On-site monitoring of atrazine in edible oils: Integrating reverse phase transfer extraction with lateral flow immunoassay for rapid screening

Background

Sample pretreatment is pivotal yet frequently overlooked in rapid biosensor development. Conventional extraction of lipophilic pesticides (e.g., atrazine) from edible oils relies on organic solvents and multistep procedures, which drastically limit detection speed. To address this limitation, this study developed a hazardous-solvent-free, single-step extraction method for atrazine in edible oils, coupled with lateral flow immunoassay strips for rapid detection.

Results

The study found that using a 10 mmol/L Tween-80 solution with an oil-to-water phase ratio of 1:2 (V/V) and an extraction time of 2 min yielded the highest extraction efficiency. The total pretreatment and detection time of this method was less than 15 min, with a limit of detection (LOD) of 0.096 μg/kg and a linear range of 0.32–72.9 μg/kg for atrazine in edible oils. The method demonstrated spiked recoveries of 83.61 %–120.00 %, and cross-reactivity with potential interfering substances (e.g., typical contaminants and additives in oils) was below 1.41 %. Further investigation into the extraction mechanism revealed that atrazine in the oil phase was extracted by aqueous Tween-80 micelles, and it was hypothesized that micelles with a dynamic light scattering (DLS) measured hydrodynamic diameter of approximately 35 nm likely played a predominant role.

Significance

In conclusion, this study established a green, simple, and rapid hazardous-solvent-free method for atrazine detection in edible oils. Furthermore, the mechanism of Tween-80-mediated atrazine extraction was investigated, proposing a novel theory of Reverse phase transfer extraction, which provides new insights for developing eco-friendly liquid-liquid extraction strategies for lipophilic contaminants.