利用光谱法研究泥炭腐植酸与吡唑草胺相互作用

Studying of the Interaction Between Peat Humic Acids and Metazachlor Using Spectroscopy Methods

采用光谱法分析了从泥炭土中分离出的腐植酸(HA)与吡唑草胺的相互作用。选择波兰南部和北部的5块泥炭地为研究对象。按照国际腐殖质学会推荐的程序提取腐植酸(HA1、HA2、HA3、HA4和HA5)。本研究使用的是以吡唑草胺为生物活性物质的吡唑草胺悬浮液浓缩物,即吡唑草胺500 SC。根据其元素组成对HA进行了评估。利用紫外-可见光分光光度计、动态光散射和延迟发光(DL)等光谱技术研究了HA结构及其与吡唑草胺的相互作用。根据国际土壤分类系统的标准(2015),基于其形态和化学性质,研究的泥炭土可分为以下几类:(1)强分解的高腐有机土;(2)较强分解的高腐有机土;(3)中分解的半腐有机土;(4)较弱分解的半腐半纤维有机土;(5)弱分解的纤维有机土。通过E_(4/6)系数测定的结果显示,HA2样品的粒径最大,HA3样品的粒径最小。在HA溶液中加入吡唑草胺后,E_(4/6)系数降低了33%~72%,水动力直径降低了4%~32%,加入吡唑草胺的不同HA样品的E_(4/6)系数之间无显著差异。在加入除草剂后,在蓝光和红光的刺激下,HA2样品的DL强度变化最大,粒径最大,氧含量和CQ值最高,芳构化率最低。因此,用E_(4/6)系数测定的HA分子粒径对于相同比例测定的HA-除草剂体系粒径没有影响。DL具有简单、快速、灵敏等优点,具有一定的应用价值,且与化学方法相比,结果误差较小。该方法可以提供HA的结构和性质以及它们的光反应性的信息。将DL技术应用于HA-除草剂相互作用的研究,有助于我们更好地理解HA的发光特性。

The analysis covered the interaction of humic acids (HA) isolated from peats with the metazachlor using spectroscopic methods.Five peatlands have been selected for the study in the southern and northern parts of Poland.Extraction of humic acids (HA1,HA2,HA3,HA4,and HA5) was performed using a procedure recommended by the International Humic Substances Society.Metazachlor 500 SC with metazachlor as a biologically active substance[2-chloro-N-(pyrazol-1-ylmethyl) acet-2’,6’-xylidide]has been used.HA have been assessed on the basis of their elemental composition.Spectroscopic techniques have been used to study the HA structure and their interaction with metazachlor including:UV-visible spectroscopy,dynamic light scattering,and delayed luminescence (DL).Based on their morphological and chemical properties,the studied peat soils can be classified as follows:(1) Eutric Murshic Sapric Histosols,(2) Eutric Sapric Histosols,(3) Eutric Hemic Histosols,(4) Eutric Fibric Histosols,and (5) Dystric Dranic Hemic Histosols according to the WRB guidelines (2015).Results showed that the largest particle size,measured by E_(4/6)coefficient,was found in HA2 sample,while the smallest in HA3 sample.The addition of metazachlor to HA solutions reduced the values of E_(4/6)coefficient by 33 to 72%,while the values of hydrodynamic diameter by 4 to 32%.No significant changes were found between E_(4/6)after adding of metazachlor to HA solutions.The largest changes in DL intensity,excited both by blue and red light after herbicide addition,were observed in HA2 sample,which is characterized by the largest particle size,the highest oxygen content and CQ value as well as the lowest “aromatization rate” value.The particle sizes of HA molecules measured by E_(4/6)coefficient do not impact on the particle sizes of HA-herbicide systems measured by the same ratio.The delayed luminescence may become valuable,because it is simple,fast,and sensitive.Additionally,the results show minor errors comparing with chemical methods.This method may provide information about structure and nature of humic acids,as well as their photo reactivity.The using of delayed luminescence in studies of HA-pesticides interaction may enable us to better understand the luminescence properties of HA.