00928h SN - 0003-2654 SN - 1364-5528 VL - 136 IS - 7 SP - 1357 EP - 1364 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-23546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Knop, K. A1 - Thünemann, Andreas T1 - Structure and end-group analysis of complex hexanediol-neopentylglycol-adipic acid copolyesters by matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry N2 - Sequences and end groups of complex copolyesters were determined by fragmentation analysis by means of matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry (MALDI CID MS/MS). The complexity of the crude copolyester mixture was reduced by a chromatographic separation followed by a MALDI time-of-flight (TOF) investigation of fractions. Due to overlapping compositional and end-group information a clear assignment of end groups was very difficult. However, the fragmentation of suitable precursor ions resulted in typical fragment ion patterns and, therefore, enabled a fast and unambiguous determination of the end groups and composition of this important class of polymers. KW - Fragmentierung KW - MALDI Massenspektrometrie KW - Polymere KW - MS/MS PY - 2009 U6 - https://doi.org/10.1002/rcm.4191 SN - 0951-4198 SN - 1097-0231 VL - 23 IS - 17 SP - 2768 EP - 2774 PB - Wiley CY - Chichester AN - OPUS4-20929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Copolymer characterization by coupled LC - MS/MS techniques T2 - 2010 International Chemical Congress of Pcific Basin Societies CY - Honolulu, HI, USA DA - 2010-12-15 PY - 2010 AN - OPUS4-22831 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Soulis, S. A1 - Triantou, D. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Simitzis, J. T1 - Structural analysis of biodegradable low-molecular mass copolyesters based on glycolic acid, adipic acid and 1,4 butanediol and correlation with their hydrolytic degradation N2 - Copolyesters of glycolic acid combined with adipic acid and 1,4 butanediol were synthesized, their in vitro hydrolytic degradation was studied and correlated with their structure. The hydrolytic degradation of the copolyesters was directly related with the degree of crystallinity and the diameter of the crystallites. It was found that glycolate units disturb the ordering of the butylene adipate units, which results in a decrease of the crystallinity. By comparing the hydrolysis parameters of synthesized copolyesters with those of similar aliphatic copolyesters a hydrolysis mechanism was proposed. According to this mechanism, the degradation takes place not only by the loss of end units, but also through the removal of larger segments. MALDI-TOF MS data showed that the possibility of a copolyester macromolecule forming cyclic structures correlates with the arrangement of ester groups in the macromolecules and the structure of the linear segments. KW - Biodegradable KW - Biopolymers KW - Hydrolytic degradation KW - Ft-IR KW - Matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry KW - MALDI-TOF-MS PY - 2012 U6 - https://doi.org/10.1016/j.polymdegradstab.2012.09.002 SN - 0141-3910 SN - 1873-2321 VL - 97 IS - 11 SP - 2091 EP - 2103 PB - Applied Science Publ. CY - London AN - OPUS4-26723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, C. A1 - Falkenhagen, Jana A1 - Beskers, T.F. A1 - Nguyen, L.-T.T. A1 - Wilhelm, M. A1 - Du Prez, F.E. A1 - Barner-Kowollik, C. T1 - Multi-block polyurethanes via RAFT end-group switching and their characterization by advanced hyphenated techniques N2 - The detailed characterization of poly(styrene)-b-poly(tetrahydrofuran) (pS-b-pTHF) multiblock copolymers (17800 g mol-1 ≤ Mn ≤ 46800 g mol-1) generated via urethane linkages is presented. The synthesis of the block copolymers is enabled via a mechanistic switch of the thiocarbonyl thio end group of a poly(styrene) to dihydroxyl terminated polymers that subsequently react with a diisocyanate terminated polytetrahydrofuran based prepolymer to form multiblock copolymer structures. The characterization of the multiblock copolymers and their substructures includes size exclusion chromatography (SEC), liquid chromatography at critical conditions (LCCC), nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy as well as matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. To obtain even further details of the polymer size and its composition, SEC with triple detection as well as newly developed SEC coupled online to IR spectroscopy was carried out. The quantification of the average block fractions via online SEC-IR (41–61 mol % pTHF) is in very good agreement with the results obtained via NMR spectroscopy (39–66 mol % pTHF). PY - 2012 U6 - https://doi.org/10.1021/ma301117k SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 16 SP - 6353 EP - 6362 PB - American Chemical Society CY - Washington, DC AN - OPUS4-26942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Bressler, I. T1 - Copolymer composition determined by LC-MALDI-TOF MS coupling and 'MassChrom2D' data analysis N2 - The MALDI-TOF MS analysis of copolymers very often results in complex spectra. A chromatographic separation/fractionation prior to the MALDI investigation can be advantageous since the MALDI mass spectra of fractions very often reveal well-resolved peaks of distinguishable copolymer series. For this purpose, different modes of chromatography have been applied. Chromatographic runs were transferred to MALDI targets utilizing a combined air/electrospray deposition device. Using the new MassChrom2D software, fraction-dependent 2D copolymer compositions plots were obtained providing additional information on the chromatographic mode, and enabling fast modification of conditions to increase separation. KW - Copolymer composition KW - Chromatography KW - Coupling KW - MALDI-TOF mass spectrometry PY - 2012 U6 - https://doi.org/10.1002/macp.201200169 SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2404 EP - 2411 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, C. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Barner-Kowollik, C. T1 - In-depth LCCC-(GELC)-SEC characterization of ABA block copolymers generated by a mechanistic switch from RAFT to ROP N2 - A recently introduced procedure involving a mechanistic switch from reversible addition–fragmentation chain transfer (RAFT) polymerization to ring-opening polymerization (ROP) to form diblock copolymers is applied to synthesize ABA (star) block copolymers. The synthetic steps include the polymerization of styrene with R-group designed RAFT agents, the transformation of the thiocarbonyl thio end groups into OH functionalities, and their subsequent chain extension by ROP. The obtained linear ABA poly(ε-caprolactone)-block-poly(styrene)-block-poly(ε-caprolactone) (pCL-b-pS-b-pCL) (12 500 g mol–1 ≤ Mn ≤ 33 000 g mol–1) and the star-shaped poly(styrene)-block-poly(ε-caprolactone) (Mn = 36 000 g mol–1) copolymers were analyzed by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The focus of the current study is on the detailed characterization of the ABA (star) block polymers via multidimensional chromatographic techniques specifically high performance liquid chromatography coupled to size exclusion chromatography (HPLC-SEC). In particular, we demonstrate the first time separation of poly(ε-caprolactone) (pCL) homopolymer and additionally poly(styrene) (pS) from the ABA poly(ε-caprolactone)-b-poly(styrene)-b-poly(ε-caprolactone) and star-shaped poly(styrene)-b-poly(ε-caprolactone) block copolymer utilizing critical conditions (CC) for pCL with concomitant gradient elution liquid chromatography (GELC). KW - Two-dimensional-liquid chromatography (2D-LC) KW - Liquid chromatography under critical conditions (LCCC) KW - Gradient elution liquid chromatography (GELC) KW - Soft ionization mass spectrometry (ESI, MALDI) KW - Reversible addition fragmentation chain transfer (RAFT) KW - Ring opening polymerization (ROP) PY - 2012 U6 - https://doi.org/10.1021/ma2022452 SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 1 SP - 87 EP - 99 PB - American Chemical Society CY - Washington, DC AN - OPUS4-25464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Weidner, Steffen A1 - Falkenhagen, Jana ED - Li, L. T1 - LC-MALDI MS for polymer characterization KW - Mass spectrometry KW - Polymers PY - 2010 SN - 978-0-471-77579-9 N1 - Serientitel: Chemical analysis: a series of monographs on analytical chemistry and its applications – Series title: Chemical analysis: a series of monographs on analytical chemistry and its applications VL - 175 IS - Chapter 11 SP - 247 EP - 265 PB - John Wiley & Sons AN - OPUS4-26406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Falkenhagen, Jana T1 - Combined impact of UV radiation and nitric acid on high‐density polyethylene containers as a laboratory test N2 - In a laboratory test, transparent high‐density polyethylene (HDPE) jerrycans have been exposed to both UV radiation and 55 wt‐% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The damages are compared with FTIR spectroscopy in ATR and HT‐gel permeation chromatography(GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. This is caused by the decomposition of nitric acid into nitrous gases by UV radiation, which is also observed at lower concentrations (28 wt‐%). After 6 days of laboratory exposure, this is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. The gradual increase in oxidative damage shows the reproducibility of the test. KW - Molecular mass distribution KW - High-density polyethylene KW - Nitric acid KW - UV radiation PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-550141 SN - 0894-3214 SP - 1 EP - 7 PB - John Wiley & Sons Ltd AN - OPUS4-55014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Epping, Ruben