Schlagwörter: Dünnschichtanalyse, Massenspektrometrie, Laserdesorption, Zerstäubung Die Flugzeit-Massenspektrometrie verspricht eine wesentliche Steigerung der Empfindlichkeit der traditionellen Oberflächen-und Dünnschichtanalyseverfahren Sekundär-ionen-Massenspektrometrie (SIMS) und Sekundärneu-tralteilchen-Massenspektrometrie (SNMS). Heutige ionenoptische Konzepte und Detektorstrategien erlauben zugleich die Steigerung der Massenauflösung in einen Bereich, der bisher nur Sektorfeld-Instrumenten zugänglich war. In Verbindung mit feinfokussierten Anregungsquellen und Laser-Nachionisierungsmethoden wird dies vor allem die Möglichkeiten zur quantitativen Oberflächen-und Dünnschichtanalyse von Mikrostrukturen erweitern.Time-of-flight mass spectrometry promises a significant increase in sensivity for the traditional methods of surface and thin film analysis SIMS and SNMS. Todays ion optical concepts and detector strategies allow to increase mass resolution over that of sector field instruments. Using probes with smallfocal spots and laser-postionization, these instruments will improve quantitative surface and thin film analysis of microstructures.
The interaction between aromatic amines and ATP is based upon an electrostatic attraction of the protonated amino groups to the negatively charged phosphate groups of ATP combined with a stacking association between the ring systems. The complexes formed are relatively weak (asociation constants 4-48 M-1), shortlived (life time smaller than 0.02 s), and mainly 1:1 in stoichiometry preferring the terminal phosphate of ATP as the site of association. The divalent metal ions Mg2+ and Ca2+ bond stronger than the amines (association constants 1500 and 100 M-1, resp.) prefer the β-phosphate group changing thereby the geometry of the ATP phosphate chain. Thus, they reduce the amine-ATP association in ternary mixtures.
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