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Título: PHOTOLUMINESCENT DETERMINATION OF AMINOGLYCOSIDES USING GRAPHENE QUANTUM DOTS IN AQUEOUS SYSTEMS CONTAINING FE(III) OR SILVER NANOPARTICLES
Autor: IGOR ARAUJO PINTO
Instituição: PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO - PUC-RIO
Colaborador(es):  RICARDO QUEIROZ AUCELIO - ADVISOR
Nº do Conteudo: 37828
Catalogação:  25/04/2019 Idioma(s):  ENGLISH - UNITED STATES
Tipo:  TEXT Subtipo:  THESIS
Natureza:  SCHOLARLY PUBLICATION
Nota:  Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
Referência [pt]:  https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=37828@1
Referência [en]:  https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=37828@2

Resumo:
Analytical probes (aqueous dispersions) of graphene quantum dots (GQDs) associated with metal ion Fe3 plus or silver nanoparticles (AgNPs) were used for the quantification of aminoglycosides antibiotics (neomycin sulfate and gentamicin sulfate) present in pharmaceutical formulations and as residues in vaccines. The indirect determination of aminoglycosides via photoluminescence measurements of GQDs (obtained from citric acid with glutathione) is relevant since under adjusted conditions analytical responses allow to monitor concentrations of the order of 10-8 mol L-1, enabling an alternative for the aminoglycosides chemical derivatization (due to the lack of chromophore groups) that rely on labor-intensive procedures (many cases difficult to reproduce) with toxic and expensive chemical agents. The determination of neomycin sulfate was proposed based on the interaction of functionalized GQDs with neomycin sulfate under mediation of different metal ions. However, most promising analytical response was obtained using Fe3 plus, which suppresses the photoluminescence of the probe after interacting with the GQDs surface, also having large affinity towards neomycin that removes Fe3 plus from the surface of GQDs, consequently, promoting restoration of the original nanomaterial photoluminescence. Such a signal restoring was proportional to the neomycin sulfate concentration added to the system (GQDs-GSH-Fe3 plus probe), the linearized response covered a three orders of magnitude (10-7 to 10-5 mol L-1), with LOD of 8.8 x 10-8 mol L-1. The proposed method was tested in the neomycin sulfate determination in pharmaceutical compositions containing neomycin sulfate and in a rubella vaccine containing trace residues of neomycin, resulting in satisfactory recoveries. The gentamicin sulfate determination was evaluated using GQDs-GSH photoluminescence response in association with AgNPs. The original GQDs-GSH photoluminescence was suppressed and a spectral shift occurred after addition of AgNPs of diameter of 20 nm. Under adjusted experimental conditions, the suppressed photoluminescence system AgNP-GQDs-GSH (probe) was restored as gentamicin sulfate concentration increased and the linearized response covered a four order of magnitude (10-8 to 10-5 mol L-1). The LOD obtained was of of 2.6 x 10-8 mol L-1. The analytical probe was used for the gentamicin determination in two veterinary pharmaceutical formulations. For the methods developed, in order to reduce the interference imposed by excipients, selectivity was achieved using solid phase extraction with a cartridge packed with a molecularly imprinted polymer (MIP) for kanamycin (template for aminoglycosides), which allowed recoveries close to 95 percent for neomycin and 97 percent for gentamicin. The proposed GQDs photoluminescence methods were also evaluated in comparison with an HPLC based method with fluorimetric detection (after chemical derivatization with OPA for neomycin and gentamicin), and the results were statistically similar. The adequate analytical performance allowed the determination of aminoglycosides using accessible reagents, and being a simple, sensitive and selective procedure.

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