Interdisciplinary research is now essential to address the challenges of the society especially environmental related issues. Lethal anions are the major pollutants in various industrial and municipal effluents, which create a serious threat to living-organisms. Cyanide (CN^-) is one of the most perilous anions and causes deadly impacts on animals, specifically on mammals. It results in numerous fatal effects, like queasiness, paroxysm, unconsciousness and eventually death, which are propelling the urge of its instantaneous detection even at a very low level. Various sophisticated instruments (like atomic absorption spectroscopy, mass spectrometry, chromatography, Raman spectroscopy etc.) are available which are highly expensive and mostly not handy for field studies. Therefore, exploration of neoteric chemosensors, explicitly colourimetric sensory probes, can be a leading-edge, cheap, lightweight and handy solution to the society for easy, instant and on-site recognition of ionic contaminants by producing a visible colourimetric alteration. Moreover, conducive, low-cost, accessible point-of-care-testing (POCT) devices are anticipated to take a pivotal role in the determination of perilous elements. In this context, the effectual synchronization of the chemosensors within the Point of care testing (POCT) device is of extensive usage to the common people for easily recognizing CN^- like hazardous elements.

In our attempt to address these environmental issues, a distinctive urea-based chemosensor, DTPH [1,5-bis(2,6-dichloro-4-(trifluoromethyl)-phenyl)carbonohydrazide) has been synthesized, which can selectively recognize CN^-. The colourimetric, fluorimetric and electrochemical responses of this newly developed chemosensor with CN^- are well supported by numerous wet-chemical and theoretical studies. Additionally, DTPH can recognize CN^- in the almond seed, fetal bovine serum as well as in the human lungs carcinoma and HeLa cells. Furthermore, DTPH...CN^– adduct shows intense sensitivity towards Hg²⁺ which can be synchronized as a futuristic tool in the fabrication of chemical-response-based electronic circuitry. Most interestingly, the concentration-dependent colourimetric variation, instigated in developing an easy, portable, rapid, RGB-based sensory device to articulately differentiate the nontoxic and toxic concentrations of CN⁻ within a solution, which will definitely be a substantial imprint towards recent progression on Point-of-care testing (POCT) devices.

Priyabrata Banerjee

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