Non-Invasive Formaldehyde Sensor Can Detect Formalin in Fish

December 27, 2023

GS Paper III Science and Technology

Context: A new low-cost sensor made up of metal oxide nanoparticles–reduced graphene oxide composite can detect formalin in fish at room temperature in a non-invasive way.

Scientists developed a sensor to detect formalin in fish

It is developed by the Nanomaterials and Nanoelectronics Laboratory of Guwahati University, Assam.
Source material: The formalin sensor uses tin oxide-reduced graphene oxide composite.
Process: Graphene Oxide (GO) was synthesized through a process called wet chemical approach and tin oxide-reduced graphene oxide composite (rGO- SnO2) was synthesized by hydrothermal route followed by calcination of the obtained product.
The sensor is tested for adulterated fish at lab scale and on fish available in the fish markets of the Guwahati region.
The research is supported by DST-PURSE (Promotion of University Research and Scientific Excellence).
The research was published in the journal ACS Appl. Nano Mater.

Formaldehyde

Formaldehyde (CH₂O) is a colourless, highly toxic, and flammable gas at room temperature.
Main uses:
- In producing fertilizer, paper, plywood, and some resins.
- As a food preservative.
- In glues and resins, dyes, and textiles, disinfectants, building materials, automobile parts, embalming, and laboratories.
- In household products, such as antiseptics, medicines, and cosmetics.
Exposure: Irritation of the skin, throat, lungs, and eyes. It is also carcinogenic.

Formalin in fish

It is a mixture of water and formaldehyde, which is usually used on freshly caught fishes to extend its shelf life and enhance its sensory attributes such as color.
Food Safety and Standards of India (FSSAI) regulations of 2011, has banned the use of formalin in food products.
Example: Kerala pathologist traces high level of formalin content in fish bought at home when she tested the sample.
A team of researchers from Nagaon College, Assam detected the presence of 15 per cent formalin in the consignment of fish imported from outside the state.
Health scare: It can cause conditions such as abdominal discomfort, vomiting, renal injury, etc.

Significance of the research

Present sensors: They are either electrochemical-based or colorimetric-based( Colorimetric sensors are a class of optical sensors that change their colour when influenced by external stimuli.)
- Both methods are invasive and expensive.
- Moreover, low-level and selective detection are two major issues with these sensors
New Sensor: It is seen as a breakthrough in the field of food adulteration and will open new avenues for the development of affordable formalin sensor devices.
- shows long-term stability with a low detection limit.
- Is comparatively cheap
- Non-invasive in nature
- Can detect the presence of Formalin at room temperatures.

Promotion of University Research and Scientific Excellence (PURSE)

It is a Flagship Infrastructure program of the Department of Science and Technology, exclusively for the University sector.
Objective:
- To provide support for nurturing the research ecosystem and strengthening the R&D base of the Universities in the country.
- There will be support to acquire research facilities, research manpower cost, acquiring research consumables, funds for travel, organizing workshops and conferences, contingencies and maintenance of the facilities.
Thrust focus areas are Manufacturing, Waste processing, Clean Energy, Water, Startup India and Atmanirbhar Bharat.