Activating the SERS features of screen-printed electrodes with thiocyanate for sensitive and robust EC-SERS analysis

This study presents a novel electrochemical (EC) methodology for activating the SERS features of disposable silver screen-printed electrodes (AgSPEs) using a pseudohalide as a precipitating agent to guide the assembly of a nano-filamentous silver network responsible for a strong SERS enhancement. To the best of our knowledge, the use of thiocyanate for SPEs activation for quantitative purposes has not been reported before. In order to better study this complex system, time-resolved (TR) operando spectroelectrochemical (SEC) measurements were performed by SERS and UV-Vis and correlated with SEM imaging of the electrode surface at different steps. Moreover, to significantly increase the reproducibility of the assays, a rapid EC protocol was proposed for the first time to obtain a reliable Ag/AgSCN reference electrode (RE) and a comprehensive optimization process was conducted to determine the critical parameters. Additionally, propranolol, as an emerging pharmaceutical pollutant has been selected as a model molecule to demonstrate the applicability of the method for rapid (3 minutes) quantitative analysis in the nM range from real river and tap water samples.