A Green Colorimetric Nanosensor for the Detection of Hydrogen Peroxide in Milk

The development of a new, green colorimetric nanosensor is poised to improve the identification of hydrogen peroxide in milk, according to a recent study published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (1). Hydrogen peroxide is a toxic substance, so this nanosensor helps improve food safety and quality control of food products.

Ingestion of hydrogen peroxide can result in irritation to many parts of the body, including throat, nose, skin, and eyes (2). Increased exposure to hydrogen peroxide can be hazardous to human health (2). This compound is often used in various industries, including the food industry. Although food regulations normally prohibit the use of this chemical in food items, it is often illegally added to food products to increase their shelf life and prevent food waste (1). Many consumers are unaware of this practice, and therefore, it is important that food regulators have a way to detect hydrogen peroxide in food before it goes to market.

milk pouring into glass | Image Credit: © alter_photo - stock.adobe.com.

Recently, a team of researchers, led by Rajib Biswas of Tezpur University, explored this challenge. To try and improve on existing methods for detecting hydrogen peroxide in food, the researchers developed a green, rapid colorimetric nanosensor and tested its ability to identify hydrogen peroxide in milk and other dairy products.

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The team at Tezpur University formed the basis of the nanosensor using cotton leaves as a way to both reduce and functionalize agents for the synthesis of silver nanoparticles (AgNPs) (1). The research team then conducted characterization studies to confirm the successful synthesis of stable, spherical AgNPs with a plasmonic peak at approximately 434 nm and a size of around 16 nm (1). The techniques used to conduct these studies included UV-visible spectroscopy, X-ray diffraction (XRD), and electron microscopy. These functionalized nanoparticles demonstrated sensitivity to hydrogen peroxide, enabling the colorimetric detection of the compound in milk samples, both in liquid form and on paper substrates, with a low limit of detection (LOD) of 8.46 ppm, even in the presence of other interfering substances (1).

This method differs from and improves on traditional methods because it is eco-friendlier and more cost effective, the researchers said (1). By harnessing natural resources as reducing agents, the researchers have eliminated the need for complex and expensive synthesis processes, making the detection of hydrogen peroxide more accessible and efficient (1). Moreover, the use of bio-reducing agents has enhanced the stability of the nanoparticles, which prevented aggregation and ensured the reliability of the results (1).

When the method was validated, the nanosensor performed at a clip of 92%, along with a detection limit well below the permissible threshold set by regulatory bodies (1). The performance of this nanosensor signifies its potential for widespread adoption in quality control measures within the dairy industry, offering a simple yet powerful tool for identifying adulterants and ensuring consumer safety (1).

The reported method represents a significant advancement in biosensing technology, offering a greener, more sustainable approach to detecting hazardous chemicals in food products. Its simplicity and effectiveness underscore its suitability for real-world applications, promising a safer and more transparent food supply chain for consumers worldwide (1).

References

(1) Das, U.; Saikia, S.; Biswas, R. Highly Sensitive Biofunctionalized Nanostructures for Paper-based Colorimetric Sensing of Hydrogen Peroxide in Raw Milk. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2024, 316, 124290. DOI: 10.1016/j.saa.2024.124290

(2) Centers for Disease Control and Prevention, Hydrogen Peroxide. Available at: https://www.cdc.gov/niosh/topics/hydrogen-peroxide/default.html#:~:text=Hydrogen%20Peroxide%20(H%E2%82%82O%E2%82%82)%20is%20a,from%20exposure%20to%20hydrogen%20peroxide. (accessed 2024-05-07).