Konda Lívia N, Füleky György, Morovján György
Institute for Veterinary Medicinal Products, 8 Szállás Street, H-1107 Budapest, Hungary.
J Agric Food Chem. 2002 Apr 10;50(8):2338-43. doi: 10.1021/jf011492h.
We evaluated the feasibility of extracting organic pesticides in soil using a hot-water percolation apparatus at 105 degrees C and 120 kPa pressure. Efficiency of the method was assessed by extracting six selected pesticides (acetochlor, atrazine, diazinon, carbendazim, imidacloprid, and isoproturon) from previously equilibrated soil at 13.6-65.8 mg/kg concentration range. Studies were performed on brown forest soil with clay alluviation (Luvisol). The method developed was compared to the traditional batch equilibrium method in terms of desorbed amount of pesticides from soil and extraction time. Pesticides in the liquid phase from the batch sorption experiment and in the effluent from the hot-water percolation were quantified by high-performance liquid chromatography with UV detection. The results of the percolation experiment are in close correlation with those of the conventional soil testing method. Desorbed quantities by hot-water percolation were 85% acetochlor, 62% atrazine, 65% carbendazim, 44% diazinon, 95% imidacloprid, and 84% isoproturon, whereas using batch equilibrium method 101, 66, 64, 37, 81, and 90% were desorbed, expressed as the percentage of the adsorbed amount of pesticide on soil following equilibration. The average time for hot-water extraction was 3.45 min, in contrast to the 16 h time consumption of the traditional batch method. The effect of temperature on stability of selected compounds was also evaluated using pesticide-spiked sand without soil. Recoveries of analytes ranged between 84.6 and 91.1% with reproducibility of 7.9-10.2%, except for diazinon, for which recovery was 59.4% with 14.4% relative standard deviation since decomposition occurred at elevated temperature. The percolation process has been described by a first-order kinetic equation. The parameters calculated from the equation provide an opportunity to estimate the amount of compound available for desorption, the rate of desorption processes in the studied soil-pesticide-water system, and modeling the leaching process to obtain additional information on the environmental behavior of the examined pesticide.
我们评估了使用热水渗滤装置在105摄氏度和120千帕压力下从土壤中提取有机农药的可行性。通过从浓度范围为13.6 - 65.8毫克/千克的预先平衡的土壤中提取六种选定的农药（乙草胺、莠去津、二嗪农、多菌灵、吡虫啉和异丙隆）来评估该方法的效率。研究在有黏粒淀积的棕色森林土壤（淋溶土）上进行。将所开发的方法与传统的批量平衡法在农药从土壤中的解吸量和提取时间方面进行了比较。通过高效液相色谱 - 紫外检测对批量吸附实验液相中的农药以及热水渗滤流出物中的农药进行定量。渗滤实验结果与传统土壤检测方法的结果密切相关。热水渗滤的解吸量分别为：乙草胺85%、莠去津62%、多菌灵65%、二嗪农44%、吡虫啉95%、异丙隆84%；而使用批量平衡法时，解吸量分别为101%、66%、64%、37%、81%和90%，以平衡后土壤上吸附农药量的百分比表示。热水提取的平均时间为3.45分钟，相比之下传统批量法耗时16小时。还使用不含土壤的加标农药砂评估了温度对选定化合物稳定性的影响。除二嗪农外，分析物的回收率在84.6%至91.1%之间，重现性为7.9 - 10.2%，二嗪农由于在高温下发生分解，回收率为59.4%，相对标准偏差为14.4%。渗滤过程用一级动力学方程进行了描述。从该方程计算得到的参数提供了一个机会，可用于估计可供解吸的化合物量、所研究的土壤 - 农药 - 水体系中解吸过程的速率，以及对淋溶过程进行建模，以获取有关所检测农药环境行为的更多信息。