T1 - Coupling of chromatographic and spectrometric techniques for polymer characterization N2 - Coupling of chromatographic and spectrometric techniques for polymer characterization; focus topics: LCxMALDI-TOF-MS and UPLC x ESI-TOF-MS T2 - 16. Tagung des Arbeitskreises Polymeranalytik CY - Online meeting DA - 22.03.2022 KW - Liquid chromatography KW - Mass spectrometry KW - Polymers KW - Two-dimensional chromatography (2D-LC) PY - 2022 AN - OPUS4-54567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Musl, O. A1 - Sulaeva, I. A1 - Sumerskii, I. A1 - Mahler, A.K. A1 - Rosenau, T. A1 - Falkenhagen, Jana A1 - Potthast, A. T1 - Mapping of the Hydrophobic Composition of Lignosulfonates N2 - Lignosulfonates are industrial biorefinery products that are characterized by significant variability and heterogeneity in their structural composition. Typically, they exhibit high dispersities in molar mass (molar mass distribution-MMD) and in functionalities (functionality-type distribution - FTD), which crucially affect their material usage. In terms of FTD, state-of-the-art Lignin analytics still rely mainly on the determination of functional group contents, which are statistical averages with limited explanatory power. In contrast, our online hydrophobic interaction chromatography−size-exclusion chromatography 2D-LC approach combines the determination of both MMD and FTD in a single measurement to provide a comprehensive picture of the characteristic composition of industrial lignosulfonates information hitherto inaccessible by state-of-the-art lignin analytics. In this way, the complex inter - relationships between these two important structural parameters can be studied in an unprecedented manner. In this study, we reveal the considerable differences in terms of hydrophobic composition and its dispersity present in a range of different industrial lignosulfonates - data desperately needed in tailoring and refining of lignosulfonate composition for material usage. KW - Lignosulfonates KW - Amphiphilicity KW - Hydrophobic interaction chromatography KW - Two-dimensional chromatography (2D-LC) KW - Charge-to-size-ratio PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-538612 VL - 9 IS - 49 SP - 16786 EP - 16795 PB - ASC Publications AN - OPUS4-53861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - The role of transesterifications in reversible polycondensations and a reinvestigation of the Jacobson-Beckmann-Stockmayer experiments N2 - The polycondensations of adipic acid and 1,10-decanediol catalyzed by toluene sulfonic acid (TSA) were reinvestigated using MALDI TOF mass spectrometry and NMR spectroscopy. Unexpected reactions of TSA were detected along with incomplete conversion of the monomers. Furthermore, transesterification reactions of end-capped poly(1,10-decanediol adipate) and end-capped poly(ε-caprolactone) catalyzed by TSA were studied. Despite the quite different (ionic) reaction mechanisms, it was found that for polycondensations performed in bulk intermolecular transesterification is more efficient than the intramolecular “back-biting”; this scenario was not considered in the Jacobson–Stockmayer theory of reversible polycondensations. These results also confirm that the Jacobson–Stockmayer explanation of reversible polycondensations solely on the basis of ring chain equilibration is not only devoid of any experimental evidence, but also in contradiction to the results elaborated in this work. KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-543402 SN - 1759-9962 SP - 1 EP - 9 PB - RSC Publ. CY - Cambridge AN - OPUS4-54340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - Reversible Polycondensations outside the Jacobson-Stockmayer Theory and a New Concept of Reversible Polycondensations N2 - L-Lactide was polymerized with tin(II)acetate, tin(II)2-ethyl hexanoate, diphenyltin dichloride and dibutyltin bis(pentafluorophenoxide) at 130 °C in bulk. When an alcohol was added as initiator, linear chains free of cycles were formed having a degree of polymerization (DP) according to the lactide/initiator (LA/In) ratio. Analogous polymerizations in the absence of an initiator yielded high molar mass cyclic polylactides. Quite similar results were obtained when ε-caprolactone was polymerized with or without initiator. Several transesterification experiments were conducted at 130 °C, either with polylactide or poly(ε-caprolactone) indicating that several transesterification mechanisms are operating under conditions that do not include formation of cycles by back-biting. Furthermore, reversible polycondensations (revPOCs) with low or moderate conversions were found that did not involve any kind of cyclization. Therefore, These results demonstrate the existence of revPOCs, which do neither obey the theory of irreversible polycondensation as defined by Flory nor the hypothesis of revPOCs as defined by Jacobson and Stockmayer. A new concept encompassing any kind of revPOCs is formulated in the form of a “polycondensation triangle”. KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-530831 VL - 12 IS - 35 SP - 5003 EP - 5016 PB - Royal Society for Chemistry AN - OPUS4-53083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fink, Friedrich A1 - Emmerling, Franziska A1 - Falkenhagen, Jana T1 - Identification and Classification of Technical Lignins by means of Principle Component Analysis and k-Nearest Neighbor Algorithm N2 - The characterization of technical lignins is a key step for the efficient use and processing of this material into valuable chemicals and for quality control. In this study 31 lignin samples were prepared from different biomass sources (hardwood, softwood, straw, grass) and different pulping processes (sulfite, Kraft, organosolv). Each lignin was analysed by attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. Statistical analysis of the ATR-FT-IR spectra by means of principal component analysis (PCA) showed significant differences between the lignins. Hence, the samples can be separated by PCA according to the original biomass. The differences observed in the ATR-FT-IR spectra result primarily from the relative ratios of the p-hydroxyphenyl, guaiacyl and syringyl units. Only limited influence of the pulping process is reflected by the spectral data. The spectra do not differ between samples processed by Kraft or organosolv processes. Lignosulfonates are clearly distinguishable by ATR-FT-IR from the other samples. For the classification a model was created using the k-nearest neighbor (k NN) algorithm. Different data pretreatment steps were compared for k=1…20. For validation purposes, a 5-fold cross-validation was chosen and the different quality criteria Accuracy (Acc), Error Rate (Err), Sensitivity (TPR) and specificity (TNR) were introduced. The optimized model for k=4 gives values for Acc = 98.9 %, Err = 1.1 %, TPR = 99.2 % and TNR = 99.6 %. KW - Classification KW - PCA KW - K-nearest neighbor KW - FT-IR KW - Technical lignin PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-533855 VL - 1 IS - 8 SP - 350 EP - 396 PB - Wiley-VCH GmbH AN - OPUS4-53385 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Falkenhagen, Jana A1 - Kricheldorf, H. R. T1 - SnOct2-catalyzed and alcohol-initiated ROPs of L-lactide – About the influence of initiators on chemical reactions in the melt and the solid state N2 - SnOct2 (Sn(II) 2-ethylhexanoate) catalyzed ROPs of L-lactide were performed in bulk with eight different alcohols as initiators. The time was varied between 1 h and 24 h for all initiators. For two initiators the temperature was also lowered to 115 ◦C. Even-numbered chains were predominantly formed in all polymerizations at short times, but the rate of transesterification (e.g. even/odd equilibration) and the molecular weight distribution were found to depend significantly on the nature of the initiator. Observed transesterification reactions also continued in solid poly (L-lactide), and with the most active initiator, almost total equilibration was achieved even at 130 ◦C. This means that all chains including those of the crystallites were involved in transesterification reactions proceeding across the flat surfaces of the crystallites. The more or less equilibrated crystalline polylactides were characterized by DSC and SAXS measurements with regard to their melting temperature (Tm), crystallinity and crystal thickness. KW - Polylactide KW - MALDI-TOF MS KW - Crystallization KW - Catalysts KW - SAXS PY - 2021 U6 - https://doi.org/10.1016/j.eurpolymj.2021.110508 VL - 153 SP - 110508 PB - Elsevier Ltd. AN - OPUS4-52633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Polymer characterisation by multidimensional techniques with focus on LC - MALDI/ESI-TOF-MS N2 - Since the first LC/ ESI-MS experiment of the Nobel prize winner John B. Fenn in 1984, the coupling of liquid chromatographic to mass spectrometric techniques gained a continuous rapid development. The lecture will give a general survey of different LC separation techniques as size exclusion chromatography (SEC), liquid adsorption chromatography (LAC), liquid chromatography at critical conditions (LCCC) and gradient elution liquid chromatography (GELC) combined with Matrix assisted Laser Desorption Ionization (MALDI) respectively Electrospray Ionization (ESI) Time of Flight (TOF) mass spectrometry. Often the deficiencies of stand-alone methods can be bridged. LC, blind to structural information needs mass spectrometry as one of the most powerful detectors able to give detailed information on e.g. the repeat units, functionalization or copolymer composition of the chromatographic separated constituents. A separation prior to MS reduces the polydispersity which