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
Molecular structure for Nitenpyram
Neonicotinoid insecticides are widely used in agriculture to protect crops from insect pests. However, their presence in the environment and potential impact on human health are growing concerns. These chemicals can persist in soil and water, and have been detected in human samples, raising questions about long-term exposure and potential health risks[2][3]. Traditional methods for detecting these compounds, like liquid chromatography coupled to tandem mass spectrometry, can be expensive and require specialized laboratory equipment, limiting their use for widespread monitoring. Researchers at Jiangsu & Wenzhou Universities have developed a new method for detecting nitenpyram, a common neonicotinoid insecticide, using a simple and cost-effective fluorescence-based technique[1]. This method utilizes specially created fluorescent materials derived from aloe vera leaves and copper nanoparticles. Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. The team created two types of fluorescent particles: nitrogen-doped carbon quantum dots (N-CQDs) from aloe vera leaves, which emit blue light, and glutathione-encapsulated copper nanoclusters (GSH-CuNCs), which emit red light. When these two are combined, they produce a solution that glows both blue and red. The key to the detection method lies in how nitenpyram interacts with the N-CQDs. When nitenpyram is present, it reduces the blue fluorescence of the N-CQDs, while the red fluorescence from the GSH-CuNCs remains relatively stable. This change in the ratio of blue to red light allows for the accurate measurement of nitenpyram concentration. This change is also visible to the naked eye, as the solution shifts from bright blue to dark red. The researchers found that the reduction in blue fluorescence is due to two main effects. The first is the “inner-filtering effect,” where nitenpyram absorbs some of the excitation light before it reaches the N-CQDs. The second is “static quenching,” where nitenpyram directly interacts with the N-CQDs, reducing their ability to fluoresce. The strength of this interaction, quantified by the Stern-Volmer constant, indicates a strong binding between nitenpyram and the N-CQDs. This new method is highly sensitive, capable of detecting nitenpyram concentrations as low as 0.15 micromolar (μM). It also provides accurate results in real-world water samples, with recovery rates comparable to traditional laboratory methods. Importantly, the technique is simple to operate, low-cost, and adaptable for on-site monitoring, making it a practical tool for routine environmental testing. Previous research has highlighted the widespread presence of neonicotinoids, including nitenpyram, in various environmental compartments and even in human hair[2]. This suggests potential exposure pathways through contaminated water, food, and direct contact. Studies have also shown that neonicotinoids can affect insect populations, including beneficial ones, and have demonstrated sublethal effects on organisms like fruit flies, impacting their development and metabolism[4][5]. The ability to quickly and accurately monitor nitenpyram levels in the environment, as offered by this new technique, is crucial for assessing potential risks and informing mitigation strategies. Furthermore, the use of aloe vera leaves as a source material for the N-CQDs is a significant advantage, as aloe is readily available throughout the year, unlike fruit pulps used in other similar methods. This accessibility contributes to the sustainability and cost-effectiveness of the technique.

EnvironmentBiochem

References

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)

https://doi.org/10.1016/j.aca.2023.342182

Related Studies

2) Residues of neonicotinoids in soil, water and people's hair: A case study from three agricultural regions of the Philippines.

https://doi.org/10.1016/j.scitotenv.2020.143822

3) Neonicotinoid insecticides and their metabolites: Specimens tested, analytical methods and exposure characteristics in humans.

https://doi.org/10.1016/j.jhazmat.2023.131728

4) Nitenpyram, Dinotefuran, and Thiamethoxam Used as Seed Treatments Act as Efficient Controls against Aphis gossypii via High Residues in Cotton Leaves.

Journal: Journal of agricultural and food chemistry, Issue: Vol 64, Issue 49, Dec 2016

5) Short exposure to nitenpyram pesticide induces effects on reproduction, development and metabolic gene expression profiles in Drosophila melanogaster (Diptera: Drosophilidae).

https://doi.org/10.1016/j.scitotenv.2021.150254


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