Síntese e caracterização de nanocubos de prata para detecção de DIURON utilizando SERS e técnica eletroquímica
Carregando...
Data
2020-07-31
Autores
Christovam, Livia Maria
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nanopartículas são estruturas que apresentam de 1 a 100 nm de dimensão e que devido às suas propriedades únicas são aplicadas em diversas áreas da pesquisa. Nanopartículas metálicas, principalmente de ouro e prata apresentam propriedades ópticas como a Ressonância Plasmon que permite utilizá-las para o sensoriamento de analitos por meio do efeito de Espectroscopia Raman Intensificada por Superfície (SERS). Esse efeito consiste em um processo em que sinais de Raman podem ser intensificados por meio da indução do campo elétrico da luz em uma nanopartícula metálica. Estudos mostram que o formato e tamanho dessas partículas influenciam suas propriedades, que no caso de nanopartículas metálicas, apresenta importância para aplicações plasmônicas. Além do efeito SERS, os métodos mais comuns de análise de compostos de interesse são os métodos eletroanalíticos que apresentam diversos pontos positivos. Dentre os possíveis analitos, o DIURON atua principalmente como herbicida no âmbito da agricultura e pode trazer malefícios para organismos vivos, principalmente do ambiente aquático. Nesse trabalho, aplicamos nanopartículas de prata em formato de cubos para a detecção de DIURON em duas maneiras: 1) SERS: sobre um substrato polimérico e utilizando a Espectroscopia Raman; 2) Voltametria cíclica: por meio da modificação de eletrodo de carbono vítreo com quitosana/nanocubos de prata e polidopamina/nanaocubos de prata. Foi possível observar o efeito SERS para a detecção do DIURON em uma concentração de 1.10-3 mol.L-1 no substrato construído. Já na parte eletroquímica, a modificação com quitosana/nanocubos de prata permitiu um aumento de 46% da área eletroativa do eletrodo. Já a modificação com polidopamina/nanocubos de prata foi aplicada para a detecção do DIURON, e em pH 3 apresentou uma queda na corrente de pico do analito, enquanto para pH 9 demonstrou um ganho de 59% do sinal analítico.
Nanoparticles are structures that range from 1 to 100 nm in size and that due to their unique properties are applied in several research areas. Metallic nanoparticles, mainly gold and silver, have optical properties such as Plasmon Resonance that allows the use of them for the sensing of analytes through the effect of Surface Enhanced Raman Spectroscopy (SERS). This effect consists of a process in which Raman signals can be intensified by inducing the electric field of light in a metallic nanoparticle. Studies show that the shape and size of these particles influence their properties, which in the case of metallic nanoparticles, is important for plasmonic applications. In addition to the SERS effect, the most common methods of analyzing compounds of interest are electroanalytical methods that have several positive points. Among the possible analytes, DIURON acts mainly as herbicide in agriculture and can cause harm to organisms, mainly in the aquatic environment. In this work, we applied silver nanoparticles in the form of cubes to detect DIURON in two ways: 1) SERS: on a polymeric substrate and using a Raman Spectroscopy; 2) Cyclic voltammetry: by modifying the glassy carbon electrode with chitosan/Ag nanoparticles and polydopamine/Ag nanoparticles. It was possible to observe the SERS effect for the detection of DIURON at a concentration of 1.10-3 mol.L-1 on substrate. In the electrochemical area, the modification with chitosan/Ag nanoparticles showed an increase of 46% in the electroactive area of the electrode. The modification with polydopamine/Ag nanoparticles was applied for the detection of DIURON, and at pH 3 there was a drop in the peak current of the analyte, while for pH 9, a gain of 59% of the analytical signal.
Nanoparticles are structures that range from 1 to 100 nm in size and that due to their unique properties are applied in several research areas. Metallic nanoparticles, mainly gold and silver, have optical properties such as Plasmon Resonance that allows the use of them for the sensing of analytes through the effect of Surface Enhanced Raman Spectroscopy (SERS). This effect consists of a process in which Raman signals can be intensified by inducing the electric field of light in a metallic nanoparticle. Studies show that the shape and size of these particles influence their properties, which in the case of metallic nanoparticles, is important for plasmonic applications. In addition to the SERS effect, the most common methods of analyzing compounds of interest are electroanalytical methods that have several positive points. Among the possible analytes, DIURON acts mainly as herbicide in agriculture and can cause harm to organisms, mainly in the aquatic environment. In this work, we applied silver nanoparticles in the form of cubes to detect DIURON in two ways: 1) SERS: on a polymeric substrate and using a Raman Spectroscopy; 2) Cyclic voltammetry: by modifying the glassy carbon electrode with chitosan/Ag nanoparticles and polydopamine/Ag nanoparticles. It was possible to observe the SERS effect for the detection of DIURON at a concentration of 1.10-3 mol.L-1 on substrate. In the electrochemical area, the modification with chitosan/Ag nanoparticles showed an increase of 46% in the electroactive area of the electrode. The modification with polydopamine/Ag nanoparticles was applied for the detection of DIURON, and at pH 3 there was a drop in the peak current of the analyte, while for pH 9, a gain of 59% of the analytical signal.
Descrição
Palavras-chave
Nanopartículas, SERS, DIURON, Nanocubos de prata