SERS and in situ SERS spectroelectrochemical investigations of serotonin monolayers at a silver electrode

Surface enhanced Raman scattering (SERS) technique was used to observe the adsorption structure of serotonin (5-hydroxytryptamine, 5-HT) monolayers formed on silver electrode surface at pH 11 and also by the aid of density functional theory (DFT). The SERS spectrum implied that monolayers of 5-HT could be self-assembled on the silver surface through O10 and N6 atoms and the molecular plane should be tilted on the surface. In situ electrochemical SERS experiment was performed in 0.1 mol L−1 KCl solution to investigate the stability of the 5-HT monolayers on the silver electrode surface. It could be found that 5-HT monolayers on silver surface experienced the changes of adsorption fashions as the potential shifting to a more negative direction prior to complete detachment from the silver surface.

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► Observation of the adsorption of 5-HT monolayers on the silver surface is conducted by SERS.
► Adsorption structure of 5-HT experienced a reorientation state with the applied potential.
► DFT method is used to elucidate the normal Raman and SERS data of 5-HT.