Banca de DEFESA: RAINELDES AVELINO CRUZ JUNIOR

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAINELDES AVELINO CRUZ JUNIOR
DATE: 26/11/2021
TIME: 08:00
LOCAL: Instituto de Química
TITLE:

Development of analytical methods based on UV/H2O2 photo-oxidation for the determination of metals in alcoholic beverage samples using atomic absorption spectrometry with electrothermal atomization

KEY WORDS:

Sample preparation, metals, alcoholic beverages, photo-oxidation, ETAAS.

PAGES: 150
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Métodos Óticos de Análise
SUMMARY:

In this work, a complete study was developed on methodologies applied to beverage analysis, as well as presentation of a methodological proposal for sample preparation. The consumption of beverages, such as wine, around the world has been increasing significantly, as well as the sophistication of its mode of production. With this the need for sophisticated analytical methodologies for the determination of chemical species that help in the quality control, bioavailability and authenticity process of the product regarding the possible adulterations that may occur, become indispensable. The first chapter of this work focuses on bringing a descriptive qualitative bibliographic review on the most relevant works on the subject.

The second chapter presents a proposal of sample preparation method by photo oxidation using ultraviolet radiation in the process of decomposition of wine samples for pb determination. The limits of quantification and detection found were 0.89 μg L⁻¹ and 0.27 μg L^−1, respectively. The system was applied to different wine samples resulting in concentrations ranging from 2.19 to 43.48 μg L⁻¹ of lead.

The third chapter of this work proposes an online system employing 70% hydrogen peroxide (p/ p) and UV radiation for the determination of chromium in beer samples by electrothermal atomization atomic absorption spectrometry (ETAAS). The experimental factors were optimized using a complete factorial planning of two levels. The kinetic curves of degradation of the samples under different conditions were also evaluated. The apparent kinetic constant (kapp) found for the process was 0.0668 min -¹ (R² = 0.9936). The online digestion procedure allowed the determination of chromium in beer samples by ETAAS, using the external calibration technique, with analytical line 357.9 nm, in the presence of magnesium as a chemical modifier with limits of detection and quantification of 0.86 and 2.90 μg L -¹, respectively. The accuracy of the method was confirmed by the analysis of the reference material. The concentrations found ranged from 4.26 to 33.28 μg L-1.

BANKING MEMBERS:
Interno - 3204824 - JOAO BATISTA PEREIRA JUNIOR
Interno - 268481 - SERGIO LUIS COSTA FERREIRA
Interno - 318.201.155-34 - WALTER NEI LOPES DOS SANTOS - UFBA
Interna - 2721446 - DANIELE CRISTINA MUNIZ BATISTA DOS SANTOS
Externo à Instituição - GEOVANI CARDOSO BRANDÃO - UNEB
Externo à Instituição - EDWIN PALACIO
Externo à Instituição - MARIANA ANTUNES VIEIRA - UFPel