Optical Sensors based on SERS for low concentration of water contaminants

The aim of this master thesis is to fabricate and characterize Surface Enhanced Raman Scattering (SERS) probes and optimize the Raman measurements for the detection of contaminants in water in a small amount of concentration. ?? The thesis has been realized in the framework of “RaPID” project, a project funded by NATO SPS (North Atlantic Treaty Organization, divison of Science for Peace and Security). RaPID stands for Raman Probe for chemical contaminant IDentification; the goal of this project is to realize a portable device able to detect low concentrations of contaminants in water with a relatively rapid analysis in order to understand if they’re below a precise guard level imposed by law. The SERS substrates are realized on functionalized glass that is covered with gold nanoparticles to leverage the Surface Plasmon Resonance (SPR) that allows high efficiencies for the Raman spectroscopy and identification of chemical compounds. The target is to detect concentration of water contaminants (like Thiram) below the order of nM-µM. The SERS probe is also explored in a configuration including basic microfluidic channels for the input and the output of water. The experiments have been carried on in the laboratories of the Department of Applied Science and Technology of Politecnico di Torino, and at the Department of Chemistry at Universitat de Barcelona.