is one of the reasons for failing of MS. Also problems with different ionization probabilities in complex mixtures can partly be overcame. On the basis of different examples on- and offline coupling principles will be compared and the pros and cons of both mass spectrometric techniques will be discussed. Recently, MALDI imaging techniques in coupling with chromatography have become interesting e.g. for visualization of copolymer composition. T2 - International Symposium GPC/SEC and Related Techniques CY - Amsterdam, The Netherlands DA - 26.09.2016 KW - Polymers KW - Liquid chromatography KW - MALDI-TOF-MS KW - ESI-TOF-MS PY - 2016 AN - OPUS4-37629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Christina A1 - Zorn, R. A1 - Emmerling, Franziska A1 - Falkenhagen, Jana A1 - Frick, B. A1 - Huber, P. A1 - Schönhals, Andreas T1 - Vibrational density of states of triphenylene based discotic liquid crystals: dependence on the length of the alkyl chain N2 - The vibrational density of states of a series of homologous triphenylene-based discotic liquid crystals HATn (n = 5, 6, 8, 10, 12) depending on the length of the aliphatic side chain is investigated by means of inelastic neutron scattering. All studied materials have a plastic crystalline phase at low temperatures, followed by a hexagonally ordered liquid crystalline phase at higher temperatures and a quasi isotropic phase at the highest temperatures. The X-ray scattering pattern for the plastic crystalline phase of all materials shows a sharp Bragg reflection corresponding to the intercolumnar distance in the lower q-range and a peak at circa 17 nm-1 related to intracolumnar distances between the cores perpendicular to the columns as well as a broad amorphous halo related to the disordered structure of the methylene groups in the side chains in the higher q-range. The intercolumnar distance increases linearly with increasing chain length for the hexagonal columnar ordered liquid crystalline phase. A similar behaviour is assumed for the plastic crystalline phase. Besides n = 8 all materials under study exhibit a Boson peak. With increasing chain length, the frequency of the Boson peak decreases and its intensity increases. This can be explained by a self-organized confinement model. The peaks for n = 10, 12 are much narrower than for n = 5, 6 which might imply the transformation from a rigid system to a softer one with increasing chain length. Moreover the results can also be discussed in the framework of a transition from an uncorrelated to a correlated disorder with increasing n where n = 8 might be speculatively considered as a transitional state. KW - X-ray scattering KW - Neutron scattering KW - Differential scanning calorimetry PY - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-304789 SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 16 SP - 7324 EP - 7333 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Is Liquid Chromatography at Critical Conditions already a routine technique? T2 - Int. Symp. on GPC/SEC and Related Techniques CY - Frankfurt/Main DA - 2014-09-30 PY - 2014 AN - OPUS4-32000 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter T1 - Characterization of silicon polymers (silsesquioxanes, dendrimers and copolymers) by means of different modes of Liquid Chromatography and MALDI-TOF-MS T2 - 11th International Symposium on Polymer Analysis and Characterization CY - Santa Margherita Ligure, Italien DA - 1998-05-25 PY - 1999 N1 - Serientitel: International journal of polymer analysis and characterization – Series title: International journal of polymer analysis and characterization IS - 5.1999,3 PB - Gordon and Breach CY - St. Helier AN - OPUS4-19053 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Mix, Renate A1 - Falkenhagen, Jana A1 - Schulze, Rolf-Dieter A1 - Gerstung, Vanessa A1 - Friedrich, Jörg Florian ED - K.L. Mittal, T1 - Plasma homo- and copolymerization of allyl alcohol and styrene KW - Plasma polymerization KW - Surface functionalization KW - Molar masses PY - 2009 SN - 978-90-04-16590-8 VL - 5 SP - 317 EP - 340 PB - Koninklijke Brill NV CY - Leiden, The Netherlands AN - OPUS4-19606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinylpyrrolidone and vinyl acetate, 2 - chromatographic separation and analysis by MALDI-TOF and FT-IR coupling N2 - PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI-TOF MS, our data proved a non-ideal RAFT polymerization. KW - Amphiphiles KW - Block copolymers KW - Liquid chromatography KW - MALDI KW - Reversible addition fragmentation chain transfer (RAFT) KW - Liquid adsorption chromatography at critical conditions KW - Gradient chromatography KW - MALDI-TOF mass spectrometry KW - Hyphenated techniques KW - Mechanism of polymerization PY - 2010 U6 - https://doi.org/10.1002/macp.201000044 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 15 SP - 1678 EP - 1688 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, C. A1 - Falkenhagen, Jana A1 - Barner-Kowollik, C. T1 - An efficient avenue to poly(styrene)-block-poly(Epsilon-caprolactone) polymers via switching from RAFT tio hydroxyl functionality: synthesis and characterization KW - 2D-liquid chromatography KW - End group transformation KW - LACCC-SEC KW - Reversible addition fragmentation chain transfer KW - Ring-opening polymerization KW - soft ionization mass spectrometry PY - 2011 U6 - https://doi.org/10.1002/pola.24299 SN - 0360-6376 SN - 0887-624X VL - 49 IS - 1 SP - 1 EP - 10 PB - Wiley CY - Hoboken, NJ AN - OPUS4-22894 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gruendling, T. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Barner-Kowollik, C. T1 - Mass spectrometry in polymer chemistry: a state-of-the-art up-date N2 - Two decades after the introduction of matrix assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), soft ionization mass spectrometry represents a powerful toolset for the structural investigation of synthetic polymers. The present review highlights the current state-of-the-art, covering the latest developments of novel techniques, enabling instrumentation as well as the important applications of soft ionization MS from the beginning of 2008. Special attention is paid to the role that soft ionization MS has played in the mechanistic investigation of radical polymerization processes since 2005. KW - Polymerization mechanisms KW - Mass spectrometry KW - LC-MS coupling PY - 2010 U6 - https://doi.org/10.1039/b9py00347a SN - 1759-9954 SN - 1759-9962 VL - 1 IS - 5 SP - 599 EP - 617 AN - OPUS4-21906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, M. A1 - Glassner, M. A1 - Gruendling, T. A1 - Schmid, Christina A1 - Falkenhagen, Jana A1 - Barner-Kowollik, C. T1 - Facile conversion of RAFT polymers into hydroxyl functional polymers: a detailed investigation of variable monomer and RAFT agent combinations N2 - We report the systematic investigation of a recently introduced one-pot radical transformation of methacrylate and acrylate-type polymers prepared via reversible addition fragmentation chain transfer (RAFT) polymerization into hydroxyl functional polymers. The simple reaction procedure involves stirring a solution of the RAFT functional polymer and an azo-initiator in tetrahydrofuran at elevated temperatures (T = 60 °C) in the presence of ambient air. Subsequent reduction of the formed hydroperoxide functional polymers to hydroxyl functional polymers is achieved in a one-pot procedure using triphenylphosphine. Polymers investigated in the current study are poly(methyl acrylate) (pMA), poly(butyl acrylate) (pBA), poly(isobornyl acrylate) (piBoA) and poly(tert-butyl acrylate) (ptBA) carrying a dithiobenzoate or phenyldithioacetate end terminius as well as a symmetrical trithiocarbonate mid chain function. Quantitative conversion into the hydroperoxyl and hydroxyl terminated product is observed when trithiocarbonate functional polymers are employed. In the case of dithiobenzoate and phenyldithioacetate functional acrylic polymers, some minor side products due to the oxidation of the RAFT end-group are generated. Size exclusion chromatography (SEC) and size exclusion chromatography–electrospray mass spectrometry (SEC-ESI-MS) were employed to monitor the progress of the reaction and to investigate the proposed reaction mechanism for the model polymers. When trithiocarbonate functional polymers are employed in the transformation reaction, the SEC analysis shows a bisection of the initial Mn. Collision induced dissociation (CID) MS experiments of the intermediate reaction products were conducted to gain in-depth information about the chemical structure. The new backbone linked hydroxyl group provides a versatile anchor for chemical end-group conversions and conjugation reactions with RAFT prepared polymers, alleviating problems with the rather limited ability of the dithioester end-group to undergo non-radical transformations. KW - Polymers KW - RAFT KW - SEC/ESI-mass spectrometry KW - CID-MS PY - 2010 U6 - https://doi.org/10.1039/b9py00273a SN - 1759-9954 SN - 1759-9962 VL - 1 IS - 5 SP - 634 EP - 644 AN - OPUS4-21907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Hyphenated Characterization TEchniques for Polymers: From LC/MALDI- and UPLC/ESI-TOF-MS to CID tandem mass spectrometry T2 - 11th Int. Symp. on Hyphenated Techniques in Chromatography CY - Amsterdam, Netherlands DA - 2010-01-27 PY - 2010 AN - OPUS4-21965 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Pfeifer, Dietmar A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinyl pyrrolidone and vinyl acetate, 1 - analysis of copolymer composition, end groups, molar masses and molar mass distributions N2 - New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. 