Matrix-Isolated Surface-Enhanced Raman Spectroscopy (SERS): The Role of the Supporting Matrix

The influence of a supporting matrix in surface-enhanced Raman spectroscopy (SERS) has been investigated. The support matrices were conventional TLC plates onto which Ag colloidal hydrosols mixed with the dye pararosaniline had been deposited. The protocol of preparation of the Ag sol as well as the type of TLC plate had a profound effect upon the intensity of the SERS signals of pararosaniline. The Ag sol and the TLC plate that resulted in the maximum SERS intensities yielded a detection limit of ∼ 108 femtomols (33 pg) of dye deposited onto the TLC plate. Deposition of the dye/sol mixture onto the supporting matrix also resulted in stable SERS signals for extended periods of time, in contrast to the solution-phase case, where the signal is only transient in nature. In order to obtain the SERS spectra, a remote sensing Raman spectrometer was constructed and is described.