DISSIPATION AND RESIDUE OF METAMITRON IN SUGAR BEET AND THE SOIL OF CHINA

摘要

The dynamics of metamitron in soil and sugar beet were determined as well as the final residues in soil, sugar beet, and beet root. The average recoveries were 96.9-106.3%, 75-99.7% and 74.6-100.3% for soil, sugar beet plant and beet root, respectively. The relative standard deviations (RSDs) ranged from 2.3% to 6.1%. The limit of detection was 2.0×10~(-2)ng, and the limit of quantity was 0.02 mg/kg for all the samples. The results of dynamic experiment showed that the dissipation of metamitron in soil followed the first-order reaction. Metamitron in sugar plant disappeared very quickly and could not be detected (＜LOQ) at the 3-4 leaf stage. In the final residues experiment, although the metamitron could be still determined in soil, it was not detected in the sugar beet plant and roots. As can be inferred from the experimental results; 5.25 kg a.i. ha~(-1) was the recommendable dosage, and this could be used to set the maxmum residue limit (MRL) of metamitron in China.