13C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, 13C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism. KW - Amphiphiles KW - Block copolymers KW - Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) KW - N-vinyl pyrrolidone KW - Reversible addition/fragmentation chain transfer (RAFT) PY - 2010 U6 - https://doi.org/10.1002/macp.200900466 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 8 SP - 869 EP - 878 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-21905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Schmid, Christina T1 - Hyphenated techniques for copolymer characterization with the focus on 2D-LC / mass spectrometry T2 - 5th Int.Symp. on the Separation and Characterization of Natural and Synthetic Macromolecules CY - Amsterdam, Netherlands DA - 2011-01-25 PY - 2011 AN - OPUS4-22657 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, B.V.K.J. A1 - Fechler, N. A1 - Falkenhagen, Jana A1 - Lutz, J.-F. T1 - Controlled folding of synthetic polymer chains through the formation of positionable covalent bridges N2 - Covalent bridges play a crucial role in the folding process of sequence-defined biopolymers. This feature, however, has not been recreated in synthetic polymers because, apart from some simple regular arrangements (such as block co-polymers), these macromolecules generally do not exhibit a controlled primary structure—that is, it is difficult to predetermine precisely the sequence of their monomers. Herein, we introduce a versatile strategy for preparing foldable linear polymer chains. Well-defined polymers were synthesized by the atom transfer radical polymerization of styrene. The controlled addition of discrete amounts of protected maleimide at precise times during the synthesis enabled the formation of polystyrene chains that contained positionable reactive alkyne functions. Intramolecular reactions between these functions subsequently led to the formation of different types of covalently folded polymer chains. For example, tadpole (P-shaped), pseudocyclic (Q-shaped), bicyclic (8-shaped) and knotted (α-shaped) macromolecular origamis were prepared in a relatively straightforward manner. KW - Copolymerization KW - Chain folding KW - SEC KW - NMR KW - FT-IR KW - LAC KW - MALDI PY - 2011 U6 - https://doi.org/10.1038/NCHEM.964 SN - 1755-4330 SN - 1755-4349 VL - 3 SP - 234 EP - 238 PB - Nature Publishing Group CY - London, UK AN - OPUS4-23888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Thünemann, Andreas T1 - Structure and end group analysis of complex polymers by LC/MALDI/ESI-TOF CID MS/MS T2 - 11th Bayreuther Polymer Symposium CY - Bayreuth, Germany DA - 2009-09-13 PY - 2009 AN - OPUS4-19988 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Hyphenated characterization techniques for polymer analysis: from SEC-ESI-MS to 2D HPLC/SEC chromatography T2 - Controlled/Living Radical Polymerizations: Latest Trends in Synthesis, Characterization and Industrial Applications CY - Houffalize, Belgium DA - 2009-09-17 PY - 2009 AN - OPUS4-20000 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moser, Marko A1 - Schneider, Ralf A1 - Behnke, Thomas A1 - Schneider, Thomas A1 - Falkenhagen, Jana A1 - Resch-Genger, Ute T1 - Ellman’s and aldrithiol assay as versatile and complementary tools for the quantification of thiol groups and ligands on nanomaterials N2 - Simple, fast, and versatile methods for the quantification of thiol groups are of considerable interest not only for protein analysis but also for the characterization of the surface chemistry of nanomaterials stabilized with thiol ligands or bearing thiol groups for the subsequent (bio-) functionalization via maleimide−thiol chemistry. Here, we compare two simple colorimetric assays, the widely used Ellman’s assay performed at alkaline pH and the aldrithiol assay executed at acidic and neutral pH, with respect to their potential for the quantification of thiol groups and thiol ligands on different types of nanoparticles like polystyrene nanoparticles, semiconductor nanocrystals (SC NC), and noble metal particles, and we derive criteria for their use. In order to assess the underlying reaction mechanisms and to obtain stoichiometry factors mandatory for reliable thiol quantification, both methods were studied photometrically and with electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), thereby demonstrating the influence of different thiols on the reaction mechanism. Our results underline the suitability of both methods for the quantification of directly accessible thiol groups or ligands on the surface of 2D- and 3D-supports, here exemplarily polystyrene nanoparticles. Moreover, we could derive strategies for the use of these simple assays for the determination of masked (i.e., not directly accessible) thiol groups like disulfides such as lipoic acid and thiol stabilizing ligands coordinatively bound to Cd and/or Hg surface atoms of II/VI and ternary SC NC and to gold and silver nanoparticles. KW - Nanoparticles KW - Ligands KW - Ellman KW - Aldrithiol KW - Quantification PY - 2016 U6 - https://doi.org/10.1021/acs.analchem.6b01798 SN - 0003-2700 SN - 1520-6882 VL - 88 IS - 17 SP - 8624 EP - 8631 PB - ACS Publications CY - Washington AN - OPUS4-37561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Polymer Characterization by Multidimensional Techniques T2 - Analysis and Characterization of Polymers CY - Toulouse, France DA - 2015-09-07 PY - 2015 AN - OPUS4-34108 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hoskins, Jessica A1 - Falkenhagen, Jana A1 - Weidner, Steffen ED - Udomkichdecha, W. ED - Böllinghaus, T. ED - Manonukul, A. ED - Lexow, J. T1 - Characterization of randomly branched polymers utilizing liquid chromatography and mass spectrometry N2 - Branching in polymers is an important way to modify the materials properties, however the characterization of random branching in polymeric materials is a challenge in polymer analysis. In this work, liquid adsorption chromatography methods are developed for a commercially available hyperbranched polyester (Boltorn™). This Chromatographie techniques was then coupled to offline MALDI-TOF MS analysis, a first in the analysis of randomly branched polymers. The coupling of these two techniques provides superior MALDI-TOF spectra, enabling the easy identification of structural subdistributons based on theoretical molecular weight. Detailed analysis of the MALDI-TOF spectra shows that these Chromatographie conditions separate cyclic Boltorn polymers (with no core molecule) from non-cyclic polymers (with core molecule), and these are the only two architectures observed. MALDI MS also confirms that the Chromatographie Separation mode is adsorption, but further analysis is needed to determine if there is a Separation by degree of branching. KW - Hyperbranched polyesters KW - Polymer mass spectrometry KW - Polymer chromatography KW - Liquid adsorption chromatography KW - MALDI-TOF MS KW - Carbon capture KW - Climate change KW - Lubricant KW - Micro manufacturing KW - Multiphysics simulations KW - WMRIF PY - 2014 SN - 978-3-319-11339-5 SN - 978-3-319-11340-1 SP - 1 EP - 10 PB - Springer AN - OPUS4-32519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Purohit, Purv A1 - Kang, N. A1 - Wang, D.-Y. A1 - Falkenhagen, Jana A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Schönhals, Andreas T1 - Structure-property relationships of nanocomposites based on polylactide and MgAl layered double hydroxides N2 - Nanocomposites based on poly(ʟ-lactide) (PLA) and organically modified MgAl Layered Double Hydroxides (MgAl-LDH) were prepared by melt blending and investigated by a combination of Differential Scanning Calorimetry (DSC), Small- and Wide-Angle X-ray Scattering (SAXS, WAXS), and dielectric spectroscopy (BDS). Scanning microfocus SAXS investigations show that the MgAl-LDH is homogeneously distributed in the matrix as stacks of 6 layers and/or partly exfoliated layers. DSC and WAXS show that the degree of crystallinity decreases linearly with the content of LDH. The extrapolation of the dependencies (DSC and WAXS) to zero estimates a limiting concentration of LDH CCri of ca. 21 wt% where the crystallization of PLA is completely suppressed by the nanofiller. The dielectric behavior of neat PLA show two relaxation regions, a β-relaxation at low temperatures related to localized fluctuations and the α-relaxation at higher temperatures due to the dynamic glass transition. The dielectric spectra of the nanocomposites show several additional relaxation processes compared to neat PLA which are discussed in detail. For the nanocomposites around 260 K (ƒ = 1 kHz) an additional process is observed which intensity increases with increasing concentration of LDH. This process is mainly attributed to the exchanged dodecylbenzene sulfonate (SDBS) molecules which are adsorbed at the LDH layers and form a mixed phase with the polymer close to the layers and stacks. An analysis of this process provides information about the molecular dynamics in the interfacial region between the LDH layers and the PLA matrix which reveal glassy dynamics in this region. In the temperature range around 310 K (ƒ = 1 kHz) a further process is observed. Its relaxation rate has an unusual saddle-like temperature dependence. It was assigned to rotational fluctuations of water molecules in a nanoporous environment provided by the LDH filler. Above the glass transition temperature a further process is observed at temperatures above. It is related to Maxwell/Wagner/Sillars polarization due to the blocking of charges at the nanofiller. KW - Polymer based nanocomposites KW - Polylactide KW - Layered double hydroxides KW - Dielectric spectroscopy PY - 2015 U6 - https://doi.org/10.1016/j.eurpolymj.2015.05.008 SN - 0014-3057 SN - 1873-1945 VL - 68 SP - 338 EP - 354 PB - Elsevier CY - Oxford AN - OPUS4-33257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - LC-MS Coupling of synthetic polymers - 30 years after John B. Fenn T2 - Int. Symp. on the Sep. and Charact. of Natural and Synthetic Macromolecules (SCM-7) CY - Amsterdam, The Netherlands DA - 2015-01-27 PY - 2015 AN - OPUS4-32503 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Characterization of co (polyamide)s N2 - Charactrization of Co(polyamide)s Molar mass distribution; Functionalization; supression of end group effects in favor of sequence distribution analysis; Evidence of of randomization with increasing reaction time T2 - Polyamide Meeting, DSM CY - Sittard, The Netherlands DA - 20.04.2018 KW - Liquid chromatography KW - Mass spectrometry of polymers PY - 2018 AN - OPUS4-44747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epping, Ruben A1 - Panne, Ulrich A1 - Falkenhagen, Jana T1 - Power of ultra performance liquid chromatography/electrospray ionization-MS reconstructed ion chromatograms in the characterization of small differences in polymer microstructure N2 - From simple homopolymers to functionalized, 3-dimensional structured copolymers, the complexity of polymeric materials has become more and more sophisticated. With new applications for instance in the semiconductor or pharmaceutical industry, the requirements for the characterization have risen with the complexity of the used polymers. For each additional distribution, an additional dimension in analysis is needed. Small, often isomeric heterogeneities in topology or microstructure can usually not be simply separated chromatographically or distinguished by any common detector, but affect the properties of materials significantly. For a drug delivery system for example, the degree of branching and branching distribution is crucial for the formation of micelles. Instead of a complicated, time consuming and/or expensive 2d-chromatography or ion mobility spectrometry (IMS) method, that also has its limitations, in this work a simple approach using size exclusion chromatography (SEC) coupled with electrospray ionization mass spectrometry (ESI) is proposed. The online coupling allows the analysis of reconstructed ion chromatograms (RIC) of each degree of polymerization. While a complete separation often cannot be achieved, the derived retention times and peak widths lead to information on the existence and dispersity of heterogeneities. Although some microstructural heterogeneities like short chain branching can for large polymers be characterized with methods such as light scattering, for oligomers where the heterogeneities just start to form and their influence is at the maximum, they are inaccessible with these methods. It is also shown, that with a proper calibration even quantitative information can be obtained. This method is suitable to detect small differences in e. g. branching, 3d-structure, monomer sequence or tacticity and could potentially be used in routine analysis to quickly determine deviations. KW - Polymer KW - Microstructure KW - UPLC KW - ESI-TOF-MS KW - Reconstructed ion chromatograms PY - 2018 U6 - https://doi.org/10.1021/acs.analchem.7b05214 SN - 0003-2700 SN - 1520-6882 VL - 90 IS - 5 SP - 3467 EP - 3474 PB - ACS Publ. CY - Washington, DC AN - OPUS4-44423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baumann, Maria A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Wold, C. A1 - Uliyanchenko, E. T1 - Characterization of copolymers of polycarbonate and polydimethylsiloxane by 2D chromatographic separation, MALDI-TOF mass spectrometry, and FTIR spectroscopy N2 - The structure and composition of polycarbonate polydimethylsiloxane copolymer (PC-co-PDMS) was investigated by applying various analytical approaches including chromatographic separation methods, spectrometric, and spectroscopic detection techniques. In particular, size exclusion chromatography (SEC) and liquid adsorption chromatography operating at different conditions (e.g. using gradient solvent systems) were used to achieve separations according to molar mass and functionality distribution. The coupling of both techniques resulted in fingerprint two-dimensional plots, which could be used to easily compare different copolymer batches. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry was applied for structural investigations. The different ionization behavior of both comonomers, however, strongly limited the applicability of this technique. In contrast to that, Fourier-transform Infrared (FTIR) spectroscopy could be used to quantify the amount of PDMS in the copolymer at different points in the chromatogram. The resulting methodology was capable of distinguishing PC-co-PDMS copolymer from PC homopolymer chains present in the material. KW - FTIR KW - Liquid chromatography KW - Mass spectrometry KW - Gradient elution KW - Polycarbonate-co-dimethylsiloxane copolymer PY - 2020 U6 - https://doi.org/10.1080/1023666X.2020.1820170 VL - 25 IS - 7 SP - 1 EP - 12 PB - Taylor & Francis AN - OPUS4-51369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Characterization of co (polyamide)s N2 - Characterization problems of technically relevant copolyamides applying size exclusion chromatography, interaction chromatography and their combination with MALDI-TOF-MS will be discussed. T2 - 23. Kolloquium Massenspektrometrie und synthetische Polymere CY - Berlin, Germany DA - 14.05.2019 KW - LCCC KW - Mass spectrometry of polymers KW - SEC KW - LC / MALDI-TOF-MS coupling PY - 2019 AN - OPUS4-48221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Shedding Light into Polymer Microstructure N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. Nowadays a wide range of different analytical separation techniques and multi-detection possibilities are available. The challenge consists in a clever combination of these techniques coordinated with the heterogeneity to be investigated. A number of applications will be presented from e.g. topology elucidation of branched EO-PO “academic” copolymers to copolymer composition of partially broadly distributed progressively tailored “industrial relevant” copolymers consisting of e.g. polyamides, polycarbonates and polysiloxanes. Multidimensional separation techniques will be demonstrated with focus on mass spectrometric detection techniques (ESI-/MALDI-TOF-MS) coupled online or semi-online to prior separation. T2 - FAST 2019, COAST Community of Innovation CY - Veldhoven, The Netherlands DA - 21.05.2019 KW - LCCC KW - Mass spectrometry of polymers KW - SEC KW - LC x MALDI/ESI-TOF-MS coupling PY - 2019 AN - OPUS4-48222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Coupling of chromatographic and spectrometric techniques for polymer characterization N2 - Presentation of coupling of polymer chromatography and polymer mass spectrometry based on different examples. T2 - Kolloquium CY - Universität für Bodenkultur, Wien, Austria DA - 14.06.2019 KW - LCCC KW - Mass spectrometry of polymers KW - LC x MALDI/ESI-TOF-MS KW - Liquid chromatography of polymers PY - 2019 AN - OPUS4-48223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epping, Ruben A1 - Falkenhagen, Jana A1 - Panne, Ulrich A1 - Hiller, W. A1 - Gruendling, T. A1 - Staal, B. A1 - Lang, C. A1 - Lamprou, A. T1 - Simultaneous characterization of poly(acrylic acid) andpolysaccharide polymers and copolymers N2 - Copolymer products that result from grafting acrylic acid and other hydrophilicmonomers onto polysaccharides have recently gained significant interest in researchand industry. Originating from renewable sources, these biodegradable, low toxicity,and polar copolymer products exhibit potential to replace polymers from fossil sourcesin several applications and industries. The methods usually employed to character-ize these copolymers are, however, quite limited, especially for the measurement ofbulk properties. With more sophisticated applications, for example, in pharmaceu-tics requiring a more detailed analysis of the chemical structure, we describe a newapproach for this kind of complex polymers. Our approach utilizes chromatographyin combination with several detection methods to separate and characterize reactionproducts of the copolymerization of acrylic acid and chemically hydrolyzed starch.These samples consisted of a mixture of homopolymer poly (acrylic acid), homopoly-mer hydrolyzed starch, and – in a lower amount – the formed copolymers. Several chro-matographic methods exist that are capable of characterizing either poly (acrylic acid)or hydrolyzed starch. In contrast, our approach offers simultaneous characterization ofboth polymers. The combination of LC and UV/RI offered insight into the compositionand copolymer content of the samples. Size exclusion chromatography experimentsrevealed the molar mass distribution of homopolymers and copolymers. FTIR inves-tigations confirmed the formation of copolymers while ESI-MS gave more details onthe end groups of hydrolyzed starches and poly (acrylic acids). Evidence of copolymerstructures was obtained through NMR measurements. Finally, two-dimensional chro-matography led to the separation of the copolymers from both homopolymers as wellas the additional separation of sodium clusters. The methods described in this work area powerful toolset to characterize copolymerization products of hydrolyzed starch andpoly(acrylic acid). Together, our approach successfully correlates the physicochemicalproperties of such complex mixtures with their actual composition. KW - 2D chromatography KW - LC-MS KW - SEC KW - Renewable copolymers KW - Grafting PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-508873 SP - 1 EP - 12 PB - Wiley-VCH Verlag-GmbH&Co. KGaA CY - Weinheim AN - OPUS4-50887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, J.L. A1 - Lutomski, C.A. A1 - El-Baba, T.J. A1 - Siriwardena-Mahanama, B.N. