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The development of a new device based on the use of UV-vis bare optical fibers in a long optical path length configuration and the measurement of the Raman response in normal arrangement allows us to perform UV-vis and Raman spectroelectrochemistry simultaneously in a single experiment. To the best of our knowledge, this is the first time that a spectroelectrochemistry device is able to record both spectroscopic responses at the same time, which further expands the versatility of spectroelectrochemistry techniques and enables us to obtain much more high-quality information in a single experiment. Three different electrochemical systems, such as ferrocyanide, dopamine, and 3,4-ethylenedioxythiophene, have been studied to validate the cell and to demonstrate the performance of the device. Processes that take place in solution can be properly distinguished from processes that occur on the electrode surface during the electrochemical experiment, providing a whole picture of the reactions taking place at the electrode/solution interface. Therefore, this device allows us to study a larger number of complex electrochemical processes from different points of view taking into account not only the UV-vis spectral changes in the solution adjacent to the electrode but also the Raman signal at any location. Furthermore, complementary information, which could not be unambiguously extracted without considering together the two spectroscopic signals and the electrochemical response, is obtained in a novel way.

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Metal nanoparticles are systems largely employed in surface-enhanced Raman spectroscopy (SERS). In particular, gold nanoparticles are one of the best substrates used in this field. In this work, the optimal conditions for gold nanoparticles electrodeposition on single-walled carbon nanotubes electrodes have been established to obtain the best SERS response. Using this substrate and analyzing the changes of in-situ Raman spectra obtained at different potentials, we have been able to explain simultaneously the oxidation mechanism of purine bases, differentiating the oxidation intermediates, and their orientation during the different oxidation steps. Adenine orientation hardly changes during the whole oxidation; the molecule maintains a parallel configuration and only shows a slightly tilted orientation after the first oxidation step.On the other hand, guanine orientation changes completely during its oxidation.Initially, guanine is perpendicular respect to gold nanoparticles, changing its orientation after the first oxidation process when the molecule shows a slightly tilted orientation and it finishes parallel respect to the electrode surface after the second oxidation step.

UV/Vis absorption and Raman spectroelectrochemistry have been used to study silver nanoparticles (AgNPs) electrodeposition, allowing a better understanding about the metal nanoparticles (NPs) formation process and its influence on the surface-enhanced Raman scattering (SERS) effect. These techniques have provided in-situ information related to the synthesis of AgNPs by cyclic voltammetry. Using a marker, such as cyanide anion (CN -), Raman spectroscopy has allowed us to study all changes that take place on a platinum electrode surface 3 during the AgNPs electrodeposition process. Raman spectra show different SERS behavior depending on the NPs generated. UV/Vis absorption spectroelectrochemistry yields information on the changes in AgNPs plasmon band during their electrodeposition while Raman signal is highly correlated with the kind of NPs generated. The methodology used in this work demonstrates that SERS effect depends strongly on nanoparticle size and shape.