Banca de DEFESA: ARIANA MARIA DOS SANTOS LIMA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : ARIANA MARIA DOS SANTOS LIMA
DATA : 06/05/2021
HORA: 08:30
LOCAL: Salvador
TÍTULO:
NUTRITIONAL ASSESSMENT AND DETERMINATION OF PESTICIDES IN VEGETABLE CONSUMED IN SALVADOR CITY, BAHIA
PALAVRAS-CHAVES:
Vegetables, minerals, cooking processes, multivariate analysis, pattern recognition, unsupervised methods, minerals.
PÁGINAS: 155
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Análise de Traços e Química Ambiental
RESUMO:
In this work, two methods of determining minerals, present in chapter I and pesticides, in chapter II were developed. In addition to mineral determination, multivariate analysis techniques, addressing unsupervised methods - Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) and supervised methods - Linear Discriminant Analysis (LDA), were used. In the first chapter, two grams of mustard and chicory samples were digested in a digester block for two hours, using 3 and 4 mL, respectively, of acid and 1 mL of hydrogen peroxide, the minerals were determined using ICP OES. To validate the method, the merit parameters were obtained, the precision was between 0.2-8.8%, the LD and LQ values were considered satisfactory, and the accuracy evaluation was due to the use of the CRM NIST 1515 sheets of apple, which considering the t test and F test, in a 95% confidence interval confirms the accuracy of the method. Each sample went through different cooking processes: steam, cooked in a conventional stove and microwave, it was possible to verify the vegetables studied, showed the same pattern of loss of nutrients: raw> steam> cooked> microwave. The PCA and HCA allowed recognizing that the samples that passed through the same cooking method formed four distinct groups, indicating the similarity of the samples and the LDA allowed the clear separation of classes between the samples of each type of cooking, with rates of 100% selectivity, accuracy and without the presence of false positives or negatives. In the second chapter, an adapted method using the low temperature partition technique was developed in order to determine twenty-six pesticides by CG-MS, consisting of the extraction of a 4g sample previously macerated with a combination of atyl acetate / water (8: 1, v / v), this mixture vortexed for 10 min, centrifuged for 3 minutes at 300 rpm and taken to the freezer (-20ºC) until freezing, around 3 am. The results obtained were satisfactory with good linearity (r2: 9936-0.9994), LD ranging from 0.1-0.4 µdg L-1 and LQ ranging from 0.34-1.9 µg L-1. The inter and intra-day precision were within the reference parameters, between 6.3-23.4% and 2.7-18.3%, respectively. To verify the accuracy, recovery tests at three levels of fortification were performed and all results were greater than a 70% recovery. All data indicate that the method is robust, accurate and reliable. Of the twenty-five pesticides studied, three showed concentrations below the detection limit and thirteen were not detected, indicating the absence of these substances in the samples.
MEMBROS DA BANCA:
Presidente - 268481 - SERGIO LUIS COSTA FERREIRA
Interno(a) - 286034 - ANA MARIA PINTO DOS SANTOS
Interno(a) - 3204824 - JOAO BATISTA PEREIRA JUNIOR
Interno(a) - 1303987 - MARIA ELISABETE MACHADO
Externo(a) ao Programa - 1553300 - ANDERSON SANTOS SOUZA
Externo(a) à Instituição - DÉBORA DE ANDRADE SANTANA - UNEB
Externo(a) à Instituição - DOUGLAS GONÇALVES DA SILVA - UESB