Detecting Herbicides Using Carbon Dots

Researchers from Assam have created carbon dots from the weed – water hyacinth – to detect the herbicide – pretilachlor.

The researchers, while trying to find ways to turn the weed water hyacinth into a value-added-product, they have struck upon the idea of using it for detecting the herbicide pretilachlor.
Water hyacinth is found in water bodies, and in Assam, almost all water bodies are infested with the weed.
For this purpose, the research team has produced carbon nanoparticles from the weed.
The nanoparticles were selective and are sensitive to the herbicide.

To make the carbon nanoparticles called the carbon dots, the researchers harvested water hyacinth leaves, removed the chlorophyll, dried and powdered the leaves.
After undergoing several treatments the powder is converted into carbon dots.
A nanoparticle which is less than 10 nanometre is called a dot or nanodot.
The carbon dots created by the research team gave green fluorescence under UV light.
This is due to a small oxygen functional groups on the surface of the dot.
The team studied the herbicide pretilachlor mixed in water and carbon dots using special equipment.
In the presence of pretilachlor, the fluorescence intensity of the carbon dots increased.
While the team tested the carbon dots with other herbicides, they found that the dots were extremely sensitive to pretilachlor and could detect even small traces of the herbicide.
After studying the effectiveness of the carbon dots in the lab, the team collected soil samples across the state and tested for pretilachlor.
The team also described how the electron transfer happens between the dot and the herbicide that is enabling florescence enhancement.
The team is of the view that their model will be a viable alternative to expensive sensors available in the market to detect herbicide contamination.