Electrochemistry is a very useful technique to generate surface enhanced Raman scattering (SERS) substrates. SERS depends on two mechanisms: the electromagnetic effect, related to the plasmonic properties of the nanostructures in the substrate, and the chemical mechanism, related to the interaction between the target molecule and the substrate. Thus, Raman enhancement for a molecule strongly depends on the nature of the nanostructures that form the substrate. In this work, time-resolved Raman spectroelectrochemistry is used to generate SERS substrates, obtaining the Raman signal during the generation of the substrate, which is very useful to obtain valuable information on the Raman performance of the substrate. Two metals, Au and Ag, have been used to determine folic acid in a drug. In this example, Au SERS substrates are highly influenced by interfering compounds present in the drug tables. On the contrary, Ag SERS substrates have been demonstrated to yield very good figures of merit in the determination of folic acid in this complex sample.
