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首页> 外文期刊>Environmental Science & Technology >Application of Saturation Transfer Double Difference NMR to Elucidate the Mechanistic Interactions of Pesticides with Humic Acid
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Application of Saturation Transfer Double Difference NMR to Elucidate the Mechanistic Interactions of Pesticides with Humic Acid

机译：饱和转移双差核磁共振在阐明农药与腐殖酸相互作用中的应用

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摘要

Elucidation of mechanistic interactions of anthropogenic chemicals is critical to understanding and eventually predicting their behavior in the environment. Here, a recently developed technique, saturation transfer double difference (STDD) NMR spectroscopy is employed to determine the interactions of pesticides with humic acid (HA) at the molecular level. The degree of interaction at each NMR observable nucleus in the pesticide can be quantified in the form of an epitope map, which depicts the mechanism of the pesticide-HA interaction. Our results indicate that, at pH 7, halogen atoms (F and Cl) in water-soluble pesticides (diflufenzopyr, acifluorfen, and chlorsulfuron) play a dominant role in influencing binding to HA, whereas carboxyl groups likely play a secondary role when halogen atoms are also present in the molecule, as observed with diflufenzopyr and acifluorfen. However, when present on its own, the carboxyl group dominates in binding affinity to HA(e.g.,imazapyr). Electronegativity and electron density appear to play a key role in the mechanism of binding and results suggest that polar bonds are the primary points of HA contact in the water soluble pesticides investigated. Likely interactions may include hydrogen bonding and dipole—dipole interactions.
机译：阐明人为化学物质的机械相互作用对于理解并最终预测其在环境中的行为至关重要。在这里，最近开发的技术，饱和转移双差（STDD）NMR光谱用于确定农药与腐殖酸（HA）在分子水平上的相互作用。农药中每个NMR可观察到的核上的相互作用程度可以表位图的形式进行定量，该图描述了农药与HA相互作用的机理。我们的结果表明，在pH值为7时，水溶性农药（二氟苯并吡喃，环草胺和氯磺隆）中的卤素原子（F和Cl）在影响与HA的结合中起主要作用，而当卤素原子时，羧基可能起次要作用如双氟苯并吡喃和阿氟脲所观察到的，它们中也存在分子。然而，当羧基单独存在时，其羧基对HA（例如，咪唑并）具有结合亲和力。电负性和电子密度似乎在结合机理中起着关键作用，结果表明极性键是所研究的水溶性农药中HA接触的主要点。可能的相互作用可能包括氢键和偶极-偶极相互作用。

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