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Allen, M. J. A1 - Trimpin, S. T1 - Matrix-assisted ionization-ion mobility spectrometry-mass spectrometry: Selective analysis of a europium-PEG complex in a crude mixture N2 - The analytical utility of a new and simple to use ionization method, matrix-assisted ionization (MAI), coupled with ion mobility spectrometry (IMS) and mass spectrometry (MS) is used to characterize a 2-armed europium(III)-containing poly(ethylene glycol) (Eu-PEG) complex directly from a crude sample. MAI was used with the matrix 1,2-dicyanobenzene, which affords low chemical background relative to matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI). MAI provides high ion abundance of desired products in comparison to ESI and MALDI. Inductively coupled plasma-MS measurements were used to estimate a maximum of 10% of the crude sample by mass was the 2-arm Eu-PEG complex, supporting evidence of selective ionization of Eu-PEG complexes using the new MAI matrix, 1,2-dicyanobenzene. Multiply charged ions formed in MAI enhance the IMS gas-phase separation, especially relative to the singly charged ions observed with MALDI. Individual components are cleanly separated and readily identified, allowing characterization of the 2-arm Eu-PEG conjugate from a mixture of the 1-arm Eu-PEG complex and unreacted starting materials. Size-exclusion chromatography, liquid chromatography at critical conditions, MALDI-MS, ESI-MS, and ESI-IMS-MS had difficulties with this analysis, or failed. KW - Matrix-assisted ionization ion mobility spectrometry mass spectrometry KW - Europium KW - Poly(ethylene glycol) KW - Size-exclusion chromatography KW - Liquid chromatography at critical conditions KW - Electrospray ionization KW - Matrix-assisted laser desorption/ionization KW - Inductively coupled plasma-mass spectrometry KW - ESI KW - MALDI KW - SEC PY - 2015 U6 - https://doi.org/10.1007/s13361-015-1233-8 SN - 1044-0305 VL - 26 IS - 12 SP - 2086 EP - 2095 PB - Elsevier CY - New York, NY AN - OPUS4-35283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Matzen, Melissa A1 - Radke, Wolfgang T1 - Structure Analysis of Oligomers by Online UHPLC/ ESI-TOF-MS T2 - ANAKON 2015 CY - Graz, Austria DA - 2015-03-23 PY - 2015 AN - OPUS4-32936 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Liquid Chromatography at Critical Conditions - advantages and shortcomings T2 - Arbeitskreis Polymeranalytik CY - Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF Darmstadt DA - 2015-03-20 PY - 2015 AN - OPUS4-32937 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moser, Marko A1 - Behnke, Thomas A1 - Hamers-Allin, Carolina A1 - Klein-Hartwig, Karin A1 - Falkenhagen, Jana A1 - Resch-Genger, Ute T1 - Quantification of PEG-maleimide ligands and coupling efficiencies on nanoparticles with Ellman's reagent N2 - The surface modification of nanometer- and micrometer-sized particles and planar substrates with polyethylene glycol (PEG) ligands of varying length is a very common strategy to tune the hydrophilicity and biocompatibility of such materials, minimize unspecific interactions, improve biofunctionalization efficiencies, and enhance blood circulation times. Nevertheless, simple methods for the quantification of PEG ligands are comparatively rare. Here, we present a new concept for the quantification of PEG ligands for maleimide-functionalized PEG molecules and the determination of PEG coupling efficiencies, exploiting the quantitative reaction of maleimide with ʟ-cysteine, and the subsequent determination of the unreacted thiol with the photometric Ellman's test. This is shown for heterobifunctional PEG spacers of varying length and amino-functionalized polystyrene nanoparticles (PS NP) without and with differently charged encoding dyes. The reaction of ʟ-cysteine with the Ellman's reagent was monitored photometrically and with electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) to derive the reaction mechanism and to obtain the stoichiometry factor for ʟ-cysteine quantification. Mass balances and quantification of ʟ-cysteine via its sulfur concentration using elemental analysis and inductively coupled plasma mass spectrometry (ICP-MS) confirmed the accuracy and reliability of this approach that can be extended to other surface groups and ligands. KW - Photometric assay KW - Surface analysis KW - Nanoparticle KW - Polyethylene glycol KW - PEG quantification KW - Ellman's test PY - 2015 U6 - https://doi.org/10.1021/acs.analchem.5b02173 SN - 0003-2700 SN - 1520-6882 VL - 87 IS - 18 SP - 9376 EP - 9383 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chapartegui-Arias, Ander A1 - Villajos Collado, José Antonio A1 - Myxa, Anett A1 - Beyer, Sebastian A1 - Falkenhagen, Jana A1 - Schneider, Rudolf A1 - Emmerling, Franziska T1 - Covalently Fluorophore-Functionalized ZIF‑8 Colloidal Particles as a Sensing Platform for Endocrine-Disrupting Chemicals Such as Phthalates Plasticizers N2 - We present the optical sensing of phthalate Esters (PAEs), a group of endocrine-disrupting chemicals. The sensing takes place as changes in the fluorescence emission intensity of aminopyrene covalently bound to the organic ligands of the metal−organic framework compound ZIF-8. In the presence of PAEs, a quenching of the fluorescence emission is observed. We evaluated strategies to engineer colloidal size distribution of the sensing particles to optimize the sensory response to PAEs. A thorough characterization of the modified ZIF-8 nanoparticles included powder X-ray diffractometry, transmission electron microscopy, high-performance liquid chromatography, and photophysical characterization. The presented capability of the fluorophore-functionalized ZIF-8 to sense PAEs complements established methods such as chromatography-based procedures, which cannot be used on-site and paves the way for future developments such as hand-held quick sensing devices. KW - Sensing KW - MOF PY - 2019 U6 - https://doi.org/10.1021/acsomega.9b01051 VL - 4 IS - 17 SP - 17090 EP - 17097 PB - ACS AN - OPUS4-49562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Wachtendorf, Volker A1 - Elert, Anna Maria A1 - Falkenhagen, Jana A1 - Becker, Roland A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Tschiche, Harald A1 - Reinsch, Stefan A1 - Weidner, Steffen ED - Scholz, Philipp T1 - Analytical toolset to characterize polyurethanes after exposure to artificial weathering under systematically varied moisture conditions N2 - Polyether and -ester urethanes (PU) were exposed to artificial weathering at 40 °C and artificial UV radiation in a weathering chamber. In 3 parallel exposures, humidity was varied between dry, humid, and wet conditions. Material alteration was investigated by various analytical techniques like size exclusion chromatography (SEC), liquid chromatography-infrared spectroscopy (LC-FTIR), thermal-desorption gas chromatography-mass spectrometry (TD-GC-MS), fluorescence mapping and dynamic mechanical analysis (DMA). Our results show that depending on the weathering conditions, different degradation effects can be observed. By means of SEC an initial strong decrease of the molar masses and a broadening of the mass distributions was found. After a material dependent time span this was followed by a plateau where molar mass changes were less significant. A minor moisture-dependent degradation effect was only found for polyester PU. Fluorescence measurements on two materials revealed an increase in the luminescence intensity upon weathering process reaching a saturation level after about 500 h. The changes in the optical properties observed after different exposure conditions and times were very similar. The TD-GC-MS data showed the fate of the stabilizers and antioxidant in the course of weathering. LC-FTIR measurements revealed a change in peak intensities and the ratio of urethane and carbonyl bands. KW - Polyurethane KW - Artificial weathering KW - Moisture KW - Crosslinking KW - Degradation PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0142941819303708 U6 - https://doi.org/10.1016/j.polymertesting.2019.105996 SN - 0142-9418 VL - 78 SP - 105996, 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-48625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Epping, Ruben T1 - Microstructure characterization of oligomers by analysis of UPLC / ESI-TOF-MS reconstructed ion chromatograms N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. Small, often isobaric heterogeneities in topology or microstructure can usually not be simply separated chromatographically or distinguished by any common detector. Nowadays a wide range of different analytical separation techniques and multi-detection possibilities are available. The challenge consists in a clever combination of these techniques with a specific approach of data analysis. In this presentation different liquid chromatographic separation modes were combined with Electrospray Time-of-Flight mass spectrometry. The online coupling allows the analysis of reconstructed ion chromatograms (RIC) of each degree of polymerization. While a complete separation often cannot be achieved, the derived retention times and peak widths lead to information on the existence and dispersity of heterogeneities in microstructure or topology, that are otherwise inaccessible This method is suitable to detect small differences in e. g. branching, topology, monomer sequence or tacticity and could potentially be used in production