Scientists from Department of Physics, Guwahati University, Assam have developed a cost-effective formalin sensor using tin oxide-reduced graphene oxide composite that can effectively detect the presence of formalin in adulterated fishes at room temperature in a non-invasive way. The sensor shows long-term stability with a low detection limit.
Food adulteration is the practice of adding illegal or harmful substances to food to make it appear more appealing or to increase its shelf life. Formaldehyde is a colourless, pungent gas that is used in a variety of industrial processes, including as a preservative in some foods, commonly in fish in developing countries. However, the use of formaldehyde in food is illegal in many countries, as it is a known carcinogen.
Commercial formalin sensors for fish are primarily electrochemical-based or colorimetric-based. Electrochemical sensors are extensively used but are expensive. On the other hand, calorimetric sensors are less expensive. But both methods are invasive in nature, according to a statement here from the Department of Science and Technology.
Moreover, low-level detection and selective detection are two major issues with these sensors. The development of 2D materials-based gas sensors has created a new avenue of effective detection of toxic vapors at room temperature. These sensors have the potential to detect the formalin evaporated from adulterated food products.
Nanomaterials and Nanoelectronics Laboratory, headed by Dr. Hemen Kr. Kalita, Assistant Professor, Department of Physics, Guwahati University, Assam has developed this new technology.
Graphene oxide (GO), the oxidized form of graphene, exhibits high solution processability and ease of chemical modification with other materials such as metals, metal oxides, or polymers.
