Molecularly printed electrochemical sensor using L-Lysine electropolymerization on a surface containing gold nanoparticles and reduced graphene oxide for determining levulinic acid in samples from fruit growing processing

• Grant number: 24/12002-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Nelson Ramos Stradiotto
• Grantee: Ellen da Silva Lopes
• 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

Levulinic Acid (LA), as it contains a ketone group and a carboxyl group, allows multiple possible reaction options, which makes it an excellent precursor for the most diverse materials, in addition to having antimicrobial properties and being used as an ingredient in cosmetics, additives fuel, organic syntheses, among other applications. Therefore, developing analytical methods for determining this compound is highly relevant for several areas of knowledge. In this context, the present research project aims to create an electrochemical sensor for the determination of LA, using a glassy carbon electrode (GCE) modified with reduced graphene oxide (rGO) containing a molecular imprinted polymer (MIP) formed by the monomer L -Lysine. The use of gold nanoparticles should be studied to improve the performance of the sensor to be developed. When building the sensor, microscopic (scanning electron microscopy - SEM), spectroscopic (Fourier transform infrared spectroscopy - FTIR; X-ray Photoelectron Spectroscopy - XPS) and electrochemical (Electrochemical Impedance Spectroscopy - EIS; Voltammetry) Cyclical - CV). The optimization of the sensor's performance must be carried out by evaluating the studies of the parameters of several cycles 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. Selectivity, repeatability and stability studies of the sensor will be evaluated and the developed method will be applied to determine LA in samples from fruit growing processing.