Zeitschrift für Umweltanalytische Chemie

Facile Sensor for Heavy Metals Based on Thiol-Capped CdTe Quantum Dot

Abstract

Souad A Elfeky

Background: Semiconductor Quantum Dots (QDs) have gained much attention in different fields of application due to exclusive photochemical reactions. They achieved a big triumph in supramolecular chemistry. A highly sensitive and specific nanosensor was reported in this study using QDs coated with acid for sensing Heavy Metal (HM) ions in water. Few relevant patents to the topic have been reviewed and cited in this article.
Methods: The Mercaptopropionic Acid (MPA)-capped CdTe QDs were prepared through a hydrothermal route and characterized by TEM, FTIR, UV/Vis, fluorescence and XRD techniques. Sensing of HM ions was performed in Deionized Water (DW) by titration of their respective salts with CdTe/MPA.
Results: TEM revealed that the QDs size diameter was in the range of 4 ± 0.2 nm. FTIR, UV/Vis, and fluorescence confirmed the structure and spectroscopic classification of QDs. XRD showed that CdTe/MPA crystals were cubic. Based on the fact that the QDs fluorescence possibly quench by HM ions, an easy process for HM detection was anticipated. The QDs response showed a direct correlation to the concentration of HM. The synthesized QDs had potential for detecting the HM ions with higher selectivity to Mercury ions (Hg2+) in water compared with Lead (Pb2+) and Barium (Ba2+). The optimum sensor sensitivity was achieved at pH 8.
Conclusion: HM ions quenching CdTe/MPA fluorescence in a concentration-dependent manner. The method presented in this manuscript is novel, economical and convenient for realistic applications.