Banca de DEFESA: MADSON MOREIRA NASCIMENTO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : MADSON MOREIRA NASCIMENTO
DATA : 26/04/2021
HORA: 09:00
LOCAL: Instituto de Química
TÍTULO:

Determination of persistent organic pollutants in water samples by dispersive micro-solid extraction followed by gas chromatography and mass spectrometry

PALAVRAS-CHAVES:

Organic contaminants, Miniaturized systems, Pesticides, Polyaromatic compounds, Aquatic systems, Chemometry

PÁGINAS: 235
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Análise de Traços e Química Ambiental
RESUMO:

In this work, it was developed analytical procedures for extraction/preconcentration of organic pollutants in water samples based on dispersive micro-solid phase extraction technique. For this purpose, new and effective devices were designed to perform extraction and micro-desorption steps. In the first developed procedure, the devices were employed in the extraction/preconcentration of polycyclic aromatic hydrocarbons from fresh and marine waters. The experimental conditions were optimized and the extraction parameters were set as 100 mg of C₁₈, extraction by 32 min, and micro-desorption of 20 min with 500 µL of n-hexane. After validation, the analytical procedure provided limit of detection values ranging from 0.8 ng L^-1 (Phenanthrene) a 1.70 µg L^-1 (9,10-Phenanthrenequinone) and relative recoveries ranging from 59.1 % a 124 % (1-Methyl-6-Nitronaphthalene). The enrichment factor ranged from 39 (1,4-Naphthoquinone) to 400 (fluorene). The procedure was successfully applied in the determination of PACs in fresh and marine waters. In the second developed procedure, the extraction and micro-desorption devices were employed in the extraction of pesticide residues from fresh and marine waters. The procedure was optimized through experimental design techniques and the optimal extraction conditions were: 30 min of extraction time, 6.74 % of NaCl added into 100 mL of the water sample, and 24 min of micro-desorption with 500 µL of ethyl acetate. The detection limits ranged from 0.51 ng L^-1 (4,4-DDE) a 22.4 ng L^-1 (dimethoate), and relative recoveries ranged from 74.2 % (endrin) to 123 % (molinate). In addition, it was obtained enrichment factor ranging from 72,5 (dimetoate) to 200 (tebuconazole). The analytical procedure was applied in the extraction of pesticide residues in fresh and marine waters. Pesticides such as malathion, dimethoate, and lambda-cyhalothrin, which are commonly applied in Brazil, were detected in concentrations ranging from <LD to 120 ng L^-1 (dimethoate). The third procedure consisted of the development of a Three Ways Device for Filtration and Solid-Liquid Microextraction. The prototype of a 3D imprinted device was tested on the extraction of polycyclic aromatic hydrocarbons in water samples.

MEMBROS DA BANCA:
Presidente - 1553299 - GISELE OLIMPIO DA ROCHA
Interno(a) - 285528 - VANIA PALMEIRA CAMPOS
Interno(a) - 1649202 - LEONARDO SENA GOMES TEIXEIRA
Interno(a) - 1303987 - MARIA ELISABETE MACHADO
Interno(a) - 268481 - SERGIO LUIS COSTA FERREIRA
Interno(a) - 670.936.635-91 - VALFREDO AZEVEDO LEMOS - UFBA
Externo(a) à Instituição - JAILSON BITTENCOURT DE ANDRADE - Senai
Externo(a) à Instituição - RAILDO MOTA DE JESUS - UESC-BA
Externo(a) à Instituição - MARCO TADEU GRASSI - UFPR
Externo(a) à Instituição - EMANUEL CARRILHO