Effectiveness of dishwashing liquids in removing chlorothalonil and chlorpyrifos residues from cherry tomatoes

• Published in: Chemosphere (Oxford) Vol. 92; no. 8; pp. 1022 - 1028
• Main Authors: Wang, Zhiwei, Huang, Jiexun, Chen, Jinyuan, Li, Feili
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-08-2013; Elsevier
• Subjects: acetic acid; Biological and medical sciences; Cherry tomato; cherry tomatoes; China; chlorothalonil; Chlorothalonil (CHT); chlorpyrifos; Chlorpyrifos (CHP); Chlorpyrifos - analysis; Chlorpyrifos - chemistry; Chromatography, Gas; Detergent; detergents; Detergents - chemistry; Food industries; Food Safety - methods; Fruit and vegetable industries; fruits; Fundamental and applied biological sciences. Psychology; Fungicides, Industrial - analysis; Fungicides, Industrial - chemistry; Insecticides - analysis; Insecticides - chemistry; Lycopersicon esculentum - chemistry; markets; micelles; Nitriles - analysis; Nitriles - chemistry; pesticide residues; Pesticide Residues - analysis; Pesticide Residues - chemistry; soaking; sodium chloride; solubility; solubilization; temperature; washing; China; Detergent; Chlorothalonil (CHT); Cherry tomato; Chlorpyrifos (CHP); Chlorpyrifos; Removal; Insecticide; Nitrile; Pesticides; Washing; Dishwashing liquid; Fruit vegetable; Tomato; Fungicide; Chemical pollution; Decontamination; Residue; Chlorothalonil; Organophosphorus compounds; Performance
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2013.03.039

•Two detergents showed good pesticide removal ability in cherry tomatoes.•Removal of CHT and CHP was up to 80% and 42%, respectively, at 5gL−1 of detergent.•A duration of 20min was sufficient.•Adding 10% acetic acid or increasing washing temperature favored pesticide removal.
Washing is the most practical way to remove pesticide residues in fruits and vegetables. Two commonly used kitchen dishwashing liquids (detergents) in Chinese market were tested for enhanced removal of chlorpyrifos (CHP) and chlorothalonil (CHT) in cherry tomatoes by soaking the cherry tomatoes in the detergent solutions. The critical micelle concentrations of detergent A and detergent B were about 250mgL−1 and 444mgL−1, respectively. Detergent A had a higher solubilizing ability for pesticides and hence washing effectiveness than detergent B. The apparent solubility of CHP increased with increasing detergent concentration, while that of CHT remained comparatively invariant independent of detergent concentration within the tested range. The apparent solubility of CHP was also consistently higher in solutions of both detergents as compared to CHT. Due probably to its lower logKow value, CHT was more readily washed off cherry tomatoes than CHP. In terms of washing, a duration of 10–20min was sufficient for removal of pesticides on cherry tomatoes in distilled water and detergent solutions. The effectiveness of removing pesticides increased with increasing detergent concentration from 50mgL−1 to 5gL−1, with up to 80% CHT and 42% CHP removed. Multiple washing further increased pesticide removal. Adding 10% acetic acid to lower pH or increasing washing temperature favored pesticide removal, but 10% NaCl produced the shielding effect and substantially reduced the effectiveness of detergent A for pesticide removal.