Carbon dots electrochemically prepared from dopamine and epigallocatechin gallate for hypochlorite detection with high selectivity via a dynamic quenching mechanism

Tiantian Long; Zhongyang Hu; Ziyun Gao; Hongmei Luo; Hongchen Li; Yi Chen; Lei Liu; Dong Xu

doi:10.1016/j.saa.2023.122947

Carbon dots electrochemically prepared from dopamine and epigallocatechin gallate for hypochlorite detection with high selectivity via a dynamic quenching mechanism

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Nov 15:301:122947. doi: 10.1016/j.saa.2023.122947. Epub 2023 Jun 1.

Authors

Tiantian Long¹, Zhongyang Hu², Ziyun Gao³, Hongmei Luo⁴, Hongchen Li⁴, Yi Chen⁵, Lei Liu⁶, Dong Xu⁷

Affiliations

¹ The Health Management Department of the Third Xiangya Hospital, Central South University, Changsha 410013, China; National Engineering Laboratory for Rice and By-products Further Processing, College of Food Science and Engineering, Central South University of Forestry & Technology, Changsha 410004, China; College of Food Science and Engineering, Xinjiang Institute of Technology, Aksu 843100, China.
² The Neurology Department of the Third Xiangya Hospital, Central South University, Changsha 410013, China.
³ Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China.
⁴ The Health Management Department of the Third Xiangya Hospital, Central South University, Changsha 410013, China.
⁵ Hunan Intellijoy Biotechnology Co., Ltd., Changsha, Hunan 410125, China.
⁶ The Health Management Department of the Third Xiangya Hospital, Central South University, Changsha 410013, China. Electronic address: Liulei19890403@163.com.
⁷ National Engineering Laboratory for Rice and By-products Further Processing, College of Food Science and Engineering, Central South University of Forestry & Technology, Changsha 410004, China. Electronic address: philip198349@gmail.com.

PMID: 37295382
DOI: 10.1016/j.saa.2023.122947

Abstract

Monitoring hypochlorite levels in water is of great importance because of its high toxicity and wide applications as water disinfectants. In this manuscript, carbon dot (CD) was electrochemically prepared by using dopamine and epigallocatechin gallate (molar ratio 1:1) as the carbon source for efficient hypochlorite determination. By electrolyzing the solution at 10 V for 12 min with PBS as an electrolyte, dopamine would react with epigallocatechin at the anode, and through polymerization, dehydration, and carbonization, strong blue-fluorescent CDs were obtained. CDs were characterized by UV-Vis spectroscopy, fluorescence spectroscopy, high-resolution transmission electron microscopy, FT-IR, etc. These CDs have an excitation wavelength at 372 nm and an emission wavelength at 462 nm, owing an average particle size of 5.5 nm. The presence of hypochlorites can quench the fluorescence of CDs, and its reduction in intensity is linear with hypochlorite concentration over the range of 0.5-50 μM, ΔF/F₀ = 0.0056 + 0.0194C_ClO^-, R²=0.997. The detection limit achieved 0.23 μM (S/N = 3). The mechanism for fluorescence quenching is via a dynamic process. Different from many other fluorescence methods based on the strong oxidizing ability of hypochlorites, our method shows strong selectivity toward hypochlorites over other oxidizing agents such as H₂O₂. The assay was validated by the detection of hypochlorites in water samples, with recoveries between 98.2% and 104.3%.

Keywords: Carbon dots; Dynamic quenching; Electrochemical method; Fluorescence; Hypochlorite.

MeSH terms

Carbon / chemistry
Dopamine
Fluorescent Dyes / chemistry
Hydrogen Peroxide
Hypochlorous Acid
Quantum Dots* / chemistry
Spectroscopy, Fourier Transform Infrared
Water

Substances

Hypochlorous Acid
Dopamine
Carbon
Hydrogen Peroxide
epigallocatechin gallate
Water
Fluorescent Dyes