Detection of Cd2+ in Aqueous Solution by the Fluorescent Probe of CdSe/CdS QDs Based on OFF-ON Mode

Dengpeng Wang; Feng Gao; Xianran Wang; Xiaomei Ning; Kaituo Wang; Xinpeng Wang; Yuezhou Wei; Toyohisa Fujita

doi:10.3390/toxics10070367

Detection of Cd²⁺ in Aqueous Solution by the Fluorescent Probe of CdSe/CdS QDs Based on OFF-ON Mode

Toxics. 2022 Jul 3;10(7):367. doi: 10.3390/toxics10070367.

Authors

Dengpeng Wang^{1

2}, Feng Gao^{1

2}, Xianran Wang^{1

2}, Xiaomei Ning^{1

2}, Kaituo Wang^{1

2}, Xinpeng Wang^{1

2}, Yuezhou Wei³, Toyohisa Fujita^{1

2}

Affiliations

¹ Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials, MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and Materials, Guangxi University, Nanning 530004, China.
² School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
³ School of Nuclear Science and Technology, University of South China, Hengyang 421001, China.

Abstract

The detection of heavy metals in aqueous solutions has always attracted much attention from all over the world. A fluorescent probe of CdSe/CdS core-shell quantum dots (QDs) was designed to detect trace Cd²⁺ in aqueous solutions using the OFF-ON mode rapidly and efficiently, likely based on adsorption and desorption reactions between ethylenediaminetetraacetic acid disodium salt (EDTA) and CdSe/CdS QDs. In the OFF mode, the optical shielding function of EDTA results in fluorescence quenching owing to the strong adsorption ability of EDTA with Cd²⁺ on the sites of CdSe/CdS QDs surface. In the ON mode, the introduction of Cd²⁺ promotes the desorption of EDTA from the EDTA-CdSe/CdS QDs and restores the fluorescence intensity. There were two linear response ranges which were 0.1-20 µmol/L and 20-90 µmol/L for the EDTA-CdSe/CdS system to detect Cd²⁺. The detection limit was 6 nmol/L, and the standard deviation was below 4% for the detection of Cd²⁺ concentration in tap water.

Keywords: Cd2+ detection; QDs; adsorption; desorption; fluorescence quenching; fluorescence restore.

Grants and funding

2019GXNSFAA185013/Programs for Natural Science Foundation of Guangxi