Spectral fluctuation in SERS spectra of benzodiazepin molecules: The case of oxazepam

Abstract

The surface‐enhanced Raman spectroscopy (SERS) spectra of a benzodiazepine molecule, oxazepam, have been recorded using a nanoporous silica matrix containing gold nanoparticles as SERS substrate. In the measured spectra, we clearly observe spectral fluctuations, with slight shifts in wavenumber, appearance, and disappearance of peaks and variations in the shape of some peaks. By comparison with spectra simulated by density functional theory, we attribute those fluctuations to the experimental signature of various adsorption sites of the molecule on the gold surface. The effect of temperature and laser power was also studied, suggesting that changes in absorption sites can be optically activated. Such features could cause misinterpretation of SERS spectra and errors in the identification of drugs. We suggest that they should be systematically considered for the correct interpretation of SERS spectra of drug molecules.

An experimental guide to in operando electrochemical Raman spectroscopy

“…Besides choosing the laser intensity as low as possible, these issues can, if necessary, be addressed by varying the illuminated surface area frequently and choosing a flow reactor for a constant exchange of analytes. It is also recommended to reduce the laser intensity in order to avoid temperature-dependent fluctuations [72]. Additionally, the laser can introduce fluorescence, leading to an increased background signal [25].…”

Raman spectra and DFT calculations of thiophenol molecules adsorbed on a gold surface

“…Since its discovery at the end of the 70s, SERS is considered as an extremely promising analytical method for the detection of low concentration chemical species. Its application covers a very broad field: the detection of drugs or illegal substances, 1 the analysis of pollutant molecules in water, [2][3][4] the identification of chemical species at the surface of metals, 5 the study of pigments in art or archeology, 6,7 and many others.…”