Captan Residues In Apples And Soil Dynamics And The Final Residue Study

The analytical method for Captan residue in apple and soil has been established. The residue was extracted with acetone/dichlomethane mixture. After liquid-Liquid separation with petroleum ether, silica gel column was used for cleanup. Gas chromatography was employed for detection. The limit of determination was 0.006 mg/kg. The recovery ranged from 95.3% to 105.9% in whole fruit, from 99.0% to 104.5% in apple peal, from 98.2% to 104.3% in apple flesh, from 101.0% to 103. 8% in soil.The field experiments for Captan residue research was carried out in Tongchuan and Xingping country of Shanxi Province. The results indicated the degradation of Captan in apple, apple peal, apple flesh and soil. In 2000, the half life of Captan was 8.1 days in whole fruit of apple, 5.8 days in apple peal and 6.7 days in apple flesh in 2000. and the half life was 5.9 days in whole fruit of apple, 6.1 days in apple peal and 4.3 days in apple flesh in 2001. The half life of Captan in soil was 1.5 days in 2000 and 1.9 days in 2001.The results also indicated that, the residue of Captan was 3.10 to 18.76 mgt/kg in whole fruit, 3.29 to 41.42 mg/kg in apple peal, 0.037 to 0.260 mg/kg in apple flesh in 2000, and 1.92 to 20.61 mg/kg in whole fruit, 4.43 to 43.08 mg/kg in apple peal, 0.033 to 0.347 mg/kg in apple flesh in 2001, after 4 -8 times application, spraying 300 to 600 times diluent of 80% Captan WP, sampling from 12 to 34 days before harvest, and the residue of Captan in soil was not detectable in 2000 and 2001.The main metobolite of captan in soil was determined as phthalimide by GC/MS.