Banca de QUALIFICAÇÃO: JANNYELY MOREIRA NERI

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JANNYELY MOREIRA NERI
DATE: 23/09/2021
TIME: 09:00
LOCAL: VIDEOCONFERÊNCIA
TITLE:

Silver anoparticles functionalized with 2,3-dichloroquinoxaline as multiple-analyte probe (Mg²⁺, Sn²⁺ e cisteína) in aqueous medium

KEY WORDS:

quinoxaline, silver nanoparticles, cysteine, Mg², Sn²⁺, selective detection.

PAGES: 133
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Métodos Óticos de Análise
SUMMARY:

The chemistry of nitrogen-based heterocyclic compounds is extremely rich and comprehensive. Among this broad class of organic compounds, quinoxalines play an important role due their relevance to biological and technological fields, besides versatility issues associated to organic synthesis. The quinoxaline moiety is also found in many chromogenic chemosensors, which are defined as optical devices able to detect some analytes of interest, which the development of the field has attracted great attention due to simple and low-cost procedures, as well as selectivity and sensibility even in complex matrices. Recently, the employment of silver nanoparticles as probes has bring new possibilities and leading to the growth of the field. Metal cation and amino acids are relevant analytes associated to the development of selective artificial probes, especially due their ole in biological processes and environmental issues. The present manuscript describes the synthesis of silver nanoparticles (AgNPs) functionalized by 2,3-diethanolaminoquinoxaline (DEQX), via an environmentally friendly procedure. The QX-AgNPs were properly characterized by UV-Vis and ATR-FTIR spectroscopies, as well as transmission electronic microscopy (TEM), and then employed as chromogenic probes for the selective detection of L-cysteine (Cys), Mg²⁺ and Sn²⁺ in aqueous solution, even in competing medium. The QX-AgNPs were able to detect selectively Cys and Mg²⁺ in strong alkaline medium among several other amino acids and metal cations, respectively. Furthermore, the QX-AgNPs were effective to detect Sn²⁺ in pH 7.5. The selective detection of these analytes and corresponding mechanism were discussed properly based on UV-Vis FTIR and TEM analysis. The limit od detection reached 2.7 nmol L^-1, 15 nmoL L^-1 e 18 nmoL L^-1 for Cys, Mg²⁺ e Sn²⁺, respectively. The QX-AgNPS were successfully employed for the detection of Cys in urine and Mg²⁺ in tap water. Results herein reported are very representative especially when compared to other data related in literature, which confirms this work as an important advance on the field of nanoprobes for selective multi analyte detection in aqueous medium. Proposals currently under development focusing on mechanistic studies and anticancer activity of functionalized quinoxaline derivatives as well as their inclusion complexes with β-cyclodextrin are presented. Proposals currently under development are presented, focusing on mechanistic studies functionalized quinoxaline derivatives with potential anticancer activity, as well as an inclusion complex with β-cyclodextrin.

BANKING MEMBERS:
Presidente - 1803692 - FABRICIO GAVA MENEZES
Interno - 1198847 - JOSE LUIS CARDOZO FONSECA
Interna - 1569526 - RENATA MENDONÇA ARAUJO
Externa à Instituição - ANA CAROLINA DE OLIVEIRA NEVES MENEZES