Study of fluorescence quenching of mercaptosuccinic acid‐capped CdS quantum dots in the presence of some heavy metal ions and its application to Hg(II) ion determination

In this study, CdS quantum dots (QDs) capped with mercaptosuccinic acid (MSA) were prepared in one step. The size, shape, component and spectral properties of MSA‐capped CdS QDs were characterized by transmission electron microscopy (TEM), photoluminescence (PL) and infrared (IR) spectrometry. The results showed that the prepared QDs with an average diameter of 6 nm have favorable fluorescence, which is greatly influenced by the pH of the environment. The interaction of some heavy metal ions including Ag⁺, Hg²⁺, Cu²⁺, Ni²⁺ and Co²⁺ with MSA‐capped CdS QDs was investigated in different buffering pH media. Based on the fluorescence quenching of the QDs in the presence of each of the metal ions, the feasibility of their determinations was examined according to the Stern–Volmer equation. The investigations showed that Hg(II) ions can be determined in the presence of many co‐existing metal ions at a buffering pH of 5. This method was satisfactorily applied to the measurement of Hg(II) ions in some environmental samples. Copyright © 2014 John Wiley & Sons, Ltd.