Scientists at Saratov State University (SGU) have developed an express method for detecting residual imidazolinone herbicides in soil. According to RIA Novosti, the technology does not require laboratory equipment and can be used directly in the field. All that is needed is a plastic tablet, a UV lamp, and a smartphone camera.
The mechanism is two-stage. First, a soil sample is mixed with water, shaken, and allowed to settle. Then, a few drops of the solution are placed into a well on the tablet, which contains a protein with a molecular “fingerprint” complementary to the imidazolinone structure. The protein mechanically captures the herbicide molecules and holds them while the operator changes the water. After heating the tablet, the molecules are released back into the solution, where quantum dots are added – nanoparticles that glow green under UV light. The presence of the herbicide quenches the luminescence: the weaker the green signal, the higher the concentration of the toxin. To quantify, it is sufficient to measure the “greenness” with a smartphone camera.
The half-life of imidazolinones in soil ranges from 20 to 500 days, depending on the chemical composition and soil type, and extreme conditions – drought, waterlogging, changes in acidity – enhance their toxicity. These herbicides pose the greatest danger to crops planted after sunflowers. The proposed method provides farmers with a tool for the first time to quickly assess residual contamination before new sowing without sending samples to a stationary laboratory.