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 - 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 - 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 - 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 - 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 - 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 -