Inclusion complexes for characterization and detection of pesticides by SERS spectroscopy

• Grant number: 22/06428-1
• 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: Larissa Amancio Borges Ferreira
• 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): 23/16268-4 - Scanning Near-field Optical Microscopy for the Characterization of the Localized Surface Plasmon Resonance 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. In this project, our goal is to investigate by SERS spectroscopy different pesticides of the class of organophosphates, as is the case of phosmet and methyl-parathion. The main approach is to use Ag and Au nanoparticles as SERS substrates and inclusion complexes formed by pesticides and different host molecules of the class of cucurbiturils, in order to increase selectivity and stability, and at the same time control the aggregation of nanoparticles. The development of this project will allow a fundamental study of the interaction of this kind of molecule with metallic surfaces, with the possible analytical applications for the detection of these pollutants in real samples.(AU)