Banca de DEFESA: JOÃO HONORATO SANTOS NETO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JOÃO HONORATO SANTOS NETO
DATA : 15/12/2020
HORA: 09:00
LOCAL: SALA DE VIDEOCONFERÊNCIA DA PÓS GRADUAÇÃO
TÍTULO:

LOW COST INSTRUMENTATION FOR CHEMICAL ANALYSIS BASED ON DIGITAL IMAGE

PALAVRAS-CHAVES:

Digital image, Colorimetry, Iron (II) / (III) speciation, urea.

PÁGINAS: 150
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Instrumentação Analítica
RESUMO:

The works carried out in this Thesis used the innovation of the methods of chemical analysis by digital image with instruments built from accessible and low cost materials when compared to other instruments. Two devices were built to capture digital images of colorimetric reactions. In the first work (Chapter I), a webcam was used as a detector and a wooden box for external light isolation, to capture images of colorimetric reactions, using the chromogenic reagent 1,2 orthophenanthroline, in order to quantify Fe (II )  and Fe (III) in white wine samples. The method presented accuracy of 3.47% for Fe (II) and 5.36% for total Iron with Limit of Detection (LD) of 0.042 mg/L and Limit of Quantification (LQ) of 0.141 mg/L. Six wine white samples was analyzed and the concentrations found varied between 0.41 to 1.67 mg/L for Fe (II) and between 0.69 to 1.71 mg/L for total iron. In the second work (Chapter II), a digital camera microscope-type was used as a detector coupled to a system with mechanical aspiration built from polyvinyl chloride (PVC) tubes with the aim of to capture images and measure the colorimetric variation of a reaction using diacetylmonoxime (butane-2,3-dione monoxime) for determine urea in UHT liquid milk. This method was subjected to three different mathematical treatments that showed accuracy between1.58 to 5.77% with LD ranging from 0.35 to 1.77 mg/L and LQ ranging from 0.52 to 2.54 mg/L. Eight samples milk were analyzed and the urea content varied between 161.37 to 420.33 mg/L. Multivariate optimization and analytical validation processes were applied in the two methods developed. Despite the studies using instruments with simple and low-cost materials, the figures of merits as linearity and accuracy were satisfactory for the purposes of the analyzes. The concentrations found in the samples are similar to studies applied for same sample. It was concluded that simple and low cost instrumentation for digital image analysis can be an alternative for several areas where complex and costly instrumentation is the only alternative. In addition, the versatility in the construction of equipment of this nature allows the analyst to adapt them according to his needs and this characteristic is very important in view of the diversity of location daily in the scientific environment.

MEMBROS DA BANCA:
Presidente - 286034 - ANA MARIA PINTO DOS SANTOS
Interno - 659.324.555-00 - MARCOS DE ALMEIDA BEZERRA - UFF
Interno - 268481 - SERGIO LUIS COSTA FERREIRA
Interno - 670.936.635-91 - VALFREDO AZEVEDO LEMOS - UFBA
Interno - 318.201.155-34 - WALTER NEI LOPES DOS SANTOS - UFBA
Externo à Instituição - LIZ OLIVEIRA DOS SANTOS
Externo à Instituição - CLEBER GALVAO NOVAES - UESB
Externo à Instituição - FABIO ALAN CARQUEIJA AMORIM - UESC-BA
Externo à Instituição - ADRIANO DE ARAÚJO GOMES - UFRJ