A New Fluorescence Sensor for Cerium (III) Ion Using Glycine Dithiocarbamate Capped Manganese Doped ZnS Quantum Dots.

A new fluorescence sensor for Ce(3+)ions is reported in this paper. This sensor is based on the fluorescence quenching of glycine dithiocarbamate (GDTC)-functionalized manganese doped ZnS quantum dots (QDs) in the presence of Ce(3+)ions. The synthesis of ultra-small GDTC-Mn:ZnS quantum dots (QDs) is based on the co-precipitation of nanoparticles in aqueous Solution. The nanoparticles are characterized with fluorescence spectroscopy, UV-vis absorption spectra, high-resolution transmission electron microscopy, X-ray power diffraction (XRD), and infrared spectroscopy. In the test carried out, it was found that the interaction between Ce(3+)ions and GDTC capped Mn:ZnS QDs quenches the original fluorescence of QDs according to the Stern-Volmer equation and the results show the existence of collisional quenching process. A linear relationship was observed between the extent of quenching and the concentration of Ce(3+)in the range of 2.0 × 10(-6) to 3.2 × 10(-5) mol.L(-1), with a detection limit of 2.29 × 10(-7) mol.L(-1). The relative standard deviation of 1.61% was obtained for five replicate measurements. The possible quenching mechanism was also examined by fluorescence and UV-vis absorption spectra. The interference of other cations was negligible on the quantitative determination of Ce(3+). This method proved to be simple, sensitive, low cost, and also reliable for practical applications.