CdTe/ZnS core/shell quantum dot-based ultrasensitive PET sensor for selective detection of Hg (II) in aqueous media

In this work, we present a simple, ultrasensitive and rapid cost-effective sensing technique based on Mercaptosuccinic acid (MSA) capped CdTe/ZnS core/shell (CS) quantum dots (QD) for the detection of toxic Hg(II) in aqueous media. The present system demonstrations a remarkably low detection limit of one pico molar (pM) which is the best-reported work till date. Here, the CdTe/ZnS CS QD is synthesized by using a simple one pot aqueous method, and are characterized with the help of UV-vis, photoluminescence, XRD, TEM and FT-IR analysis. Due to the interaction between CS QDs and the heavy metal ions, the photoluminescence (PL) intensity of QDs quenches via excited state electron transfer mechanism, and is confirmed from cyclic voltammetry and zeta potential. CdTe/ZnS QDs are found to be highly selective for Hg (II) ions whereas the interference from other toxic metal ions is insignificant. The real time analysis was further carried out with drinking water and tap water solutions and the QDs show remarkably good quenching in these solutions. This is a very simple method for detection of Hg (II) ions in aqueous media and using this method, a prototype low-cost electronic equipment is further designed and fabricated. (C) 2016 Elsevier B.V. All rights reserved.