Nanomaterials and Nanoelectronics Laboratory, headed by Dr Hemen Kr. Kalita, Assistant Professor, Department of Physics, Gauhati University, Assam has developed a cost-effective formalin sensor that can effectively detect the presence of formalin in adulterated fishes.
According to the Ministry of Science & Technology, Government of India, the new low-cost sensor made of metal oxide nanoparticles–reduced graphene oxide composite can detect formalin adulteration in fishes at room temperature in a non-invasive way. The sensor shows long-term stability with a low detection limit.
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 that are expensive and invasive in nature. 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.
The sensor has been tested for adulterated fish at lab scale as well on fish available in the fish markets of the Guwahati region. The research for this supported by DST-PURSE (Promotion of University Research and Scientific Excellence) was published in the journal ACS Appl. Nano Mater. It was observed that the sensor could detect the presence of formalin in many fish sample units that are imported from regions outside the state of Assam. The crucial importance of this work is the non-invasive detection of formalin.
The designing of the prototype is in process in the lab which may be regarded as a breakthrough in the field of food adulteration. The prototype of this sensor will open new avenues for the development of affordable formalin sensor devices.
