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

• Type: Article in International Scientific Journal
• Date: 2010

Authors

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

Journal

Title: Sensors and Actuators, B: Chemical

Vol. 145 No. 2

Pages: 702-707

ISSN: 0925-4005

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 230 Citations

ISI Web of Science

Scopus - 249 Citations

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6