Molecularly imprinted electrochemical sensor using L-Tryptophan electropolymerization on reduced graphene oxide surface with gold nanoparticles for ¿-Valerolactone determination

• Grant number: 25/00874-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Nelson Ramos Stradiotto
• Grantee: Miguel Flores Bonifacio
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated research grant: 17/22401-8 - Fruit-refinery: obtention processes, characterization methods and generation of products derived from residues of the fruitculture, AP.TEM

Abstract

¿-Valerolactone (GVL) is a compound that can be obtained from biomass from biowaste, being a key molecule in the formation of the most diverse products, being used as a biodegradable solvent, additive of sustainable fuels, chemical synthesis of high added value compounds, such as biopolymers and applied in the pharmaceutical and fragrance industries due to its organoleptic characteristics, being a compound of great commercial application. Therefore, the development of analytical methods for the determination of this compound is of the utmost relevance for several areas of knowledge. In this context, the present research project aims to develop an electrochemical sensor for the determination of GVL, using a glassy carbon electrode (GCE) modified with reduced graphene oxide (rGO) and Au nanoparticles, containing a molecular imprinted polymer (MIP) formed by the monomer L-Tryptophan (L-Trp). In the construction of the sensor, microscopic (Scanning Electron Microscopy - SEM), spectroscopic (Fourier Transform Infrared Spectroscopy - FTIR; X-ray Photoelectron Spectroscopy - XPS) and electrochemical (Electrochemical Impedance Spectroscopy - EIS; Cyclic Voltammetry - CV) characterizations will be performed. An optimization of the parameters involved in the sensor formation and analytical performance steps will be performed, the parameters in question being: number of cycles, analyte to monomer ratio, metal nanoparticle charge and pH of the electropolymerization medium, as well as the influence of extraction and reconnection time. The analytical methodology will be developed using the differential pulse voltammetry (DPV) technique, with the sensor's figures of merit being determined from the analytical curves obtained. Sensor selectivity, repeatability and stability studies will be evaluated and the developed method will be applied to determine GVL in samples from agro-industrial waste.