Cyano-determined mercury (II) ion selective fluorescence assay over polymeric carbon nitride

Jing Zhang; Tao Sun; Jiang Wang; Ai-Ju Xu; Bin Xue

doi:10.1016/j.saa.2024.125129

Cyano-determined mercury (II) ion selective fluorescence assay over polymeric carbon nitride

Spectrochim Acta A Mol Biomol Spectrosc. 2025 Jan 15:325:125129. doi: 10.1016/j.saa.2024.125129. Epub 2024 Sep 12.

Authors

Jing Zhang¹, Tao Sun², Jiang Wang³, Ai-Ju Xu³, Bin Xue⁴

Affiliations

¹ Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
² Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Laboratory of Quality and Safety Risk Assessment for Aquatic Product on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai 201306, China; National Experimental Teaching Demonstration Center for Food Science and Engineering (Shanghai Ocean University), Shanghai 201306, China.
³ College of Chemistry and Environmental Science, Inner Mongolia Key Laboratory of Green Catalysis, Inner Mongolia Normal University, Hohhot 010022, China.
⁴ Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Laboratory of Quality and Safety Risk Assessment for Aquatic Product on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai 201306, China; National Experimental Teaching Demonstration Center for Food Science and Engineering (Shanghai Ocean University), Shanghai 201306, China; Marine Biomedical Science and Technology Innovation Platform of Lingang Special Area, Shanghai 201306, China. Electronic address: bxue@shou.edu.cn.

PMID: 39288603
DOI: 10.1016/j.saa.2024.125129

Abstract

Selective response is the key index to evaluate the performance of polymeric carbon nitride (PCN)-based heavy metal ion fluorescence sensors. Herein, to explore the role of cyano groups on selectivity, four kinds of PCN, including PCN-Cl, PCN-Ac, PCN-B and PCN-K were prepared by the molten salt method of sodium chloride and sodium acetate, the reduction method of sodium borohydride and the etching method of potassium hydroxide, respectively. These PCNs exhibited different surface cyano characteristics, but all of them had significant blue emission under ultraviolet excitation. It is proved that the assistant of sodium chloride or potassium hydroxide is an effective method to prepare PCNs with abundant surface cyano group. A series of fluorescence quenching experiments of metal ions showed that the cyano-rich degree of PCN is closely related to its selective response to mercury (II) ions. PCN-Cl and PCN-K emerged good selective quenching of mercury (II) ions, which may be related to the soft acid-soft base strong interaction between mercury (II) ions and cyano groups. Both PCN-Cl and PCN-K fluorescent probes for mercury (II) ions had a linear range of 5 ∼ 50 μmol L^-1, and PCN-Cl exhibited a lower detection limit of 0.38 μmol L^-1. This work confirmed the selective fluorescence response of cyano-rich PCN to mercury (II) ions, proposed the mechanism of selective fluorescence quenching response of mercury (II) ions, and provided a new idea for the design of efficient and accurate PCN-based fluorescence probes.

Keywords: Cyano groups; Fluorescence quenching; Mercury (II) ions; Polymeric carbon nitride; Selectivity.