Banca de DEFESA: SARA DOS SANTOS NASCIMENTO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : SARA DOS SANTOS NASCIMENTO
DATE: 07/03/2022
TIME: 14:00
LOCAL: Google Meet
TITLE:

Development of electrochemical method for determination of glyphosate based on simonkolleite and dopamine

KEY WORDS:

glyphosate, electrochemical sensor, simonkollite

PAGES: 75
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

Glyphosate (GLI) is a pesticide used around the world that has potential damage to health, its determination
involves high cost. It is important to develop low-cost methods for its determination. The objective of this work is the
development of an electrochemical sensor for GLI. GLI does not present an electrochemical signal, aiming at indirect
detection, its interaction with dopamine (DOPA) was evaluated by UV-vis spectrophotometry and electrochemical
techniques, these used a glassy carbon electrode (CV) and this one was modified with a multiwalled carbon nanotube
(CV -NTC), the best medium for analysis was evaluated (buffers: acetate pH=4.5; phosphate pH=7; borate pH=10).
Aiming at sensitivity to the system, the use of simonkolleite nanoparticles (SK) was analyzed, in addition to SK
containing Ag: 0.1% and 1%. For the development of the GLI sensor, the use of DOPA proved to be viable, proposing
a mechanism for the interaction involved. The use of CV electrode showed adsorptive mass transport, being relevant
the modification with NTC, regarding the use of different pH ranges, the use of pH=7, presented greater sensitivity,
making it the best option among the evaluated ranges. The use of SK provided greater sensitivity to the system, while
the use of SK containing Ag promoted a reduction in signal intensity, indicating that the use of SK is more interesting to
the system. The use of a CV-NTC electrode allowed the development of a sensitive method with a linear correlation
coefficient of 0.9937, detection limit of 0.1971 ppb and quantification limit of 0.6571 ppb.

BANKING MEMBERS:
Externo ao Programa - 1545506 - ANTONIO OSIMAR SOUSA DA SILVA
Interno - 1127609 - DIOGENES MENESES DOS SANTOS
Presidente - 426640 - FABIANE CAXICO DE ABREU GALDINO
Externa à Instituição - FABRICIA DA ROCHA FERREIRA - UFAL
Externo à Instituição - JOHNNATAN DUARTE DE FREITAS - IFAL
Interna - 1646575 - RUSIENE MONTEIRO DE ALMEIDA