Guwahati: Researchers at the Indian Institute of Technology Guwahati (IIT-G) have developed an advanced fluorescent sensor capable of detecting cyanide in both water and human cells using only UV light, according to an official release on Monday.
The newly developed sensor exhibits a colour change and emits bright fluorescence when exposed to cyanide, making it a valuable tool for environmental safety and forensic investigations, the IIT Guwahati statement revealed.
Cyanide, a highly toxic substance, is commonly used in industrial processes like synthetic fibre manufacturing, metal cleaning, plastics production, electroplating, and gold mining.
Improper disposal of cyanide can lead to contamination of soil and water, and its consumption disrupts the oxygen supply in the human body.
Even small amounts of cyanide can have severe health consequences or result in death, highlighting the need for accurate detection methods.
Fluorescent chemosensors, which light up when interacting with specific chemicals, are favoured due to their simplicity, affordability, and high sensitivity.
While many existing sensors rely on a “turn-off” response (dimming their light when detecting a substance), the IIT Guwahati team developed a “turn-on” response sensor, where the signal brightens, offering better detection clarity and avoiding false negatives.
Led by Professor G. Krishnamoorthy of the Department of Chemistry, the IIT-G team created a “turn-on” chemosensor using a compound called 2-(4′-diethylamino-2′-hydroxyphenyl)-1H-imidazo-[4,5-b]pyridine.
Under UV light, this compound initially emits weak blue fluorescence, which intensifies and shifts to a cyan colour in the presence of cyanide, due to a chemical change in the molecule.
This response is highly specific to cyanide, especially in a carefully chosen solvent system that includes water.
The team validated the sensor’s effectiveness through laboratory experiments and advanced computational calculations, specifically DFT (Density Functional Theory) calculations, which confirmed the sensing mechanism.
“What makes this sensor unique is its versatility,” stated Prof. Krishnamoorthy.
“It works effectively not only in laboratory solutions but also in river and tap water samples, achieving an accuracy range of 75–93 percent. Additionally, it can be integrated into paper strips for portable, on-site testing and has proven effective in live cell imaging. We’ve even used it to detect cyanide within biological cells, demonstrating its potential for both environmental and forensic applications.”
The research team also discovered that this sensor can function like a basic logic gate, a key component in digital electronics.
This capability suggests that the sensor could have future applications in the development of smart, sensor-based electronic devices capable of detecting harmful chemicals like cyanide in real-time.
Published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, the study was a collaborative effort between Prof. Krishnamoorthy and Prof. Bithiah Grace Jaganathan of the Department of Bioscience and Bioengineering at IIT Guwahati.
Research scholars Mongoli Brahma, Arup Das Kanungo, Minati Das, and Sam P. Mathew were also involved in the development of the sensor.
Looking ahead, the research team is focused on creating a simplified testing kit for analysing a variety of harmful substances, further expanding the potential applications of this innovative technology.
