Banca de DEFESA: GISSELI SOUZA VALASQUES
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : GISSELI SOUZA VALASQUES
DATA : 06/06/2019
HORA: 08:30
LOCAL: Instituto de quimica
TÍTULO:
DEVELOPMENT OF ANALYTICAL METHODS WITH BASED ON EXTRACTION INDUCED BY BREAKDOWN OF EMULSION IN THE ELEMENTARY ANALYSIS OF PALM OIL
PALAVRAS-CHAVES:
Palm oil, ultrasonic assisted emulsification, emulsion breaking induced extraction, atomic spectrometry, metals, amethals, multivariate optimization
PÁGINAS: 140
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Instrumentação Analítica
RESUMO:
Palm oil is an oily product of great interest to the food, cosmetics and biofuel industry. The presence of metals in this matrix is related to its oxidative stability, its nutritional value, the possibilities of contamination in the various stages of production, among other factors. The work presented in this paper deals with the development of analytical methods for the determination of metals and ametals in crude palm oil samples by atomic spectrometry techniques after emulsification assisted by ultrasonic energy followed by extraction induced by emulsion breaking (EIEB) as an alternative, simple, fast and efficient to the traditional processes of decomposition. In this context, the following works were carried out: (i) development of a method for the determination of Ca, Mg, Mn, Fe and Zn in oil crude palm oil by flame atomic absorption spectrometry (FAAS). The optimization of this method was done by constrained mixtures design and desirability function. The method have present limits of quantification between 0.018 and 0.19 mg L-1 and accuracy, expressed as repeatability (% RSD, N = 10) between 1.8 and 3.2% for the five metals studied. The accuracy of the method was achieved by applying addition/recovery tests of the analytes to the samples (obtaining recoveries between 87 and 113%) and by comparing the concentration values found by EIEB with the values found by dry decomposition, finding good agreement between these values. The application of the EIEB method in samples collected in the State of Bahia (Brazil) showed that the concentrations (mg L-1) of the samples were 3.93 to 13.9 (Ca), 0.37 to 2.26 (Mg), > LQ to 0.32 (Mn), 1.77 to 8.57 (Fe) and 0.38 to 2.54 (Zn); (ii) development of a method for the determination of As and Se in crude palm oil by atomic fluorescence spectrometry coupled to the hydrides generation (HG-AFS) and Hg by cold vapor generation (CV-AFS). Two-level fractional factorial design (25-1), Doehlert design and desirability function were used in the optimization process. The method presented limits of quantification of 0.72; 0.12 and 1.5 μg L-1 and accuracy expressed as repeatability (% RSD, N = 10, 5 μg L -1) of 1.7; 2.5 and 3.5% respectively for As, Hg and Se. The accuracy of the method was reached by addition / recovery tests (recoveries between 90 and 128%) and by comparison of the concentration values found by decomposition in Teflon® bombs, showing good agreement. The concentrations (μg L-1) of As, Hg and Se found in the samples were 1.28 to 1.58 (As) and 2.39 to 7.96 (Se). Concentrations of Hg were below LQ in the analyzed samples; (iii) development of a method for determination of Cd and Pb in crude palm oil by graphite furnace atomic absorption spectrometry (GFAAS). The method was optimized using Doehlert design and desirability function. The method have presented quantification limits of 0.16 and 0.12 μg L-1 and accuracy of 1.8 and 5.4% respectively for Cd and Pb. Accuracy was accessed by applying recovery/addition tests and values between 88.5 and 112% were obtained. Quantities of Cd and Pb respectively between 1.39 and 2.31 and 2.36 and 6.29 μg L-1 were found in the analyzed samples.
MEMBROS DA BANCA:
Presidente - 286034 - ANA MARIA PINTO DOS SANTOS
Interno - 268481 - SERGIO LUIS COSTA FERREIRA
Interno - 1303987 - MARIA ELISABETE MACHADO
Externo à Instituição - MARCOS DE ALMEIDA BEZERRA - UESB
Externo à Instituição - CLEBER GALVAO NOVAES - UESB