柑橘果实贮藏期咪鲜胺和抑霉唑残留量的动态变化

用不同浓度的咪鲜胺及抑霉唑分别浸果处理柑橘果实,采用UPLC和气相色谱(gas chromatography,GC)检测咪鲜胺、抑霉唑在柑橘果实贮藏过程中的残留量。结果表明:咪鲜胺和抑霉唑在脐橙果皮中的残留量均高于椪柑果皮;咪鲜胺和抑霉唑在脐橙和椪柑果肉中的残留量均非常低。咪鲜胺在脐橙果皮中的降解趋势先慢后快,在椪柑果皮中的降解趋势则先快后慢;抑霉唑在椪柑果皮中的降解趋势与咪鲜胺在椪柑中的降解趋势类似。咪鲜胺(0.5、1.0、1.5mg/mL)和抑霉唑(0.5、1.0、1.5mg/mL)分别浸果2min后常温贮藏,柑橘全果中的残留量在整个贮藏期内均低于GB 2763-2014标准规定的5.00mg/kg最大残留限量(MRL)值,贮藏过程中柑橘可随时出库上市。

Dynamic analyses of prochloraz and imazalil residues in citrus during fruit storage

The extraction method for prochloraz and imazalil and the method for detecting imazalil was optimized.A improved method for detecting prochloraz with UPLC was established.Citrus fruits were dipped with different concentrations of prochloraz or imazalil according to the practice standards in production.The residues of prochloraz and imazalil in samples were detected by ultra-high performance liquid chromatography and gas chromatography,respectively.The results showed that prochloraz and imazalil residues of peel in Newhall navel orange were higher than those in Ponkan.The residues were very low in pulp.The trend of prochloraz degradation in Ponkan peel was from fast to slow,but trend of prochloraz degradation in Newhall navel orange peel was from slow to fast.The trend of imazalil degrada-tion was similar with that of Ponkan peel.According to GB 2763 -2014 standard,the maximum residue limits (MRL)of prochloraz and imazalil in whole citrus fruit is 5.00 mg/kg.After dipped with 0.5,1.0 or 1.5 mg/mL prochloraz or imazalil for 2 minutes,the residues of prochloraz and imazalil in whole fruit did not exceed the GB 2763-2014 standard during the whole storage period under room temperature.It is in-dicated that the citrus fruits are safety to be sold at all times.