Selective and sensitive fluorescent nanoprobe based on AgInS2-ZnS quantum dots for the rapid detection of Cr (III) ions in the midst of interfering ions

Sundararajan Parani; Oluwatobi Samuel Oluwafemi

doi:10.1088/1361-6528/ab9c58

Selective and sensitive fluorescent nanoprobe based on AgInS₂-ZnS quantum dots for the rapid detection of Cr (III) ions in the midst of interfering ions

Nanotechnology. 2020 Sep 25;31(39):395501. doi: 10.1088/1361-6528/ab9c58. Epub 2020 Jun 12.

Authors

Sundararajan Parani¹, Oluwatobi Samuel Oluwafemi

Affiliation

¹ Department of Chemical Sciences (formerly Applied Chemistry), University of Johannesburg, P.O. Box 17011, Doornfontein, 2028, Johannesburg, South Africa. Centre for Nanomaterials Science Research, University of Johannesburg, P.O. Box 17011, Doornfontein, 2028, Johannesburg, South Africa.

PMID: 32531766
DOI: 10.1088/1361-6528/ab9c58

Abstract

We herein report a novel eco-friendly method for the fluorescent sensing of Cr (III) ions using green synthesized glutathione (GSH) capped water soluble AgInS₂-ZnS (AIS-ZnS) quantum dots (QDs). The as-synthesized AIS-ZnS QDs were speherical in shape with average diameter of ∼2.9 nm and exhibited bright yellow emission. The fluorimetric analyses showed that, compared to Cr (VI) ions and other 20 metal ions across the periodic table, AIS-ZnS QDs selectively detected Cr (III) ions via fluorescent quenching. In addition, AIS-ZnS QDs fluorescent nanoprobes exhibited selective detection of Cr (III) ions in the mixture of interfering divalent metal ions such as Cu (II), Pb (II), Hg (II), Ni (II). The mechanism of Cr (III) sensing investigated using HRTEM and FTIR revealed that the binding of Cr (III) ions with the GSH capping group resulted in the aggregation of QDs followed by fluorescence quenching. The limit of detection of Cr (III) ions was calculated to be 0.51 nM. The present method uses cadmium free QDs and paves a greener way for selective determination of Cr (III) ions in the midst of other ions in aqueous solutions.