Residues and dietary intake risk assessment of dithianon and pyraclostrobin in the jujube

The objective of this study was to investigate the dissipation dynamics, residue levels and the dietary intake risk of dithianon and pyraclostrobin in the jujube. Dithianon and pyraclostrobin in the jujube were determined by high performance liquid chromatography with ultraviolet detector. The samples were extracted by acetonitrile, and cleaned up by the florisil column. The dietary intake risk for different groups was estimated with%ADI and%ARfD. At the fortified level of 0.1 to 0.5 mg/kg, the recoveries of dithianon and pyraclostrobin ranged from 76% to 112% with the relative standard deviations of 1.1% to 9.6%. The limit of quantification(LOQ) of this method was 0.1 mg/kg. Dissipation dynamic of dithianon and pyraclostrobin in the jujube fitted the fist-order kinetics equation, with half-lives from 1.5 to 2.5 days and from 12.4 to 18.4 days, respectively. The terminal residues of dithianon and pyraclostrobin were from th day after the last application. The dietary intake risk was acceptable in all the other conditions. The security interval of 16% pyraclostrobin·dithianon water dispersible granules was 14 days, when sprayed for 3 times at the dose of 2.67 g/kg for the prevention of anthrax, and the dietary intake of various groups with less risk during the harvest season.