Polyelectrolytes as new matrices for secondary ion mass spectrometry
Significant enhancements in ion yields in time-of-flight secondary ion mass spectrometry (TOF-SIMS) are observed when water-soluble analytes are mixed with a polyelectrolyte, e.g., poly(diallyldimethylammonium chloride) or poly(sodium 4-styrenesulfonate), and then deposited in the layer-by-layer method on a surface. This previously unobserved effect is demonstrated for 5-chloro-8-methoxyquinoline appended diaza-18-crown-6, 5-(2-aminoethoxy)methyl-5-chloro-8-methoxyquinoline appended diaza-18-crown-6, acridine, 9-anthracenecarboxylic acid, and ferrocenecarboxylic acid. By optical ellipsometry film thicknesses range from ca. 5–20 Å. X-ray photoelectron spectroscopy shows significantly less analyte in the polyelectrolyte-analyte films than in the neat analytes. However, TOF-SIMS generally shows significant enhancements in ion yields from the polyelectrolyte films compared with either the neat compounds or the compounds solubilized with acid or base and then dried on a surface. These significant enhancements in ion yields also appear to extend to analyte fragments and cationized molecular species. Some enhancement is also observed for dried droplets of analytes mixed with a polyelectrolyte on surfaces.
KeywordsHeterolysis Diallyldimethylammonium Chloride Ferrocenecarboxylic Acid Polyelectrolyte Film Thin Native Oxide
- 1.TOF-SIMS, Surface Analysis by Mass Spectrometry; Vickerman, J. C.; Briggs, D., Eds.; IM Publications: Chichester, UK, 2001; pp 753–778.Google Scholar
- 2.Hagenhoff, B. Optimization Methods: Cationization. In TOF-SIMS, Surface Analysis by Mass Spectrometry; pp Vickerman, J. C.; Briggs, D., Eds., IM Publications: Huddersfield, UK, 2001; 285–308.Google Scholar
- 5.Benninghoven, A.; Rudenauer, F. G.; Werner, H. W. Secondary Ion Mass Spectrometry; John Wiley and Sons: New York, 1987.Google Scholar
- 17.Ariga, K.; Onda, M.; Lvov, Y.; Kunitake, T. Alternate Layer-by-Layer Assembly of Organic Dyes and Proteins is Facilitated by Premixing with Linear Polyions. Chem. Lett. 1997, 25–26.Google Scholar
- 23.Moulder, J. F.; Stickle, W. F.; Sobol, P. E.; Bomben, K. D. Handbook of X-ray Photoelectron Spectroscopy; Physical Electronics, Inc: Eden Prarie, MN, 1995.Google Scholar