Competitive metal-ligand binding between CdTe quantum dots and EDTA for free Ca2+ determination.

Autor: Rodrigues SSM; REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal., Prieto DR; QUIANE, Department of Analytical Chemistry, Faculty of Sciences, University of Valladolid, Paseo de Belén 7, 47011 Valladolid, Spain., Ribeiro DSM; REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal. Electronic address: dsmribeiro@gmail.com., Barrado E; QUIANE, Department of Analytical Chemistry, Faculty of Sciences, University of Valladolid, Paseo de Belén 7, 47011 Valladolid, Spain., Prior JAV; REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal., Santos JLM; REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal. Electronic address: joaolms@ff.up.pt.
Jazyk: angličtina
Zdroj: Talanta [Talanta] 2015 Mar; Vol. 134, pp. 173-182. Date of Electronic Publication: 2014 Nov 13.
DOI: 10.1016/j.talanta.2014.11.008
Abstrakt: In this work, a fluorometric approach for the selective determination of calcium by using CdTe nanocrystals as chemosensors, was developed. The quantum dots interacted not with the metal, but with a ligand that also bonded the metal. The fluorescence response was modulated by the extension of the competitive metal-ligand binding, and therefore the amount of free ligand. CdTe quantum dots (QDs) with different capping layers were evaluated, as the QDs surface chemistry and capping nature affected recognition, thus the magnitude of the ensuing fluorescence quenching. The developed procedure was automated by using a multipumping flow system. Upon optimization, thioglycolic acid (TGA) and EDTA were selected as capping and ligand, respectively, providing a linear working range for calcium concentrations between 0.80-3.20 mg L(-1), and a detection limit of 0.66 mg L(-1). A quenching mechanism relying on nanocrystal destabilization upon detachment of surface Cd by the ligand was proposed.
(Copyright © 2014 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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