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Updated: Feb 4, 2026

An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
Fluorescent imidazole-based chemosensors for the reversible detection of cyanide and mercury ions
Ganapathi Emandi1, Keith J Flanagan, Mathias O Senge
1SFI Tetrapyrrole Laboratory, School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland.
Abstract:
We report 4-(2-(5-(tert-butyl)-3-formyl-2-hydroxyphenyl)-1H-phenanthro[9,10-d]imidazol-1-yl)benzoic acid 1 and 4-(2-(5-(tert-butyl)-3-formyl-2-hydroxyphenyl)-4,5-diphenyl-1H-imidazol-1-yl)benzoic acid 2 as reversible luminescent sensors for the detection of cyanide and mercury ions. These imidazole derivatives were characterized using spectroscopic techniques and single crystal X-ray crystallography. The compounds showed sensing exclusively towards CN- ions, which resulted in the quenching of fluorescence and a decreased singlet state life time. The detection limit of imidazole derivatives 1 and 2 were found to be 0.8 μM and 1.2 μM respectively, in a CH3CN/H2O system. Job's plot analysis, 1H NMR spectra and LC-MS studies supported the formation of the respective cyanohydrin. This cyanohydrin was further used as a reversible sensor for the detection of Hg2+ ions through metal-assisted elimination. The reversibility and reusability of sensors for the detection of CN- and Hg2+ ions were tested for four consecutive cycles.
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