چكيده به لاتين
In the present study, water-soluble lead sulfide nanocrystals have been successfully synthesized to detect arsenic in water. because of the certain benefits of nanomaterials-based sensors, for example, large surface area and strong adsorption capacity have indicated excellent performance for the detection of heavy metals. PbS quantum dots were selected because of their excellent optical features such as the large exciton Bohr radius that occurs in strong quantum confinement and their size-dependent optical properties. The surface functionalization with amino acids as a biofunctionalized agent causes at the same time to passivate the surface, increase the solubility of the QDs and make suitable their surface for selective interactions with metal ions. The obtained sensor was characterized by XRD, FT-IR, UV-VIS, TEM and fluorescence. The method is based on the fluorescence quenching of PbS QDs by the addition of the arsenic solution. Under optimum conditions, the fluorescence quenching effect of Methionine capped PbS QDs was linear at As3+ concentrations in the range of 5-150 ppb and the detection limit was calculated to be 3.7 ppb. Then the effect of the desired sensor on the other metal ions in the water was studied separately. Comparison and analysis of the obtained spectra showed that the synthesized sensor had good selectivity over other metal ions in water. Proper emission spectrum, high optical stability, low cost, water solubility and biocompatibility are the advantages of the designed sensor.
