Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution

Wang, Zhezhe; Xiao, Xuechun; Zou, Tong; Yang, Yue; Xing, Xinxin; Zhao, Rongjun; Wang, Zidong; Wang, Yude

doi:10.3390/nano9010032

Open AccessArticle

Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution

by

Zhezhe Wang

^1,2,

Xuechun Xiao

^2,*,

Tong Zou

¹,

Yue Yang

²,

Xinxin Xing

²,

Rongjun Zhao

^1,2,

Zidong Wang

¹ and

Yude Wang

^1,3,*

¹

School of Materials Science and Engineering, Yunnan University, Kunming 650091, China

²

Department of Physics, Yunnan University, Kunming 650091, China

³

Key Lab of Quantum Information of Yunnan Province, Yunnan University, Kunming 650091, China

^*

Authors to whom correspondence should be addressed.

Nanomaterials 2019, 9(1), 32; https://doi.org/10.3390/nano9010032

Submission received: 5 November 2018 / Revised: 20 December 2018 / Accepted: 20 December 2018 / Published: 27 December 2018

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Abstract

Citric acid capped CdS quantum dots (CA-CdS QDs), a new assembled fluorescent probe for copper ions (Cu²⁺), was synthesized successfully by a simple hydrothermal method. In this work, the fluorescence sensor for the detection of heavy and transition metal (HTM) ions has been extensively studied in aqueous solution. The results of the present study indicate that the obtained CA-CdS QDs could detect Cu²⁺ with high sensitivity and selectivity. It found that the existence of Cu²⁺ has a significant fluorescence quenching with a large red shifted (from greenish-yellow to yellowish-orange), but not in the presence of 17 other HTM ions. As a result, Cu₂S, the energy level below the CdS conduction band, could be formed at the surface of the CA-CdS QDs and leads to the quenching of fluorescence of CA-CdS QDs. Under optimal conditions, the copper ions detection range using the synthesized fluorescence sensor was 1.0 × 10^‒8 M to 5.0 × 10^‒5 M and the limit of detection (LOD) is 9.2 × 10^‒9 M. Besides, the as-synthesized CA-CdS QDs sensor exhibited good selectivity toward Cu²⁺ relative to other common metal ions. Thus, the CA-CdS QDs has potential applications for detecting Cu²⁺ in real water samples.

Keywords: fluorescence sensor; citric acid; CdS quantum dots; copper ions; high selectivity

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MDPI and ACS Style

Wang, Z.; Xiao, X.; Zou, T.; Yang, Y.; Xing, X.; Zhao, R.; Wang, Z.; Wang, Y. Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution. Nanomaterials 2019, 9, 32. https://doi.org/10.3390/nano9010032

AMA Style

Wang Z, Xiao X, Zou T, Yang Y, Xing X, Zhao R, Wang Z, Wang Y. Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution. Nanomaterials. 2019; 9(1):32. https://doi.org/10.3390/nano9010032

Chicago/Turabian Style

Wang, Zhezhe, Xuechun Xiao, Tong Zou, Yue Yang, Xinxin Xing, Rongjun Zhao, Zidong Wang, and Yude Wang. 2019. "Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution" Nanomaterials 9, no. 1: 32. https://doi.org/10.3390/nano9010032

APA Style

Wang, Z., Xiao, X., Zou, T., Yang, Y., Xing, X., Zhao, R., Wang, Z., & Wang, Y. (2019). Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution. Nanomaterials, 9(1), 32. https://doi.org/10.3390/nano9010032

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Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution

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