Field experiments were conducted to investigate the persistence of
diniconazole and etoxazole in broad bean pods, peels, seeds and soil. Samples were
taken after zero, 1, 3, 5, 7, 9, 14 and 21 days after pesticides application. The
diniconazole residue in plant samples was extracted by methanol, partition with
dichloromethane, cleaned up using coagulation solution, while the soil samples were
extracted with ethyl acetate. Estimation of diniconazole residues were performed by
(GLC- ECD). Etoxazole was extracted from plant samples with acetone, and from soil
samples using acetone: water (8: 2 v/v). The extract was partitioned with
dichloromethane and cleaned-up through a florisil column. Determination of etoxazole
residues were performed by HPLC-DAD. The recoveries of etoxazole and
diniconazole were in the range between 81–99 %. The results indicated that the half–
life values of diniconazole in pods, peels, seeds and soil were 2.46, 2.29, 5.25 and
5.56 days, respectively. While these values of etoxazole in pods, peels and soil were
2.27, 1.62 and 4.91 days, respectively. No residues of etoxazole could be detected in
seeds. Diniconazole residue was below the MRL in seeds. The pre-harvest interval
(PHI) of pods was in diniconazole application 9 days. And in case of etoxazole these
were 11 days. |
