Banca de DEFESA: LAISE APARECIDA FONSECA DINALI

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LAISE APARECIDA FONSECA DINALI
DATE: 03/03/2023
TIME: 13:30
LOCAL: On line
TITLE:

Employment of molecularly imprinted polymers with core-shell structure in miniaturized extraction techniques for determination of pesticides in food

KEY WORDS:

Pesticide. Sample preparation. MIP. Core-shell. Extraction

PAGES: 165
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The present work addresses the development of materials with a core-shell structure, selective for certain molecules. For this, molecularly imprinted polymers (MIP) were used as coating material in different types of cores. These materials were used in miniaturized extractions techniques to remove pesticide residues from food samples. Thus, three studies were carried out involving the synthesis and characterization of different materials, the optimization of sample preparation and separation methods by HPLC-UV, as well as the validation and application of the developed analytical methodologies. The first material involved the synthesis of MIP on the surface of silica nanoparticles (core@mMIP) for was used as an adsorbent in the microextraction by packed sorbent (MEPS) for the simultaneous and selective determination of three pesticides in apple juice. In the second, MIP was synthesized on a core of functionalized silver nanoparticles (Ag@MIP), and was used as an adsorbent in the pipette-tip micro-solid phase extraction (PT-μSPE) technique for the selective determination of three neonicotinoid pesticides in water of coconut. The third material consisted of a magnetic core composed of MIP-coated cobalt ferrite nanoparticles (MMIP), which was used as an adsorbent in magnetic solid-phase microextraction (MSPE) for the determination of Fluazuron in milk. All materials were subjected to different characterizations and presented the necessary conditions for application in extraction techniques, in addition to good adhesion of the polymer to the core. After optimizing several parameters that affect extraction efficiency, the preparation techniques associated with core-shell materials showed speed, low use of adsorbent, of sample and of solvent, as well as efficiency in extraction with recoveries for all pesticides studied in the range of 76.18 – 99.26%. This excellent performance is largely due to the higher binding kinetics and lower resistance to mass transfer intrinsic to the core-shell structure. The analytical methodologies developed were validated and showed satisfactory results in terms of linearity, selectivity, precision, accuracy, in addition to acceptable detection and quantification limits for all analytes. The developed methods were successfully applied in their respective real samples of processed and in natura apple juice, coconut water and cow's milk, demonstrating a high capacity to determine the analytes safely, efficiently and reproducibly.

BANKING MEMBERS:
Presidente - 1872495 - KEYLLER BASTOS BORGES
Interno - 1727278 - LUIZ GUSTAVO DE LIMA GUIMARAES
Externa ao Programa - 1954071 - MARIA CRISTINA SILVA
Externa à Instituição - RENATA PEREIRA LOPES MOREIRA - UFV
Externo à Instituição - LEANDRO AUGUSTO CALIXTO - UNIFESP