One-Step Assembly of Fluorescence-Based Cyanide Sensors from Inexpensive, Off-The-Shelf Materials

• Published in: Sensors (Basel, Switzerland) Vol. 20; no. 16; p. 4488
• Main Authors: Fernandes, Gregory E., Chang, Ya-Wen, Sharma, Akash, Tutt, Sarah
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 11.08.2020; MDPI
• Subjects: Antifungal agents; Chromatography; complex; fluorescence; Fourier transforms; non-covalent; off-on; Polymers; sensor; Sensors; turn-on
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s20164488

We report a simple and versatile approach to assemble sensitive and selective fluorescence “turn-on” sensors for cyanide by combining three off-the-shelf materials; namely fluorescent dye, 1-vinyl imidazole polymer, and cupric chloride. The cyanide-sensing species is a non-fluorescent fluorophore-polymer-Cu2+ complex; which forms as a result of the imidazole polymer’s ability to bind both fluorophore and fluorescence quencher (Cu2+). Cyanide removes Cu2+ from these complexes; thereby “turning-on” sensor fluorescence. These sensors are water-soluble and have a detection limit of ~2.5 μM (CN−) in water. Our ternary complex-based sensing approach also enables facile emission tuning; we demonstrate the convenient, synthesis-free preparation of blue and green-emitting sensors using distyrylbiphenyl and fluorescein fluorophores, respectively. Furthermore; these ternary complexes are easily immobilized using agarose to create cyanide-sensing hydrogels; which are then used in a simple; novel microdiffusion apparatus to achieve interference-free cyanide analysis of aqueous media. The present study provides an inexpensive approach for portable; interference-free cyanide detection.