New way to detect dangerous pesticides with a novel nanozyme

By Dr. Tim Sandle
Published January 20, 2022

Blood specimen tubes are seen in the laboratory of Bellville Medical Center in the state of Texas where hospitals are overwhelmed due to record Covid-19 hospitalizations. — © AFP

Propagating the growth of crops using pesticides have become common in modern agriculture. While this process can address certain diseases, the side effects can pose risks and there is evidence that a lack of controls around pesticide use is affecting human health and the ecosystem’s balance.

Such pesticides like organophosphorus (organic compounds containing phosphorus) pose risks to the food chain and to the whole eco-system. In more concentrated forms this class of pesticides can be used as nerve agents.

To address this, assessing pesticide concentrations requires constant monitoring. To help advance this process a recently published a study on Journal of Pharmaceutical Analysis highlights the development of a sensitive electrochemical detection method.

This Chinese-developed method is based on bifunctional cerium oxide nanozyme to identify organophosphate pesticides in plants in the near future. The research study has focused on the detection of methyl-paraoxon (a class of organophosphate insecticides) in plant extracts. These chemicals are commonly used as pest repellents for crops like cotton and legumes.

According to lead researcher Dr. Li: “Under the optimized conditions, we achieved desirable recoveries for different herbal samples using cerium oxide nanozyme. We believe that our electrochemical method can be practically applied in the rapid detection of pesticide residues.”

Through an iterative research process, the cerium oxide nanozyme modified glassy carbon electrode was prepared to improve the sensitivity. The developed method was applied in three herbal plant samples (the herbs were: Coix lacryma-jobi (common name Job’s tears); Adenophora stricta (known as ladybells) and Semen nelumbinis (used in treatment of depression in many Asian countries)).

These studies showed that under the optimum conditions, the method could provide a linear range from 0.1 to 100 μmol/L for methyl-paraoxon with a detection limit of 0.06 μmol/L. This is of sufficient sensitivity to detect levels of the pesticide that would pose a risk to human health.

The research, once commercialized, should add to the pool of pesticide detection methods. The research has been published in the Journal of Pharmaceutical Analysis. The research paper is titled “Electrochemical detection of methyl-paraoxon based on bifunctional cerium oxide nanozyme with catalytic activity and signal amplification effect.”