戊唑醇在水稻中的残留分析方法及消解动态

Residue Analysis and Degradation Dynamics of Tebuconazole in Rice

【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，FlorisiVb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0．05～5．0mg／kg时，平均回收率为88．80％一103．86％，相对标准偏差（RSD）为4．25％一14．36％。戊唑醇在糙米和土壤中的添加质量分数为0．02—2．0mg／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0．05mg，kg，在糙米和土壤中最低检测质量分数（LOQ）为0．02mg／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、3．14d；最后用药距收期21d时，戊唑醇在植株中的残留量为0．30mg／kg、稻壳中的残留量为0．22mg／kg、糙米中的残留量为〈0．02mg／kg、土壤中的残留量为〈0．02mg／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0．60～11．48d。

[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 aeetonitrile, 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 tebueonazole 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/kgwith 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.