A research team at the Central University of Kerala has achieved a significant breakthrough in chemical sensing by developing a highly sensitive and selective cyanide sensor.
Led by Dr. Ravi Kumar Kanaparthi of the Department of Chemistry, the team has created a material capable of detecting toxic cyanide at low concentrations, promising to enhance the safety of drinking water and food products.
Cyanide, a potent toxin, is present in various plants, fruits, and microorganisms. The World Health Organisation (WHO) has set strict guidelines for its presence in potable water, limiting cyanide concentrations to below 0.19 mg/L due to its lethal effects on humans and aquatic life. Cyanide exposure can occur through consumption of certain foods like cassava (tapioca) and even common items like apple and apricot seeds, sprouting potatoes, and almonds. The risk is particularly severe in regions where cyanide-rich foods are staples.
Dr. Kanaparthi’s team addressed this critical need by designing a novel sensor that offers both high sensitivity and selectivity. The material they developed appears yellow to the naked eye when dissolved, but turns colourless upon detecting cyanide. This colour change provides a straightforward visual cue, making it easy to identify the presence of cyanide. Moreover, the material selectively detects cyanide without interference from other competing ions, ensuring accuracy in various testing environments.
The practical applications of the sensor are wide-ranging. The team demonstrated its effectiveness in detecting cyanide in tapioca extracts, where the sensor’s colour shifts from yellow to bluish-green, and developed a strip for qualitative detection. This strip changes colour upon cyanide exposure, providing a simple and efficient tool for field testing.
The innovation is especially relevant given recent incidents of cyanide poisoning. On January 2, 2024, the Animal Husbandry department reported the death of 13 cows in Idukki district due to cyanide toxicity after consuming tapioca hulls. This tragedy underscored the need for reliable cyanide detection methods, particularly in States like Kerala where tapioca is a dietary staple.
The research, which also involved contributions from Dr. Manjeev Singh and Sudeena Nadendla, has been published in the Journal of Photochemistry and Photobiology A: Chemistry. Their paper, titled “A Highly Sensitive Colorimetric and Fluorometric Sensor for the Detection of Cyanide,” details the sensor’s design and functionality. The team is also working on modifying the material for quantitative estimation of cyanide, which would allow for precise measurement of cyanide levels in various substances.
Dr. Kanaparthi emphasised the importance of the work, noting that cyanogenic glycosides in foods like tapioca, while not inherently toxic, could release hydrogen cyanide upon contact with enzymes in saliva, leading to fatal outcomes. This underscores the critical role that the sensor could play in preventing cyanide-related deaths and ensuring public safety.
The development of the sensor marks a significant advancement in chemical detection technology, with potential applications not only in Kerala but globally. It represents a promising tool for safeguarding human health against cyanide poisoning, whether in drinking water, food products, or industrial settings.