Dissipation, residues and dietary risk assessment of dinotefuran in rice

In order to evaluate the residue behavior and dietary intake risk of the dinotefuran applied to rice, the residual trial of dinotefuran in rice were carried out in Anhui, Chongqing and Guangxi in 2012 and 2013, respectively. A novel method for the residue determination of dinotefuran in rice, rice hull and rice straw was developed by using high performance liquid chromatography with ultraviolet detector (HPLC-UV). The dietary risk assessment to different populations based on data of dinotefuran residues in rice was investigated. The samples were extracted by acetonitrile, purified by florisil chromatographic column, detected by HPLC-UV. Results showed that:The limits of quantification (LOQs) in rice, rice hull and rice straw were 0.05 mg/kg. At fortified levels of 0.05 to 2 mg/kg, the average recoveries varied from 70% to100% with the relative standard deviation of 0.5% to 6.5%. The results indicated that the dissipation of dinotefuran in rice straw fitted to the first order kinetics with half-lives varied from 2.3 to 4.8 days. Terminal residues in rice were less than 0.53 mg/kg at the 7th days after the last application, which was below the MRL of Japan (2 mg/kg) and CAC (8 mg/kg). The national estimated daily intake (NEDI) was between 0.438-1.087 μg/(kg bw·d) and the risk quotients (RQ) were between 0.002-0.005 for different populations in China, which indicated its low risk in rice.