Detection and Characterization of pesticides by SERS spectroscopy

• Grant number: 22/06398-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2022
• End date: November 30, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Rômulo Augusto Ando
• Grantee: Ana Luiza Clivatti Yamanaka
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 16/21070-5 - Vibrational spectroscopy with spatial resolution, AP.TEM
• Associated scholarship(s): 23/16267-8 - Dark Field Spectroelectrochemistry of Metallic Nanoparticles, BE.EP.IC

Abstract

The development of pesticides was fundamental to increasing food production. However, their deliberate use on a global scale has caused several harmful effects due to the contamination of ecosystems, becoming an environmental and public health problem. In this sense, different methodologies have been developed to detect trace amounts of these compounds or their degradation products. A quite interesting strategy is the use of metallic nanoparticles that have the effect of enhancing the Raman signal, known as the SERS effect (surface-enhanced Raman scattering). In addition to potentially being able to detect concentrations in the order of ppb of the analytic, thanks to Raman enhancement factors of up to 108, the SERS technique provides a molecular signature that allows the identification of the compound, how it interacts with the metallic surface, and also its fragments in case of degradation. Although several works report the detection of pesticides in literature via SERS, there is still a significant discrepancy in the data published, since in many cases there is a degradation of the analytic. In this project, we intend to investigate by SERS spectroscopy different pesticides, with the main objective of performing a detailed vibrational spectroscopic characterization and elucidating the interaction mechanism. The main approach will be to use Ag and Au nanoparticles as SERS substrates and perform molecular modeling via DFT calculations. Furthermore, the electrochemical behavior of some selected systems will be investigated to construct sensors that are both SERS and electroactive.(AU)