Determination of Prochloraz Degradation Dynamics and Residues in Guavas by GC-MS

The guavas picked for a short time were soaked in prochloraz liquid,dried naturally,packaged by plastic bags for a single fruit,placed in room temperature for storage,and samples were mashed in certain times.Prochloraz was extracted from samples with acetonitrile,followed by cleanup in a layered analytical column packed with florisil,and eluted with acetonitrile and toluene(99:l,by vol)and was determined by GC-MS.The results showed that residue decline of prochloraz in guavas was found to conform to exponential equation.The half-lifes of prochloraz were 10.8-18.0 d;25 days later,decomposition rates of prochloraz reached 66.52-84.62%.The final residue results showed that 25 days storage at room temperature,soaked for two times,its prochloraz residues were 1.176 6-3.996 7 mg/kg; soaked for three times,its prochloraz residues were 2.104 6-4.510 3 mg/kg.