敌百虫在棉花和土壤中的残留研究

Study on Residue Dynamics of Trichlorphon in Cotton and Soil by HPLC-ESI/MS

建立了敌百虫在棉花和土壤中残留量的高效液相色谱-电喷雾质谱（HPLC-ESI／MS）测定方法。该方法最小检出量为1．5×10^-11g，最小检出浓度在植株和土壤中均为0．05mg／kg，加样回收率为植株71％～76％、土壤96％～103％、棉籽74％～79％，相对标准偏差分别为3．2％～16％、5．2％～12％、4．8％～6．5％。本法快速、灵敏、准确，可以用于敌百虫的残留分析。降解动态和最终残留研究结果表明，敌百虫在植株和土壤中的半衰期（T50）分别为0．4～0．6d和0．5～1．2d；以推荐剂量施药2～3次，或以2倍推荐剂量施药2～3次，采收间隔21d，棉籽和土壤中敌百虫残留量均低于0．05mg／kg。

An HPLC-ESI/MS method was established to determine residue dynamincs of trichlorphon in cotton plant, soil and seeds. Minimum determination quantity of the method was 1. 5 ×10^-11 g, and minimum determination concertration was 0.05 mg/kg for cotton plant, soil and seeds. Mean recoveries of cotton plant, soil and seeds obtained at fortification levels of 0.05～1.00 mg/kg were 71%～76%, 96%～103% and 74%～79%, with relative standard deviations （RSDs） of 3. 2%～16%, 5.2%～12% and 4.8%～6.5%, respectively. The HPLC-ESI/MS method allowed sensitive and selective quantification and identification at low levels in different matrices, and was applied to residue analysis of trichlorphon. The result showed that half-life of trichlorphon in cotton plant and soil as 0.4～0.6 days and 0.5～1.2 days. According to the recommended dosage and the twice-recommended dosage spraying 243 times, trichlorphon in cotton seeds and soil was not detected more than 0. 05 mg/kg while the interval to harvest was 21 days.