Selective Surface-Enhanced Raman Spectroscopy Using a Polymer-Coated Substrate

The polymer, poly(vinylpyrrolidone), is investigated as a potential coating for alumina-based surface-enhanced Raman scattering (SERS) substrates. Description for dipcoating alumina substrates with a 5% (w/v) methanolic solution of the polymer is included. Using these polymercoated substrates, various compounds, including monocyclic aromatic compounds with hydroxyl, carboxyl, and various nitrogen-based functional groups, are detected. Intensity of SERS signals from the polymer-coated substrates in comparison to that of SERS signals from uncoated substrates is demonstrated to be a function of the analyte permeability to the polymer coating. Different enhancement factors are reported for various compounds, such as benzoic acid, isonicotinic acid, and 2, 4-dinitrophenol, thus indicating some enhancement selectivity of the polymer coating to various analytes. Using benzoic acid as a test compound, various coating procedures (horizontal and vertical dipping procedures) have been evaluated. The poly(vinylpyrrolidone)-coated substrate is shown to yield a relative standard deviation in SERS signal intensity of ∼20%. The potential of the polymer-coated substrate as a selective detection probe is illustrated using the analyses of binary mixtures. Finally, the advantages of the polymer coating for protecting the SERS-active layer are also discussed. © 1995, American Chemical Society. All rights reserved.

Duke Scholars

Author Tuan Vo-Dinh Biomedical Engineering