Development of ultrasonic assisted extraction and salting out liquid-liquid extraction techniques for agricultural environmental monitoring of pyroxasulfone and dietary risk assessment

Abstract

The optimization of extraction methods for monitoring herbicide residues is crucial for ensuring food safety and environmental sustainability. The present study focuses on optimizing ultrasound-assisted extraction (UAE) and salting out liquid-liquid extraction (SALLE) techniques for the efficient extraction of pyroxasulfone from soil, wheat and water. Various factors such as solvent type and volume, ultrasonication time and temperature, extraction cycle, sample-to-solvent ratio, salt type and its concentration were optimized to achieve the highest extraction efficiency. A mathematical model was constructed using the Box-Behnken design to represent the relationship between the variables and the response (percent recovery). The developed method demonstrated high accuracy and precision for determining pyroxasulfone in soil, wheat and water with mean percent recoveries ranging from 81.6 to 100.2 % and relative standard deviation < 10 %. Degradation studies revealed that at the time of harvest, pyroxasulfone residues in both soil and wheat grain were below detectable limits (<0.01 µg g⁻¹), indicating effective degradation and minimal risk of residual contamination. HQ for pyroxasulfone was 0.113 indicating that there is no dietary risk associated with the consumption of rice containing pyroxasulfone residues. Additionally, environmental sustainability assessments using AGREE and GAPI metrics indicated the methods are green, offering low environmental impact and high efficiency. These findings underline the practical applicability of optimized UAE and SALLE techniques for pyroxasulfone residue analysis in agricultural environments, emphasizing their potential for routine monitoring and compliance with food safety standards.