Residue Dynamics of Myclobutanil in Cucumber and Soil

A method for the determination of myclobutanil residue in cucumber and soil by gas chromatography with ECD detector was established. The sample is extracted by acetonitrile, cleaned up by Florisil column. The average recovery of method varies from 84.0 to 106.4% and the relative standard deviation varies from 2.2 to 8.6%. When the sample was spiked at 0.05-5.0 mg/kg, the lowest detection limit for myclobutanil was 1×10-11 g, and detectable concentration was 0.010 mg/kg in cucumber. The results showed that the half-lives of myclobutanil in cucumber and soil were 2.5-2.7 days and 14.1-14.3 days, respectively. The final residues study revealed that the cucumber was sprayed at 5-6 times successively at the recommended dosages (60 g/ha), the residues in cucumber were below than 0.20 mg/kg after 5 days treatments.