Hg(II) sensing based on functionalized carbon dots obtained by direct laser ablation

• Tipo: Artigo em Revista Científica Internacional
• Data: 2010

Autores

Helena Goncalves (Autor) Outra; Pedro A S Jorge (Autor) FCUP; Fernandes, JRA (Autor) Outra; Joaquim C G E Esteves da Silva (Autor) FCUP

Revista

Título: Sensors and Actuators, B: Chemical

Vol. 145 Nº 2

Páginas: 702-707

ISSN: 0925-4005

Editora: Elsevier

Indexação

ISI Web of Knowledge - 230 Citações

ISI Web of Science

Scopus - 249 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Outras ciências da engenharia e tecnologias

Outras Informações

ID Authenticus: P-003-88D

DOI: 10.1016/j.snb.2010.01.031

Abstract (EN): The synthesis of carbon nanoparticles obtained by direct laser ablation [UV pulsed laser irradiation (248 nm, KrF)] of carbon targets immersed in water is described. Laser ablation features were optimized to produce carbon nanoparticles with dimensions up to about 100 nm. After functionalization with NH2-polyethylene-glycol (PEG(200)) and N-acetyl-L-cysteine (NAC) the carbon nanoparticles become fluorescent with excitation and emission wavelengths at 340 and 450 nm, respectively. The fluorescence decay time was complex and a three-component decay time model originated a good fit (chi = 1.09) with the following lifetimes: tau(1) = 0.35 ns; tau(2) = 1.8 ns; and tau(3) = 4.39 ns. The fluorescence of the carbon dots is sensitive to pH with an apparent PKa = 4.2. The carbon dots were characterized by H-1 NMR and HSQC and the results show an interaction between PEG(200) and the carbon surface as well as a dependence of the chemical shift with the reaction time. The fluorescence intensity of the nanoparticles is quenched by the presence of Hg(II) and Cu(II) ions with a Stern-Volmer constant (pH = 6.8) of 1.3 x 10(5) and 5.6 x 10(4) M-1, respectively. As such the synthesis and application of a novel biocompatible nanosensor for measuring Hg(II) is presented.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6