A Highly Selective Colorimetric Naked-Eye Probe for Hypochlorite Detection in Water

Yu, Qing; Chen, Xiao Li; Zhang, Qi Long; Liu, Hua; Yang, Xian Jiong; Xu, Hong; Huang, Ya Li; Feng, Xing; Redshaw, Carl

Abstract

The real-time detection and monitoring of hypochlorites (ClO-) in water is highly challenging. An excellent colorimetric "naked-eye" probe photoacid (PAH) was synthesized. PAH was comfirmed using High-Resolution Mass Spectrometry (HRMS), 1H NMR and 13C NMR. The interaction between PAH and ClO- was investigated via UV-Vis absorption spectrophotometry under different pH conditions. The results indicated that PAH was completely soluble in water, PAH displayed a yellow solution in a phosphate buffer with a pH of 2.0 to 5.0, and the maximum absorption peak was at 424 nm. PAH displayed a purple solution in a phosphate buffer with a pH of 6.0~12.0, and the maximum absorption peak was at 532 nm. After adding ClO- to different pH systems, PAH discoloration and the UV-Vis absorption peak disappeared. The probe PAH exhibited specific selectivity and sensitivity for ClO- detection with a low detection limit in the pH 5.0 phosphate buffer. After PAH reacted with ClO-, the absorption peak of the probe at 424 nm gradually decreased, and a new absorption peak appeared at 532 nm. The probe displayed a vivid color-tunable process from yellow to purple then to colorless with a fast response time for ClO- detection. However, other common 33 substances such as metal ions(Li+, Co2+, Cr3+, K+, Cd2+, Pb2+, Ca2+, Hg2+, Ba2+, Cu2+, Mg2+, Ni2+, Zn2+, Al3+ and Fe3+), anions (NO2-, I-, AcO-, ClO4-, SO42-, CN-, Br-, CO32- and F-), reactive oxygen species (ROO•, •OH, H2O2, •O2-, tBuOOH, tBuO• and 1O2) and reactive nitrogen species (ONOO- and NO•), did not cause changes in the color of the probe solution and the UV-Vis absorption spectrum. The above species had only a limited effect on detecting the ClO- anion. When they coexisted with ClO-, the probe also showed a similar solution color change, and the absorption peak at 424 nm disappeared. Meanwhile, the probe PAH could quantitatively detect the content of ClO- with a detection limit of 5.39 μmol•L-1 (y=1.586 78-0.524 51x, R2=0.998 52). Furthermore, ClO- concentration in the water system (84 disinfectant and tap water) was analyzed. The average concentration of ClO- ion in the tap water measured by three parallel tests was 7.96 μmol•L-1 with high recoveries rate. It showed that PAH could also be utilized to detect ClO- quantitatively in real water systems.

Citation

Yu, Q., Chen, X. L., Zhang, Q. L., Liu, H., Yang, X. J., Xu, H., …Redshaw, C. (2022). A Highly Selective Colorimetric Naked-Eye Probe for Hypochlorite Detection in Water. Spectroscopy and Spectral Analysis, 42(1), 322-332. https://doi.org/10.3964/j.issn.1000-0593%282022%2901-0322-11

• Journal Article Type: Article
• Acceptance Date: Nov 9, 2020
• Online Publication Date: Jan 20, 2022
• Publication Date: 2022
• Deposit Date: Mar 9, 2022
• Publicly Available Date: Jun 8, 2022
• Journal: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis
• Print ISSN: 1000-0593
• Publisher: Peking University Press
• Peer Reviewed: Peer Reviewed
• Volume: 42
• Issue: 1
• Pages: 322-332
• DOI: https://doi.org/10.3964/j.issn.1000-0593%282022%2901-0322-11
• Keywords: Colorimetric probe; Hypochlorite anion; Rapid response; High selectivity
• Public URL: https://hull-repository.worktribe.com/output/3911342
• Publisher URL: http://www.gpxygpfx.com/article/2022/1000-0593-42-1-322.html