Creating a Water Test for Pesticides Using Glow-in-the-Dark Dots and Copper

Greg Howard
21st January, 2024

Creating a Water Test for Pesticides Using Glow-in-the-Dark Dots and Copper

Image Source: Natural Science News, 2024

In research aimed at environmental monitoring, scientists have developed a new method that uses the glow of certain tiny particles to detect pollutants. This method involves a type of nanotechnology made from aloe leaves, which are more commonly known for their use in skin care products. Aloe leaves provide a renewable source for these particles, known as nitrogen-doping carbon quantum dots (N-CQDs), which have been created using a simple cooking-like process called hydrothermal treatment. When excited with ultraviolet light, these N-CQDs emit a bright blue fluorescence. For comparison, the researchers also created similar particles using a compound called glutathione and copper, which instead give off a strong red glow. By mixing the blue-emitting N-CQDs with the red-emitting copper-based particles, scientists devised a sensing system that changes color from blue to red in the presence of a specific pesticide called nitenpyram. This color change is due to a decrease in the blue fluorescence intensity when nitenpyram is present, while the red fluorescence remains largely unchanged. The change in fluorescence is the result of two factors. First is the inner-filtering effect, where the pesticide absorbs some of the light that would otherwise cause the N-CQDs to glow. Second, there is a static-quenching interaction, essentially a reaction between the pesticide and the N-CQDs that further decreases the blue glow. The efficiency of this color-changing system was quantified using a measure called the Stern-Volmer constant and it was shown that the reaction is influenced by the concentration of the pesticide. There’s a direct, linear relationship between the ratio of red to blue light intensity and the amount of nitenpyram in a sample, detectable from very low levels, which could be significant for environmental safety checks. The researchers validated the accuracy of their new method by testing real water samples and comparing the results with a widely used, but more complex, laboratory-based testing method involving liquid chromatography and mass spectrometry. The recovery rates for the new sensor fell within the range of 95.0% to 107.0%, showing it matches well with the established technique. This color-changing glow offers a compelling tool for on-site environmental monitoring without the need for expensive and complex lab equipment. It could provide an accessible, affordable, and adaptable means for routine assessment of nitenpyram pollution in outdoor settings.



Main Study

1) A dual-emitting fluoroprobe fabricated by aloe leaf-based N-doped carbon quantum dots and copper nanoclusters for nitenpyram detection in waters by virtue of inner filter effect and static quenching principles.

Published 8th February, 2024 (future Journal edition)

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