Emergence of the selective ultra-sensing of Ag(I): Thiolactic acid as efficient capping agent for cadmium chalcogenide quantum dots in modulating photoluminescence and metal reception

Niharendu Mahapatra, Abhijit Mandal, Sudipta Panja, Mintu Halder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Stable and water-soluble cadmium telluride quantum dots (CdTe QDs) have been employed for ultra-sensing exclusive to water soluble Ag(I). For this purpose we have designed and synthesized thiolactic acid (TLA) capped exquisite CdTe QDs having exclusive selectivity for silver. The limit of detection (LOD) of Ag(I) is 50 nM . The pendant methyl group of TLA effectively impedes the precursor aggregation by inhibiting the secondary coordination of carboxyl oxygen of mercapto acid with the surrounding Cd(II), and this results in highly luminescent TLA-CdTe QDs. This pendant methyl group of TLA also facilitates exclusive surface adsorption of QDs by incoming metal and renders sensing selectivity. Selective adsorption of silver on TLA-CdTe QD surface provides a turn-off photoluminescence-based assay for sensitive detection of Ag(I) without any interference of other commonly coexisting metal ions. Furthermore, analyses of environmental water samples spiked with Ag(I), demonstrate immense practical potential of our TLA-CdTe QD sensor for the detection of silver in real samples. The results also unveiled the possible origin of the sensing selectivity for metal ion by TLA-capped QDs which can serve in the design and selection of appropriate capping in achieving the desired sensing selectivity.

Original languageEnglish
Pages (from-to)543-552
Number of pages10
JournalSensors and Actuators, B: Chemical
Volume240
DOIs
StatePublished - 1 Mar 2017
Externally publishedYes

Keywords

  • Ag(I) sensing
  • Capping ligand
  • Selective-ultrasensitive detection
  • TLA-CdTe quantum dots
  • Turn-off-photoluminescence

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