Synthesis and characterization of novel bithiazolidine derivatives-capped CdTe/CdS quantum dots used as a novel Hg2+ fluorescence sensor

Abstract

In the present study, (E)-2,2'-(4,4'-dioxo-2,2'-dithioxo-2H,2'H-[5,5'-bithiazolylidene]-3,3'(4H,4'H)-diyl) bis(3-mercaptopropanoic acid) (DTM) as a new derivative of thiazolidine was synthesis and characterized for the detrtmination of Hg²⁺ ions. Then, the CdTe@CdS QDs and DTM capped CdTe@CdS QDs were produced. The DTM-CdTe@CdS/QDs used as an effective fluorescence sensing material due to the selective interaction of DTM with Hg (II). The results indicated that the DTM-CdTe@CdS/QDs shows strong fluorescence emissions in the absence of mercury ions and efficiently quenched in presence of Hg², with the formation of a strong and stable complex between Hg²⁺ and DTM. Experimental results showed that under optimal conditions, Hg²⁺ could be detected with a detection limit of 0.08 nM in a linear range from 0.3 nM to 21 nM. The constructed aptasensor illustrated the high selectivity for mercury ions even in the presence of the other interfering metal ions when their concentration ratio was more than 300 times. The satisfactory results illustrated that the designed fluorescence sensor as a sensitive, reliable and easy to use approach could be applied for the facile and rapid determination of Hg²⁺ in tap water.

Keywords: CdTe@CdS quantum dots; Fluorescence; Mercury; Thiazolidine.