Residue Dynamics of Tebuconazole in Apple and Soil

Residue dynamics and final residue of tebuconazole in apple and soil were studied by HPLC. Residues of tebuconazole were extracted from apple and soil with menthol, concentrated and determined by HPLC with UV detector. The lowest detection limit of instrument for tebuconazole was 4.0×10-11 g. The limit of quantification was 0.002 mg/kg for apple and soil. The average recovery was 85.6 to 102.2%, and coefficient of variation was 2.85 to 9.47%, respectively. The results showed that half-life of tebuconazole in apple and soil were 10.8 to 12.5 days and 9.2 to 16.4 days, respectively. The fungicide of tebuconazole was applied as foliage spray according to the recommended dosage and the twice-recommended dosage, the final residue ranged from 0.058 to 0.230 mg/kg in apple, 0.109 to 1.371 mg/kg in soil, respectively. It did not exceed maximum residue limit 0.5 mg/kg established by EU in apple. According to the results, we recommend that 43% Folicur SC was applied as foliage spray three times at a dosage of 3 000 dilution factor for apple with a safe interval of 28 days from harvest.