A novel fluorescent array for mercury (II) ion in aqueous solution with functionalized cadmium selenide nanoclusters

• Published in: Analytica chimica acta Vol. 577; no. 1; pp. 77 - 84
• Main Authors: Chen, Jinlong, Gao, YingChun, Xu, ZhiBing, Wu, GenHua, Chen, YouCun, Zhu, ChangQing
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2006; Elsevier
• Subjects: Analytical chemistry; Cadmium selenide nanoclusters; Chemistry; Exact sciences and technology; Fluorescence; Mercury (II); Spectrometric and optical methods; Fluorescence; Cadmium selenide nanoclusters; Mercury (II); Water; Phosphates; Cysteine; Nanoparticle; Replica method; Fluorescence spectrometry; Mercury ion; Atomic fluorescence spectrometry; Detection limit; Luminescence quenching; Reaction mechanism; Standard deviation; Functional group; Mercury II; Buffer solution; Colloid; Cadmium selenides; Absorption spectrometry; Fluorophore; Cold vapor; Aqueous solution; Comparative study
• ISSN: 0003-2670; 1873-4324; 1873-4324
• DOI: 10.1016/j.aca.2006.06.039

Mono-disperse CdSe nanoclusters have been prepared facilely and functionalized with l-cysteine through two steps by using safe and low cost substances. They are water-soluble and biocompatible. Especially these functionalized quantum dots can be stably soluble in water more than for 30 days, and the intensity of fluorescence and absorbance was decreased less than 15% of fresh prepared CdSe colloids. These functionalized CdSe QDs exhibited strong specific affinity for mercury (II) through QDs interface functional groups. Based on the quenching of fluorescence signals of functionalized CdSe QDs at 530 nm and no obvious wavelength shift or no new emission band in present of Hg (II) at pH 7.75 of phosphate buffer solution, a simple, rapid and specific array for Hg (II) was proposed. In comparison with conventional organic fluorophores, these nanoparticles are brighter, more stable against photobleaching, and do not suffer from blinking. Under optimum conditions, the response of linearly proportional to the concentration of Hg (II) between 0 and 2.0 × 10 −6 mol L −1, and the limit of detection is 6.0 × 10 −9 mol L −1. The relative standard deviation of six replicate measurements is 1.8% for 1.0 × 10 −7 mol L −1 Hg (II). The mechanism of reaction is also discussed. The proposed method was successfully applied for Hg (II) detection in four real samples with a satisfactory result that was obtained by cold vapor atomic fluorescence spectrometry (CV-AFS).