Liu W, Gan J, Papiernik S K, Yates S R
Soil Physics and Pesticide Research Unit, U.S. Salinity Laboratory, Agricultural Research Service, U.S. Department of Agriculture, 450 West Big Springs Road, Riverside, California 92507, USA.
J Agric Food Chem. 2000 Sep;48(9):4320-5. doi: 10.1021/jf990970+.
Adsorption of the chloroacetanilide herbicides acetochlor, alachlor, metolachlor, and propachlor was determined on soils and soil components, and their structural differences were used to explain their sorptivity orders. On all soils and soil humic acids, adsorption decreased in the order: metolachlor > acetochlor > propachlor > alachlor. On Ca(2+)-saturated montmorillonite, the order changed to metolachlor > acetochlor > alachlor > propachlor. FT-IR differential spectra of herbicide-clay or herbicide-humic acid-clay showed possible formation of hydrogen bonds and charge-transfer bonds between herbicides and adsorbents. The different substitutions and their spatial arrangement in the herbicide molecule were found to affect the relative sorptivity of these herbicides by influencing the reactivity of functional groups participating in these bond interactions. It was further suggested that structural characteristics of pesticides from the same class could be used to improve prediction of pesticide adsorption on soil.
测定了氯代乙酰苯胺类除草剂乙草胺、甲草胺、异丙甲草胺和敌稗在土壤及土壤组分上的吸附情况，并利用它们的结构差异来解释其吸附性顺序。在所有土壤和土壤腐殖酸上，吸附量按以下顺序降低：异丙甲草胺＞乙草胺＞敌稗＞甲草胺。在钙饱和蒙脱石上，顺序变为异丙甲草胺＞乙草胺＞甲草胺＞敌稗。除草剂-黏土或除草剂-腐殖酸-黏土的傅里叶变换红外光谱差谱表明，除草剂与吸附剂之间可能形成了氢键和电荷转移键。研究发现，除草剂分子中不同的取代基及其空间排列通过影响参与这些键相互作用的官能团的反应性，从而影响这些除草剂的相对吸附性。进一步表明，同一类农药的结构特征可用于改进对农药在土壤上吸附的预测。
