土壤中结合态苯氧羧酸类除草剂的测定

THE DETERMINATION OF BOUND RESIDUES OFCHLOROPHENOXY ACETIC HERBICIDES IN SOILS

利用超临界ＣＯ２流体萃取的方法提取２甲４氯(ＭＣＰＡ),２,４－Ｄ和除草醚在三种土壤中的结合残留．结果表明,在培养２００ｄ的时间内,ＭＣＰＡ的结合残留量为１．０ｌ－５．１２ｍｇ·ｋｇ－１,占添加总量的２．０－１０．１%;２,４－Ｄ的结合残留量为０．２４－２．６５ｍｇ·ｋｇ－１,占添加总量的０．５－５．３%;除草醚的结合残留量为６．５３－１９．３０ｍｇ·ｋｇ－１,占添加总邑的１２．９—３８．２%．农药结合态与游离态含量的比值随时间的延长而增加．

In this paper, we used the method of supercritical CO2 extraction to extract bound pesticide residues from three kinds of soils. The pesticides included MCPA, 2,4-D and nitrofen. Within 200 days of incubation time, the concentration of bound residue of MCPA was 1.01?.12 mg昸g-1 in soils which was 2.0?0.1% of the fortification level; the concentration of bound residue of 2,4-D was 0.24?.65 mg昸g-1 which was 0.5?.3% of the fortification level; nitro-fen was 6.53?9.30mg昸g-1 which was 12.9?8.2% of the fortification level. The ratios bet-ween bound residues and extractable residues of 2,4-D and nitrofen were increasing with time.