control of oligomeric products or other routinely done analyses to quickly indicate deviations from set parameters. Based on a variety of examples e.g. the topology elucidation of branched EO-PO copolymers, the possibilities and limitations of this approach were demonstrated. T2 - Analyticon 2020 CY - Online meeting DA - 05.11.2020 KW - Microstructure KW - Copolymer KW - LC-MS PY - 2020 AN - OPUS4-51540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Epping, Ruben T1 - View into the Depths of Copolymer Microstructure N2 - For different kinds of polymers it will be shown how it could be realized to obtain information on small, sometimes isomeric topological heterogeneities by coupling UPLC / ESI-TOF-MS and LC /MALDI-TOF-MS. T2 - DSM, Fall Meeting CY - Breda, The Netherlands DA - 07.11.2019 KW - Microstructure KW - LC-MS KW - Copolymer PY - 2019 AN - OPUS4-49587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Copolymer structure elucidation by multidimensional techniques with focus on UPLC x ESI-TOF-MS N2 - Structure elucidation of complex synthetic copolymers still represents a challenge. An one-dimensional separation technique cannot give the answer to the question: What are the molar mass distribution (MMD), the functionality distribution (FTD), the chemical composition distribution (CCD), the monomer sequence distribution (MSD), the topology differences within a single broad distributed polymer sample? Since the first LC/ ESI-MS experiment of the Nobel prize winner John B. Fenn in 1984, the coupling of liquid chromatographic to mass spectrometric techniques gained a continuous rapid development. Often the deficiencies of stand-alone methods can be bridged. LC, blind to structural information needs mass spectrometry as one of the most powerful detectors able to give detailed information on e.g. the repeat units, functionalization or copolymer composition of the chromatographic separated constituents. A separation prior to MS reduces radical the dispersity which is one of the reasons for failing of MS. Also problems with different ionization probabilities in complex mixtures can partly be overcame. Different LC separation techniques as size exclusion chromatography (SEC), liquid adsorption chromatography (LAC), liquid chromatography at critical conditions (LCCC) and gradient elution liquid chromatography (GELC) combined with Matrix assisted Laser Desorption Ionization (MALDI) respectively Electrospray Ionization (ESI) Time of Flight (TOF) mass spectrometry are able to give information which otherwise are completely inaccessible. In some cases CID tandem mass spectrometry is applied. Fragmentation of suitable precursor ions resulted in typical fragment ion patterns. This technique enables an additional information on e.g. sequences, structural defects and topology of complex polymer mixtures. Herein a new approach is demonstrated to provide evidence of different functionalities and short block sequences in statistical EO-PO copolymers. Furthermore silsesquioxane mixtures and Polyglycerols are investigated concerning occurring topology effects. T2 - 253rd ACS National Meeting CY - San Francisco, CA, USA DA - 02.04.2017 KW - Copolymer KW - Microstructure KW - Liquid chromatography KW - Mass spectrometry PY - 2017 AN - OPUS4-43372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epping, Ruben A1 - Panne, Ulrich A1 - Falkenhagen, Jana T1 - Critical conditions for liquid chromatography of statistical copolymers: Functionality type and composition distribution characterization by UP-LCCC/ESI-MS N2 - Statistical ethylene oxide (EO) and propylene oxide (PO) copolymers of different monomer compositions and different average molar masses additionally containing two kinds of end groups (FTD) were investigated by ultra high pressure liquid chromatography under critical conditions (UP-LCCC) combined with electrospray ionization time-of flight mass spectrometry (ESI-TOFMS). Theoretical predictions of the existence of a critical adsorption point (CPA) for statistical copolymers with a given chemical and sequence distribution1 could be studied and confirmed. A fundamentally new approach to determine these critical conditions in a copolymer, alongside the inevitable chemical composition distribution (CCD), with mass spectrometric detection, is described. The shift of the critical eluent composition with the monomer composition of the polymers was determined. Due to the broad molar mass distribution (MMD) and the presumed existence of different end group functionalities as well as monomer sequence distribution (MSD), Gradient separation only by CCD was not possible. Therefore, isocratic separation conditions at the CPA of definite CCD fractions were developed. Although the various present distributions partly superimposed the separation process, the goal of separation by end group functionality was still achieved on the basis of the additional dimension of ESI-TOF-MS. The existence of HO-H besides the desired allylO-H end group functionalities was confirmed and their amount estimated. Furthermore, indications for a MSD were found by UPLC/MS/MS measurements. This approach offers for the first time the possibility to obtain a fingerprint of a broad distributed statistical copolymer including MMD, FTD, CCD, and MSD. KW - Polymer KW - Liquid chromatography at critical conditions KW - ESI-TOF-MS PY - 2017 U6 - https://doi.org/10.1021/acs.analchem.6b04064 SN - 0003-2700 SN - 1520-6882 VL - 89 IS - 3 SP - 1778 EP - 1786 AN - OPUS4-39240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - 30 years LC-MS of synthetic macromolecules – an old story or something left to discover? N2 - Structure elucidation of complex synthetic copolymers still represents a challenge. A one-dimensional separation technique cannot give the answer to the question: What are the molar mass distribution (MMD), the functionality distribution (FTD), the chemical composition distribution (CCD), the monomer sequence distribution (MSD), the topology differences within a single broad distributed polymer sample? Is the coupling of liquid chromatographic separation techniques to mass spectrometry able to fill the gaps to a certain degree? Different LC separation techniques as size exclusion chromatography (SEC), liquid adsorption chromatography (LAC), liquid chromatography at critical conditions (LCCC) and gradient elution liquid chromatography (GELC) combined with Matrix assisted Laser Desorption Ionization (MALDI) respectively Electrospray Ionization (ESI) Time of Flight (TOF) mass spectrometry are able to give information which otherwise are completely inaccessible. In some cases, CID tandem mass spectrometry is applied. Fragmentation of suitable precursor ions resulted in typical fragment ion patterns. This technique enables an additional information on e.g. sequences, structural defects and topology of complex polymer mixtures. Often the deficiencies of stand-alone methods can be bridged. LC, blind to structural information needs mass spectrometry as one of the most powerful detectors able to give detailed information on e.g. the repeat units, functionalization or copolymer composition of the chromatographic separated constituents. A separation prior to MS reduces radical the dispersity which is one of the reasons for failing of MS. Also problems with different ionization probabilities in complex mixtures can partly be overcame. The lecture will provide a series of examples where LC-MS has been applied to evaluate complex macromolecules and mixtures of these. On- and offline coupling principles will be compared and the pros and cons of both mass spectrometric techniques will be discussed. T2 - SCM-8; International Symposium on the CY - Amsterdam, The Netherlands DA - 30.01.2017 KW - Characterization of polymers KW - HPLC KW - UPLC/ESI-TOF-MS KW - LC/MALDI-TOF-MS KW - Coupling techniques PY - 2017 AN - OPUS4-39276 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Kang, Nianjun A1 - Wang, De-Yi A1 - Falkenhagen, Jana A1 - Thünemann, Andreas A1 - Schönhals, Andreas T1 - Structure–Property Relationships of Nanocomposites Based on Polylactide and Layered Double Hydroxides – Comparison of MgAl and NiAl LDH as Nanofiller N2 - Nanocomposites based on poly(L-lactide) (PLA) and organically modified Ni/Al layered double hydroxides (NiAl/LDHs) are prepared by melt blending and investigated by a combination of size exclusion chromatography, differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering, and broadband dielectric spectroscopy. A detailed comparison to the behavior of the corresponding MgAl/LDH–PLA nanocomposites is made. SAXS investigations show that the morphology of the NiAl/LDH–PLA nanocomposites is more intercalated compared to the MgAl/LDH based PLA nanocomposite, which is more exfoliated. The DSC investigation gives a different dependence of the degree of crystallization on the concentration of LDH for NiAl/LDH–PLA than for MgAl/LDH–PLA nanocomposite system. These differences are discussed taking the differences of the morphologies of both systems into account. Broadband dielectric spectroscopy reveals information about the molecular dynamics where essential differences are observed for all relaxation processes taking place in both systems which were related to the different morphologies. KW - Nanocomposites KW - Polylactide PY - 2017 U6 - https://doi.org/10.1002/macp.201700232 SN - 1022-1352 SN - 1521-3935 VL - 218 IS - 20 SP - Article 1700232, 1 EP - 12 PB - Wiley-VCH Verlag AN - OPUS4-42597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Elert, Anna Maria A1 - Becker, Roland A1 - Dümichen, Erik A1 - Eisentraut, Paul A1 - Falkenhagen, Jana A1 - Sturm, Heinz A1 - Braun, Ulrike T1 - Comparison of different methods for MP detection: What can we learn from them, and why asking the right question before measurments matters? N2 - In recent years, an increasing trend towards investigating and monitoring the contamination of the environment by microplastics (MP) (plastic pieces < 5 mm) has been observed worldwide. Nonetheless, a reliable methodology that would facilitate and automate the monitoring of MP is still lacking. With the goal of selecting practical and standardized methods, and considering the challenges in microplastics detection, we present here a critical evaluation of two vibrational spectroscopies, Raman and Fourier transform infrared (FTIR) spectroscopy, and two extraction methods: thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) and liquid extraction with subsequent size exclusion chromatography (SEC) using a soil with known contents of PE, PP, PS and PET as reference material. The obtained results were compared in terms of measurement time, technique handling, detection limits and requirements for sample preparation. The results showed that in designing and selecting the right methodology, the scientific question that determines what needs to be understood is significant, and should be considered carefully prior to analysis. Depending on whether the object of interest is quantification of the MP particles in the sample, or merely a quick estimate of sample contamination with plastics, the appropriate method must be selected. To obtain overall information about MP in environmental samples, the combination of several parallel approaches should be considered. KW - Microplastics KW - FTIR imaging KW - Raman imaging KW - TED-GC-MS KW - SEC KW - Analysis and identification PY - 2017 U6 - https://doi.org/10.1016/j.envpol.2017.08.074 SN - 0269-7491 SN - 1873-6424 VL - 231 IS - 2 SP - 1256 EP - 1264 PB - Elsevier AN - OPUS4-42157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Epping, Ruben T1 - View into the depths of copolymer microstructure by a special approach of LC-MS data evaluation N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. This is and will remain a challenge for analysts. First a very short overview will be given concerning the common liquid separation techniques for polymers (SEC, LAC, LCCC, GELC) coupled to soft ionization mass spectrometric methods like MALDI and ESI-MS with focus on their limitations. For very broadly distributed samples or chemical very similar species the superposition of different separation mechanisms in chromatography is unavoidable or the separation efficiency cannot be optimized. Different ionization probabilities and species of the same nominal mass with completely different structures are just two problems of mass spec of complex polymer mixtures. Subsequently, different examples will be shown how these limitations in some cases could be outsmarted. First example will be the separation of statistical EO-PO copolymers of different chemical compositions by end group functionality and the quantification of end group fractions over the whole CCD. Here an UP-LCCC / ESI-TOF-MS coupling is applied. Further for different kinds of polymers it will be shown how it could be realized to obtain information on small isobaric/isomeric topological heterogeneities by coupling UP-SEC / ESI-TOF-MS. All results are based on the data processing of reconstructed ion chromatograms of single mass traces of complex ESI-MS spectra. T2 - SCM-9 CY - Amsterdam, The Netherlands DA - 29.01.2019 KW - Reconstructed ion chromatograms KW - Copolymer KW - Microstructure KW - LC x ESI-TOF-MS PY - 2019 AN - OPUS4-47836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Biobased and biogegradable polymers: Analytical challenges N2 - The variability and heterogeneity in their structural composition is significant for nearly all synthetic and natural polymers. Beside molar mass also functionality type distribution, copolymer composition distribution and architectural features are responsible for changing the material properties. A wide range of analytical techniques are available to get insight into these parameters. However, in most cases it is essential to combine different sophisticated techniques to get closer to actual structures and to avoid statistical averages. Different liquid chromatographic separation modes and their coupling in a two-dimensional way (SEC, LCCC, HILIC, 2D-LC) in combination with suitable detection techniques (e.g. UV, RI, LS, IR, MALDI/ESI-MS) as well as techniques like BET, DCS, SEM/TEM were applied to make structural features visible. A few aspects are discussed for structural different polylactides from various synthesis routes and their behavior in LC-MS. Moreover, some analytical results for technical lignins valorized by mechanochemical treatment or modified by functional polymers are presented. T2 - 10th Intern. Symp. on the Separation and Characterisation of Natural and Synthetic Macromolecules (SCM-10) CY - Amsterdam, Netherlands DA - 01.02.2023 KW - Poly(lactides) KW - Technical lignin PY - 2023 AN - OPUS4-57002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fink, Friedrich A1 - Stawski, Tomasz M. A1 - Stockmann, Jörg M. A1 - Emmerling, Franziska A1 - Falkenhagen, Jana T1 - Surface Modification of Kraft Lignin by Mechanochemical Processing with Sodium Percarbonate N2 - In this article, we present a novel one-pot mechanochemical reaction for the surface activation of lignin. The process involves environmentally friendly oxidation with hydrogen peroxide, depolymerization of fractions with high molecular mass, and introduction of new carbonyl functions into the lignin backbone. Kraft lignin was ground with sodium percarbonate and sodium hydroxide in a ball mill at different time intervals. Analyses by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), size exclusion chromatography (SEC), dynamic vapor sorption (DVS), and small-angle X-ray scattering (SAXS) showed significant improvements. After only 5 min of reaction, there was a 47% reduction in mass-average molecular weight and an increase in carboxyl functionalities. Chemical activation resulted in an approximately 2.8-fold increase in water adsorption. Principal component analysis (PCA) provided further insight into the correlations between IR spectra and SAXS parameters KW - Kraft Lignin KW - Mechanochemical oxidation KW - SEC KW - FTIR KW - SAXS KW - PCA PY - 2023 U6 - https://doi.org/10.1021/acs.biomac.3c00584 SN - 1525-7797 SP - 1 EP - 11 PB - American Chemical Society AN - OPUS4-58074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Choi, Ching-Yi A1 - Lossada, F. A1 - Walter, K. A1 - Fleck-Kunde, T. A1 - Behrens, S. A1 - Meinelt, T. A1 - Falkenhagen, Jana A1 - Hiller, M. A1 - Oschkinat, H. A1 - Dallmann, A. A1 - Taden, A. A1 - Börner, H.G. T1 - Organic transformation of lignin into mussel-inspired glues: next-generation 2K adhesive for setting corals under saltwater N2 - The 2-methoxyphenol units (G-units) in lignin are modified by demethylation and oxidation to provide the activated lignin as one part of an advanced biobased two-component (2K) adhesive system, which exhibits promising shear strengths in dry and underwater applications. The activation of lignin is straightforward and generates quinones via demethylation and periodate oxidation. These act as Michael acceptors and react smoothly with multi-thiol-star polymers to yield thiol-catechol connectivities (TCCs). The mussel-inspired material platform acts as a very robust and versatile adhesive, combining low-cost and readily available lignin with multi-thiols to achieve outstanding adhesion strengths of up to 15 MPa in dry application. In particular, the 2K system is compatible with the marine biological environment and shows no acute toxicity to sensitive organisms such as fish eggs. Thus, one possible application of this material could be an adhesive for setting temperature-resistant corals in damaged reefs. KW - Lignin modification KW - Mussel-inspired adhesive systems PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-594588 SN - 1463-9270 SP - 1 EP - 15 PB - RSC CY - Cambridge AN - OPUS4-59458 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Falkenhagen, Jana A1 - Kricheldorf, H. R. T1 - Polycondensations and Cyclization of Poly(L-lactide) Ethyl Esters in the Solid State N2 - The usefulness of seven different Tin catalysts, Bismuth subsalicylate and Titan tetra(ethoxide) for the polycondensation of ethyl L-lactate (ELA) was examined at 150 °C/6 d. Dibutyltin bis(phenoxides) proved to be particularly effective. Despite the low reactivity of ELA, weight average molecular masses (Mw) up to 12 500 were found along with partial crystallization. Furthermore, polylactides (PLAs) of similar molecular masses were prepared via ELA-initiated ROPs of L-lactide by means of the four most effective polycondensation catalysts. The crystalline linear PLAs were annealed at 140 or 160 °C in the presence of these catalysts. The consequences of the transesterification reactions in the solid PLAs were studied by means of matrix-assisted laser desorption/ionization (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC) and small-angle X-ray scattering (SAXS). The results indicate that polycondensation and formation of cycles proceed in the solid state via formation of loops on the surface of the crystallites. In summary, five different transesterification reactions are required to explain all results. KW - Polylactide KW - MALDI-TOF MS KW - Crystalinity PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-592934 SN - 1759-9962 VL - 15 IS - 2 SP - 71 EP - 82 PB - RSC Publ. CY - Cambridge AN - OPUS4-59293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -