Reduction of Imidacloprid on strawberry using combined plasma-activated water and ultrasound treatment: efficacy and mechanisms.

This study examined the reduction of Imidacloprid (IMD) residues in aqueous solutions and on strawberry surfaces using plasma-activated water (PAW), ultrasound (US), and their combination (PAW-US). PAW alone achieved 94.8 % reduction in solution and 61.6 % on strawberries. US had minimal effect on IMD degradation in solution but enhanced pesticide removal from strawberry surfaces, achieving 90.2 % degradation with PAW-US. High-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) identified key degradation products and pathways, including hydroxylation, oxidation, and cleavage of the imidazolidine ring with PAW and PAW-US generating similar degradation products. PAW-US facilitated greater pesticide interaction with reactive oxygen and nitrogen species, improving pesticide reduction without affecting strawberry quality. Toxicity analysis using ECOSAR software confirmed that IMD degradation products exhibited lower acute and chronic toxicity than the parent compound. These results suggest PAW-US as an effective, eco-friendly alternative for pesticide residue removal in fresh produce.