Dynamic SPME–SERS Induced by Electric Field: Toward In Situ Monitoring of Pharmaceuticals and Personal Care Products

The core of the surface-enhanced Raman spectroscopy (SERS)-based techniques for dynamic monitoring is to realize rapid and reversible adsorption. Herein, the integration technology of electro-enhanced adsorption, solid-phase microextraction, and surface-enhanced Raman spectroscopy (EE–SPME–SERS) was developed to obtain sensitive, ultrafast, and reversible SERS response toward in situ monitoring of pharmaceuticals and personal care products (PPCPs). In the EE–SPME–SERS method, a roughened Ag fiber with Au modification (r-Ag/Au fiber) was used as the SERS substrate, SPME sorbent, and working electrode. The r-Ag/Au fiber displayed good SERS sensitivity, ultrahigh photostability, and adsorption properties. The adsorption efficiency of benzidine was 76 times accelerated in EE–SPME–SERS compared to that in static adsorption. The whole process of “sampling and detection” in EE–SPME–SERS can be finished within 1 s. Reversible adsorption and desorption can be achieved in situ by switching the direction of electric field, and the regeneration process takes only a few minutes. Simulated release of benzidine from household wastewater was in situ and dynamically monitored using this strategy. EE–SPME–SERS was proved universal for ionized PPCPs and can detect multicomponents simultaneously. In addition, EE–SPME–SERS showed very good analytical properties. Great potential of EE–SPME–SERS can be expected in environmental monitoring.