Nitrogen and sulfur co-doped carbon quantum dots fluorescence quenching assay for detection of mercury (II)

Mosayeb Chaghaghazardi; Soheila Kashanian; Maryam Nazari; Kobra Omidfar; Yvonne Joseph; Parvaneh Rahimi

doi:10.1016/j.saa.2023.122448

Nitrogen and sulfur co-doped carbon quantum dots fluorescence quenching assay for detection of mercury (II)

Spectrochim Acta A Mol Biomol Spectrosc. 2023 May 15:293:122448. doi: 10.1016/j.saa.2023.122448. Epub 2023 Feb 4.

Authors

Mosayeb Chaghaghazardi¹, Soheila Kashanian², Maryam Nazari³, Kobra Omidfar⁴, Yvonne Joseph⁵, Parvaneh Rahimi⁵

Affiliations

¹ Faculty of Chemistry, Razi University, Kermanshah, Iran; Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
² Faculty of Chemistry, Razi University, Kermanshah, Iran; Nanobiotechnology Department, Faculty of Innovative Science and Technology, Razi University, Kermanshah, Iran. Electronic address: kashanian_s@yahoo.com.
³ Faculty of Chemistry, Razi University, Kermanshah, Iran.
⁴ Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran; Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
⁵ Institute of Electronic and Sensor Materials, Faculty of Materials Science and Materials Technology, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany; Freiberg Center for Water Research, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany.

PMID: 36773423
DOI: 10.1016/j.saa.2023.122448

Abstract

Mercury is a highly toxic and potentially bioaccumulative heavy metal ion that can cause severe health problems in humans even at very low concentrations. Thus, the development of a simple, rapid, and sensitive assay for the effective detection of mercury ions at trace levels is of great importance. Here, nitrogen and sulfur co-doped carbon quantum dots (N,S-CQD) were synthesized by a simple hydrothermal treatment of chitosan in the presence of thiourea and citric acid with a quantum yield (QY) up to 33.0 % and used as a selective fluorescent probe to detect mercury ions (Hg²⁺). The effect of pH, ionic strength, and time on the fluorescence intensity of N,S-CQD were investigated and optimized. The synthesized N,S-CQD showed ultrasensitive ability to detect Hg²⁺ ions in the water samples, also in the presence of 11 interfering metal ions, with a low detection limit (∼4 nM) over a wide linear range from ∼5-160 nM. The sensing performance of N,S-CQD probe in real sample applications was evaluated by the detection of Hg²⁺ in lake water samples, which confirmed its potential application in environmental analysis.

Keywords: Carbon quantum dots; Chitosan; Fluorescence quenching; Mercury sensor; Nitrogen and sulphur doping.