Optimized one‐pot synthesis of CdSe quantum dot capped with 3‐mercaptopropionic acid as an efficient fluorescent probe for selective detection of Hg (II)

Abstract

Here, we demonstrated the use of 3‐mercaptopropionic acid‐capped CdSe quantum dots (CdSe QDs) for the sensing of mercury ions (Hg2+) in solution. The size and the shape of the synthesized QD were observed through transmission electron microscopy (TEM), and crystallinity was confirmed through X‐ray diffraction (XRD) analysis. The synthesized QD showed to have mean size 4 nm. Our QD was found to sense Hg2+ ions with a detection limit of 5 ppm at pH 7.0 and a linearity range of 5–50 ppm. The effect of pH on the optical property of QD was also investigated and found that the sensor worked best at pH 7.0 with high linearity and sensitivity, thus reducing the cost of the process. The sensing mechanism of CdSe QD was further analysed through Fourier transform infrared (FTIR) spectroscopy. Therefore, our synthesized CdSe QD capped with 3‐mercaptopropionic acid demonstrated to act as an efficient nanomaterial for rapid and easy to perform sensing of mercury ion in aquatic environment.

Recent advances in II–VI group semiconductor- and carbon-based quantum dots for fluorescence-based sensing of metal ions in water

“…To modify the thiol capped-QDs according to the specific target, the free carboxyl site associated with the encapsulating layer of QDs are mostly coupled with amine-containing molecules (amino acids, peptides, etc.). Thioglycolic acid (TGA), 51 glutathione (GSH), L-cysteine (Cys), 52 and mercaptopropionic acid (MPA) 15,53 are the commonly used coatings among the thiols for the direct preparation of thiol-capped QDs. 54 Wang et al 55 showed a simple approach for sensing As 3+ using GSH-capped CdTe QDs.…”

“…). Thioglycolic acid (TGA), 51 glutathione (GSH), l -cysteine (Cys), 52 and mercaptopropionic acid (MPA) 15,53 are the commonly used coatings among the thiols for the direct preparation of thiol-capped QDs. 54 Wang et al 55 showed a simple approach for sensing As 3+ using GSH-capped CdTe QDs.…”

“…11,12 The main reason for their unique size-dependent optical and electronic properties is the quantum confinement effect, which occurs when the physical dimensions of quantum dots reduce to a size smaller than the exciton Bohr radius of the material. 13 The common quantum dots that have attracted significant interest in the field of heavy metal sensing include CdSe, [14][15][16][17][18][19] CdTe, 20,21 ZnSe, [22][23][24] ZnS, 14 CdS, 16 ZnO, 25 carbon, 26,27 graphene, 28 and carbon nitride 29,30 QDs. Among them, the II-VI group quantum dots have larger Stokes shifts, high quantum yields, 31,32 narrow bandgaps, N-type nature, high absorption coefficient, high resistance to photobleaching, high charge mobility, and the capability to rapidly generate electron-hole pairs (charge carriers).…”

Advancements in semiconductor quantum dots: expanding frontiers in optoelectronics, analytical sensing, biomedicine, and catalysis

“…A significant obscuring of fluorescence was thought to be a sign of the selection of Hg 2+ ion. 221 Two structures of CdSe/ZnS CQDs, with varying solubility characteristics, were synthesized by Gilma Granados-Oliveros et al to detect Hg 2+ ions. In the first structure, CdSe/ZnS CQDs were capped with oleic acid (CdSe/ZnS/OA).…”