戊唑醇在水稻中的残留分析方法及消解动态

目的]为检测水稻中戊唑醇残留及评价其在水稻上使用的安全性,建立了戊唑醇在水稻植株、稻壳、糙米和土壤中的残留分析方法。方法]水稻样品采用乙腈提取,Florisil小柱净化,GC-NPD测定。同时,于浙江、山东和湖南3地进行了田间试验。结果]戊唑醇在水稻植株和稻壳中的添加质量分数为0.05~5.0 mg/kg时,平均回收率为88.80%~103.86%,相对标准偏差(RSD)为4.25%~14.36%。戊唑醇在糙米和土壤中的添加质量分数为0.02~2.0 mg/kg时,平均回收率为89.19%~102.27%,相对标准偏差(RSD)为2.26%~8.58%。戊唑醇在水稻植株和稻壳的最低检测质量分数(LOQ)为0.05 mg/kg,在糙米和土壤中最低检测质量分数(LOQ)为0.02 mg/kg。田间试验表明:戊唑醇在水稻植株中的消解动态符合一级动力学方程,在浙江、山东和湖南3地水稻植株中的半衰期分别为0.60、11.48、3.14 d;最后用药距收期21 d时,戊唑醇在植株中的残留量为0.30 mg/kg、稻壳中的残留量为0.22 mg/kg、糙米中的残留量为<0.02 mg/kg、土壤中的残留量为<0.02 mg/kg。结论]该方法的灵敏度、精密度和回收率等均符合农药残留分析的要求。戊唑醇在水稻植株中属于易降解农药,降解半衰期为0.60~11.48 d。

Residue Analysis and Degradation Dynamics of Tebuconazole in Rice

Aims] The method for the determination of tebuconazole residues in rice plant,rice hull,rice and soil were estimated for evaluating the safety of tebuconazole in paddy field.Methods] The samples were extracted with acetonitrile,clean-up using a Florisil solid phase extraction cartridge,and subsequent determination by gc-NPD.And the field experiments were investigated in Zhejiang,Shandong and Hunan.Results] Average recoveries of tebuconazole in rice plant and rice hull were found in the range of 88.80-103.86% at the three spiking levels from 0.05 to 5.0 mg/kg with relative standard deviations of 4.25-14.36%.Average recoveries of tebuconazole in rice and soil were found in the range of 89.19-102.27% at the three spiking levels from 0.02 to 2.0 mg/kg with relative standard deviations of 2.26-8.58%.The limits of quantification(LOQ) in rice plant and rice hull were 0.05 mg/kg.The limits of quantification(LOQ) in rice and soil were 0.02 mg/kg.The field experiments demonstrated that the decline curves of tebuconazole in rice plant were accorded with the first-order kinetics equation,and the half-lives were 0.60 d in Zhejiang,11.48 d in shandong,and 3.14 d in hunan,respectively.The residue of tebuconazole was 0.30 mg/kg in rice plant,0.22 mg/kg in rice hull,<0.02 mg/kg in rice and <0.02 mg/kg in soil,respectively,after 21 d of spray.Conclusions] The method was suitable for the determination of tebuconazole residues in rice.Tebuconazole was easily degradable pesticides in rice plant,and the half-lives were 0.60-11.48 d.