Residue Detection and Degradation of Tebuconazole in Cucumber and Soil

In order to know clear residue pollution and degradation trends of tebuconazole in cucumber and soil,an analytical method of HPLC was established for determining tebuconazole residue in cucumber and soil. The field experiments were conducted in Guangdong,Hubei and Shanxi. The result showed that the samples were extracted with acetonitrile,clean-up using a Florisil solid phase extraction cartridge,then determined by reversed phase HPLC equipped with UVD and quantified by external standard. At three spiking levels from 0. 01to 1. 0 mg /kg,the recoveries in cucumbers were 87. 32 %- 95. 11 %,with RSD 2. 79 %- 5. 90 %,and the recoveries in soil were 86.15 %- 92. 45 % with RSD 2. 64 %- 5. 17 %. Limit of detection was 2. 6 × 10- 2ng,and the lowest concentrations detected were 0. 01mg /kg in cucumber and soil. The degradation of tebuconazole in cucumber and soil could be described with equation: Ct= C0e- kt,and the half-life of tebuconazole turns was 3. 16- 4. 29 d in cucumber and 4. 50- 6. 09 d in soil. When cucumbers were treated 3- 4 times with low112. 50 g( ai) /hm2or high 168. 75 g( ai) /hm2dosage of tebuconazole,the residues in cucumbers with the last application after 2,3 and 5 d were under 1 mg /kg,which was safe according to the MRL( minimum required performance level) standard( 1 mg /kg) in cucumber from China.