Efficient Detection of Trace Hg2+ in Water Based on the Fluorescence Quenching of Environment-friendly Thiolfunctionalized Poly(vinyl alcohol) Capped CdS Quantum Dots Nanocomposite

Abstract

9PVA and its related products are good choices for preparing environment-friendly semiconductor nanocomposites due to its wide spectral range of optical transparency, biocompatibility and biodegradability, aiming at detecting environmental samples and biology applications.10 However, the relatively weak bonding ability of hydroxy groups with metal ions has significantly affected its stable conjugation with QDs, which will cause future 2016 © The Japan Society for Analytical Chemistry † To whom correspondence should be addressed. Using environment-friendly materials for sensing toxic metal ions has drawn significant attention in recent research. Herein, we present an aqueous synthesis of stable CdS quantum dots (QDs) using thiol-functionalized poly(vinyl alcohol) (PVA) as the unique capping ligand for the detection of trace Hg 2+ in environmental water samples. The CdS QDs with an average size of 3.3 nm had good water-solubility and favorable fluorescence with a quantum yield of 32.8% and a longer luminescence lifetime of 31.9 ns. The fluorescence intensity of QDs aqueous solution in the 520 nm wavelength was quenched upon the addition of Hg 2+ . Under the optimal conditions, the ratio of the blank fluorescence intensity to the quenched fluorescence intensity was linearly proportional to the Hg 2+ concentration from 2 to 4000 nM with a detection limit of 1 nM. Also, many co-existing metal ions were not interfered with the detection of Hg 2+. This nanomaterial was successfully applied to the measurement of Hg 2+ in water samples.

Development of Technologies for Sensing Ozone in Ambient Air

“…[70][71][72][73] For this reason, we conceived the idea of using the surface statesensitivity PL of QDs for optical gas sensing. Among chemical sensor applications of photoluminescent QDs, the sensing of pH, [74][75][76][77][78] metal ions and halide ions (Mg 2+ , K + , Ca 2+ , Mn 2+ , Fe 3+ , Ni 2+ , Cu 2+ , Zn 2+ , Ag + , Hg 2+ , Pb 2+ , F -, Cland I -) 74,75,77,[79][80][81][82][83] in water by PL quenching of QDs with ion selective overlayers has been explored. The sensing of several organic and biological compounds using photoluminescent QDs has also been reported.…”

Mercury Sensing Probes

“…Guan et al used thiol-functionalized poly vinyl alcohol capped CdS quantum dots with fluorescence quenching and achieved a detection limit of 1 nM. 11 Meelapsom et al reported on a red green blue (RGB) color model with silver nanoparticles and paper microfluidic devices for selective Hg 2+ detection. 12 Firdaus et al reported on silver nanoparticles made from an aqueous fruit extract of water apple.…”

Quantum Dot-based Fluorescent Sensing

“…Guan et al reported a new method for the detection of trace Hg 2+ in water based on the fluorescence quenching of thiolfunctionalized poly(vinyl alcohol) capped CdS QDs. 4 The fluorescence intensity increased linearly with the Hg 2+ concentration over the range of 2 to 4000 nM, with a detection limit of 1 nM. Moreover, the system was resistant to interference from a number of co-existing metal ions, promising development for the detection of Hg 2+ in environmental samples.…”