This sugarcane skin can sense arsenic

Sugarcanes don't just yield sugar: they may be used as sensors, too. Researchers from the Indian Institute of Technology (IIT) Kanpur have developed a sustainable sensing platform made of sugarcane fibres for arsenic detection. These fibres are extracted from sugarcane skin, a biodegradable and non-toxic agricultural waste.

High arsenic levels in food items such as rice, potato, and wheat caused by contaminated groundwater and soil are a growing health concern and require frequent checks of arsenic levels in food samples. However, such checks lead to waste generation as the commonly used heavy metal detection kits include plastic, ceramic, and glass substrates as sensing platforms. Researchers have been working on biodegradable paper detection strips, but making paper is water-intensive.

IIT Kanpur Professor Siddhartha Panda and his PhD student Nachiket Aashish Gokhale have a solution. They have found that sugarcane peels have a natural nanostructure that increases the surface area required for better detection of analytes. Sugarcane mills also descale the sugarcane skin before processing it, so the peel is a natural waste that can be a cheap substitute for ceramic and plastic. "It is slightly hydrophobic, so the fluid doesn't seep into the substrate while measurements are done," Gokhale says, explaining why it makes for an appropriate sensing platform.

The researchers manually descaled sugarcane skin and rolled it to turn it into flat substrates. After some initial hiccups, the team used these fibres to develop a sensing platform in 2024. The platform, called SugarcaneSens, was compared with other systems. Panda says that pollution levels on the sugarcane platform are one-hundredth of those on a plastic or a ceramic platform.

To make the platform sense arsenic, the team electro-deposited gold nanorods over it. In its research published in Microchemical Journal (bit.ly/arsenic-sensor), the team shows that the sensor can accurately detect arsenic concentrations between 2 parts per billion and 1,000 parts per billion. Arsenic detection is not affected by the presence of other ions such as cadmium, cobalt, copper, iron, nickel, lead and zinc. The sensor was stable and reproducible as well.

Musthafa Ottakam Thotiyl, Professor at the Indian Institute of Science Education and Research Pune, says the team's approach is aligned with India's national mission to address arsenic contamination in water.