除虫脲在棉叶和土壤中消解动态分析及棉子中残留量膳食摄入评估

Dissipation dynamics analysis of diflubenzuron in cotton leaves and soil under field conditions and risk assessment for dietary residue intake

目的评价除虫脲在棉叶、土壤中的消解趋势和土壤及棉子中的残留水平。方法棉叶、土壤样品经乙腈提取、氯化钠盐析、弗罗里硅土固相萃取柱净化后,采用高效液相色谱-光电二极管阵列检测器检测;同时对2014年和2015年除虫脲在河南和北京两地棉叶及土壤中的残留消解动态进行分析并对棉子中的最终残留量进行膳食摄入评估。结果除虫脲在棉子、棉叶和土壤空白样品添加的平均回收率在79%~103%之间,相对标准偏差在3%~15%之间,最低检测浓度均为0.1 mg/kg。棉叶中除虫脲的残留消解半衰期在5.0~8.6 d之间,土壤中残留消解半衰期在3.8~14 d之间。按本试验方式进行施药及采样后,棉子中除虫脲的最终残留量低于0.1 mg/kg,土壤中的残留量低于0.19 mg/kg。结论除虫脲普通人群的国家估计每日摄入量是0.873229mg/kg·bw,占日允许摄入量的69.3%左右,认为对一般人群健康不会产生不可接受的风险。

Objective To evaluate the dissipation dynamics of diflubenzuron in cotton leaves and soil and the final residues of diflubenzuron in cotton seeds and soil.Methods Subsamples of the homogeneous cotton leaves and soil were extracted by acetonitrile,salted out by sodium chloride,cleaned up by a pre-activated florisil cartridge,and then analyzed by high performance liquid chromatography using photo-diode array（UPLC-PDA）.Meanwhile the dissipation dynamics of diflubenzuron in cotton leaves and soil from Henan and Beijing in 2014 and 2015 were analyzed,and risk assessment for dietary residue intake in cotton seeds was carried out.Results The recoveries spiked in blank cotton seeds,cotton leaves and soil were ranged from 79% to 103% with relative standard deviations（RSDs） of 3%～15%.The limits of quantification（LOQs） were 0.1 mg/kg for soil,cotton leaves and cotton seeds.The dissipation half-lives of diflubenzuron in cotton leaves and soil were 5.0～8.6 d and 3.8～14 d,respectively.The final residues at harvest in cotton seeds and soil were lower than 0.1 mg/kg and 0.19 mg/kg,respectively.Conclusion National estimates daily intake was 0.873229 mg/kg·bw,which accounted for 69.3% of daily intake approximately,so the potential health risk induced by diflubenzuron was not significant.