A multifunctional Ag@AuNFs/PB/SPE substrate for sensitive ratiometric EC-SERS detection of carbendazim.

Surface-enhanced Raman scattering (SERS) is a promising alternative for trace analysis, but its potential is largely limited by weak target-substrate affinity, complex matrix interference, and signal fluctuations. This study develops a ratiometric electrochemical (EC)-SERS platform for carbendazim (CBZ) detection and fabricates a silver@gold nanoflowers/prussian blue/screen-printed electrode (Ag@AuNFs/PB/SPE) substrate. Leveraging the multifunctionality of Ag@AuNFs/PB/SPE, the EC-SERS platform realizes electro-enhanced adsorption and self-calibrating detection of CBZ. Both experiments and theoretical simulations show that an applied potential of -0.6 V significantly boosts van der Waals (vdW) forces between CBZ and Ag nanoparticles, promoting efficient CBZ enrichment at "hot spots". Compared to conventional ratiometric SERS methods, this optimal potential boosts the CBZ SERS signal by 3.8-fold. Correspondingly, the low detection limit of the ratiometric EC-SERS platform is 3.7 nM, representing a 9.3-fold improvement in sensitivity over ratiometric SERS (34.5 nM). Thus, multifunctional Ag@AuNFs/PB/SPE substrates have promoted the development of SERS technology for practical application scenarios.