Electrodeposition of Silver Nanostructures in Ethanol for Sensitive Electrochemical SERS Detection

Surface-enhanced Raman scattering (SERS) detection and characterization upon enrichment of analyte molecules can provide an efficient means of identifying toxic species in complex matrices. We demonstrate the electrodeposition of silver nanostructures on a carbon fiber microelectrode (CFME) in an organic solvent electrolyte, addressing the need for controllable electrodeposition of silver nanoparticles on carbon fiber surfaces. It results in a plasmonic silver microelectrode (CFME-dAg) with favorable properties for electroenrichment and optical detection, without the necessity of using linker molecules to graft presynthesized silver nanostructures onto the CFME. Compared to the electrodeposition of silver nanostructures in aqueous phase, this strategy yields particles of relatively uniform size, small dimensions, and high density. The miniaturized SERS sensor platform was used for the detection of trans -β-Apo-8′-carotenal, a toxic cleavage product of β-carotene, with limits of detection in the nanomolar range. The possibility to tune the potential was applied to selectively enrich the analyte before a molecular background of a typical cellular environment of a culture medium, including proteins, amino acids, and similarly structured carotenoids.