Residual Dynamics and Safety Assessment of Imazalil, Prochloraz and Their Metabolites During Fresh-keeping Storage of Litchi

In order to evaluate the dietary risk of imazalil and prochloraz residues in whole fruit, peel and pulp of litchi, this study reported a gas chromatography-tandem mass spectrometry (GC-MS/MS) to determine the residue of imazalil, prochloraz and their metabolites simultaneously. The limit of detection and limit of quantitation of this method were 2.0 and 6.0 µg/kg for imazalil, 3.0 and 10.0 µg/kg for prochloraz, 6.0 and 20.0 µg/kg for imidazole ethanol, as well as 0.3 and 1.0 µg/kg for 2,4,6-trichlorophenol, respectively. The average recoveries in whole fruit, peel and pulp of litchi were 78.9%~107%. The relative standard deviation (RSD) ranges from 2.6% to 5.8%. The results of preservation showed that the higher the concentration of imazalil and prochloraz the higher the residual amount. The residue gradually migrated from peel to pulp with the increases in storage time. After freshness processing, the residues of imazalil and prochloraz in whole fruit and peel decreased, while the pulp increased to the maximum value on the 7th day, and then gradually decreased. Imidazole ethanol and 2,4,6-trichlorophenol increased with the increase of storage time. The risk of chronic and acute dietary intake within 14 days of safe interval was within acceptable range.