A circular dichroism sensor for selective detection of Cd2+ and S2- based on the in-situ generation of chiral CdS quantum dots

Pradthana Sianglam; Sirinan Kulchat; Thawatchai Tuntulani; Wittaya Ngeontae

doi:10.1016/j.saa.2017.04.071

A circular dichroism sensor for selective detection of Cd²⁺ and S^2- based on the in-situ generation of chiral CdS quantum dots

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Aug 5:183:408-416. doi: 10.1016/j.saa.2017.04.071. Epub 2017 Apr 26.

Authors

Pradthana Sianglam¹, Sirinan Kulchat¹, Thawatchai Tuntulani², Wittaya Ngeontae³

Affiliations

¹ Materials Chemistry Research Center, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
² Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
³ Materials Chemistry Research Center, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: wittayange@kku.ac.th.

PMID: 28475982
DOI: 10.1016/j.saa.2017.04.071

Abstract

We demonstrate an advance in the fabrication of circular dichroism (CD) sensors for detection of Cd²⁺ and S^2- based on chiral CdS quantum dots (QDs) generated by a facile in-situ reaction. The chiral quantum dots are generated in solutions composed of Cd²⁺, S^2-, cysteamine (CA) and L-penicillamine (L-PA), with the number of the generated particles limited by either the Cd²⁺ or S^2- concentration. We show that the magnitude of the CD signal produced by the QDs is linearly related to the initial concentration of Cd²⁺ and S^2-, with excellent selectivity over other ions. Our sensor functions over concentration ranges of 65-200μM and 7-125μM with detection limits of 59.7 and 1.6μM for Cd²⁺ and S^2-, respectively. The sensor is applied in real water samples with results comparing favorably with those obtained from ICP-OES (for Cd²⁺) and HPLC (for S^2-).

Keywords: Chemical sensor; Chiral nanoparticle; Circular dichroism sensor; Heavy metal ions; Quantum dots; Sulfide ion.