A DFT study on the adsorption of a series of phosphonic acids (PAs) on the TiO2 anatase (101) and (001) surfaces was performed. The adsorption energies and geometries of the most stable binding modes were compared to literature data and the effect of the inclusion of dispersion forces in the energy calculations was gauged. As the (101) surface is the most exposed surface of TiO2 anatase, the calculated chemical shifts and vibrational frequencies of PAs adsorbed on this surface were compared to experimental 31 P and 17 O NMR and IR data in order to assign the two possible binding modes (mono-and bidentate) to peaks and bands in these spectra; due to the corrugated nature of anatase (101) tridentate binding is not possible on this surface. Analysis of the calculated and experimental 31 P chemical shifts indicates that both monodentate and bidentate binding modes are present. For the reactive (001) surface, the results of the calculations indicate that both bi-and tridentate binding modes are possible. Due to the particular sensitivity of 17 O chemical shifts to hydrogen bonding and solvent effects, the model used is insufficient to assign these spectra at present. Comparison of calculated and experimental IR spectra leads to the conclusion that IR spectroscopy is not suitable for the characterization of the different binding modes of the adsorption complexes.
The characterization of biotherapeutics represents a major analytical challenge. This review discusses the current state‐of‐the‐art in analytical technologies to profile biopharma products under native conditions, i.e., the protein three dimensional conformation is maintained during liquid chromatographic analysis. Native liquid‐chromatographic modes that are discussed include aqueous size‐exclusion chromatography, hydrophobic interaction chromatography, and ion‐exchange chromatography. Infusion conditions and the possibilities and limitations to hyphenate native liquid chromatography to mass spectrometry are discussed. Furthermore, the applicability of native liquid‐chromatography methods and intact mass spectrometry analysis for the characterization of monoclonal antibodies and antibody–drug conjugates is discussed.
In view of searching for efficient solid catalysts to be used in environmentally friendly reaction conditions, novel gel-type cross-linked polystyrenes functionalized with diethylamine and 1,5,7-triazabicyclo[4.4.0]dec-5-ene, have been prepared.
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