摘要：This study was performed to investigate the ef- fect of ozonation treatment at different ozone con- centrations (0.5_._ 2 and 5) ppm for different periods of time (5, 10 and 15) minutes on reducing the per- centage of spiked rnyclobutanil of (2, 6 and 10) ppm on lettuce leaves using gas chromatography equipped with micro electron capture detector. The results showed that ozonation treatment at 0.5, 2 and 10 ppm significantly reduced the spiked 1nyc1obu- tanil concentration on lettuce, after 15 minutes of ozone treatment. The concentration of myclobutanil did not reach the allowed maximum residues limits in Codex Alimntarous and European regulations (0.05) ppm. The maximum reduction percentages af- ter 15 min of ozone treatment at 0.5 ppm were 87.48, 90.00 and 92.80% for spiked concentrations of my- clobutanil at 2, 6 and 10 ppm, respectively. On the other hand, the maximum reduction percentages af- ter ozone treatment for 15 min at 2 ppm were 90.55, 96.77 and 97.95% for spiked concentration of my- clobutanil at 2, 6 and 10 ppm, respectively. At last the maximum reduction percentages for 15 min at 5 ppm ozone concentration were 94.49, 98.30 and 99.00% for spiked concentrations of myclobutanil at 2, 6 and 10 ppm, respectively. Meanwhile, the reduc- tion percentages after soaking with tap water for 15 min were 17.56, 19.32 and 22.51% for 2, 6 and 10 ppm spiked myclobutanil concentrations on lettuce fruits. It was concluded from this research that ozone treatment has a significant effect on myclobulanil spiked concentration and it could be used as a method for reduction of this pesticide residues in fruits and vegetables. Ozone affected the pesticides residues concentration in a concentration—time de- pendent manner.
