A technology, intended to detect pesticide residues on fruits and vegetables is currently being developed by researchers from ITMO University (Russia), the National University of Singapore, and the University of Rovira i Virgili (Spain). It is described in a paper that was recently published in the journal Nanoscale.
According to an article on newatlas.com, the process involves combining silver nitrate and the organic compound melamine, then adding the mixture to a Petri dish containing a base layer of agar gel. The silver nitrate reacts with the other ingredients, forming crystals. After exposure to light, these decompose to form silver nanoparticles.
Everything is then dried, forming a light and flexible film. When that film is placed on a piece of fruit and wetted with alcohol, the melamine draws in any pesticide molecules that are present on the fruit's skin.
Supermarket employees can then check the manner in which light is reflected by the silver nanoparticles in the film, utilizing a handheld optical spectrometer.
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