A newly developed, low-cost sensor can detect and accurately measure the amount of the widely used and controversial herbicide, glyphosate, in droplets of liquid in a laboratory test. Ultimately, that is the goal for this sensor: to test human samples for monitoring glyphosate exposure, but in the study published in Biosensors and Bioelectronics, researchers first showed the sensor’s potential for testing beverages.
Before this new development,methods of detecting and measuring herbicides like glyphosate often relied on meticulous preparation of samples and expensive scientific equipment like mass spectrometers. Other methods involve using biological antibodies to attract and bind the herbicide molecules, which is also expensive with materials that need to be carefully stored to prevent degradation of the natural components.
The sensor developed by the research team uses electrically conducting polymer nanotubes that are imprinted with molecule-sized cavities that can bind glyphosate molecules—essentially mimicking the biological antibodies. These nanotubes are then coated on a 3-D-printed sensor device that uses an electric current to quantify the glyphosate concentration. Because it uses an artificial antibody instead of biological one, the sensor doesn’t need special storage, and the sensing materials are relatively inexpensive.
The researchers tested the sensor on samples of orange juice and rice beverages that they spiked with known levels of glyphosate. They found the sensor had the ability to detect the herbicide with high sensitivity and specificity. Glyphosate has been approved for use by many regulatory agencies including the U.S. Environmental Protection Agency, which issued a statement in 2020 that it is safe for use at recommended levels. Yet, some groups and studies have raised concerns about glyphosate’s health and environmental risks, and the World Health Organization’s International Agency for Research on Cancer has classified it as “probably carcinogenic to humans.
Shichao Ding et al, Molecularly imprinted polypyrrole nanotubes based electrochemical sensor for glyphosate detection, Biosensors and Bioelectronics (2021). DOI: 10.1016/j.bios.2021.113434