Banca de DEFESA: LARISSA DE SÃO BERNARDO DE CARVALHO

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STUDENT : LARISSA DE SÃO BERNARDO DE CARVALHO
DATE: 04/03/2022
TIME: 08:30
LOCAL: Videoconferência
TITLE:

EVALUATION OF STRATEGIES FOR DETERMINING INORGANIC CONSTITUENTS IN INSTANT SOUPS BY PLASMA EMISSION SPECTROMETRY

KEY WORDS:

Instant soups, MIP OES, ICP OES, Extraction, Inorganic constituents

PAGES: 120
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Métodos Óticos de Análise
SUMMARY:

This work describes the evaluation of strategies for inorganic chemical determination by microwave-induced plasma optical emission spectrometry (MIP OES) and inductively coupled plasma optical emission spectrometry (ICP OES) in instant soups. In the first study, the MIP OES with N₂ plasma was evaluated for the determination of Cu, K, Mg, Mn, P and Zn in soups, after acid decomposition assisted by microwave radiation. The sample preparation procedure consisted of using a dilute nitric acid solution, 2 mol L^-1, and hydrogen peroxide. The accuracy of the method was evaluated by analyzing three certified reference materials: NIST 1515 (apple leaves), NIST 1568b (rice flour) and NIST 3234 (soy flour) and recoveries ranged from 83.3 to 107.5%. Addition and recovery tests were also carried out and the recoveries obtained ranged from 86.0 to 106.0%. The estimated detection limits for Cu, K, Mg, Mn, P and Zn were 0.09, 4.90, 1.00, 0.04, 5.40 and 0.88 mg kg^-1, respectively. The use of N₂ microwave-induced plasma proved to be a low-cost alternative for routine analysis. In another study, several strategies for the development and applicability of an extraction procedure for the determination of Ca, Cu, Fe, K, Mg, Mn, P, Sr and Zn in instant soups by ICP OES were evaluated. The investigated strategies were: use of an acid extracting solution (hydrochloric acid 8% (v v^-1) and alkaline (tetramethylammonium hydroxide (TMAH, 25% (m v^-1), cryogenic grinding of samples and use of internal standardization techniques (IS ) and standard addition (SA) compared to external calibration (EC). The instrumental plasma parameters were also optimized. The results were evaluated by the extraction efficiencies (%) of the analytes, which were below 80% for some analytes, possibly due to the different compositions of the soup samples. Therefore, further studies should be developed in order to propose a unique extraction procedure for this type of sample.

BANKING MEMBERS:
Presidente - 282814 - MARIA DAS GRACAS ANDRADE KORN
Interno - 670.936.635-91 - VALFREDO AZEVEDO LEMOS - UFBA
Interna - 2721446 - DANIELE CRISTINA MUNIZ BATISTA DOS SANTOS
Interno - 3204824 - JOAO BATISTA PEREIRA JUNIOR
Interno - 1698441 - RENNAN GEOVANNY OLIVEIRA ARAUJO
Externa à Instituição - LETÍCIA MALTA COSTA - UFMG
Externo à Instituição - DANIEL DE CASTRO LIMA - UESC-BA
Externo à Instituição - CLEBER GALVAO NOVAES - UESB
Externa à Instituição - AMALIA GEIZA GAMA PESSOA - UFPB