不同环境条件杂环农药三维荧光光谱发射特性研究

掌握不同环境因素下的光谱发射特性是农药准确测量的前提。以多菌灵、西维因、麦穗宁三种杂环农药为研究对象，研究了农药在不同pH值和常见阴、阳离子条件下的三维荧光光谱发射特性，并初步分析了Fe3+和Cu2+对三种农药的荧光猝灭机制。结果表明，多菌灵和麦穗宁均具有两个荧光峰，西维因仅有一个荧光区域，三种农药的主要荧光峰分别位于λ_ex/λ_em=280/300，310/340和280/335 nm，多菌灵和麦穗宁的次荧光峰Peak B分别位于λ_ex/λ_em=245/305 nm，λ_ex/λ_em=250/340 nm;多菌灵与麦穗宁随pH值变化表现为相似的荧光发射特征，在酸性/碱性降低时，荧光强度增大;酸性条件下西维因的荧光发射强度无明显变化，但在碱性条件下，随pH值的减小荧光强度不断增强;三种农药在pH值6.16～7.4范围内均可获得较好的荧光发射特征。水中CO2-₃，SO2-₄，NO-₃，Cl-，HPO2-₄，HCO-₃，Mg2+，Zn2+，NH+₄，Na+，Ca2+和K+等12种常见离子对多菌灵，西维因和麦穗宁的荧光发射特性无明显影响。Fe3+与Cu2+离子通过静态荧光猝灭反应, 影响三种农药的荧光发射强度。随着离子浓度的增加荧光强度不断降低，在实际测量中，需重点考虑Fe3+和Cu2+对测量结果的影响。该研究结果为水体杂环农药的准确测量提供了基础数据。

Study on Three-Dimensional Fluorescence Spectral Characteristics of Heterocyclic Pesticides in Different Environmental Conditions

The impact analysis of different environments on the fluorescence emission spectrum of pesticides is critical in detecting the concentration of pesticides .In this paper,three kinds of pesticides,carbendazim,carbaryl and fuberidazole,were selected as the research objects .Under different environment,such a s different pH values and the presence of different common anion or cation,three-dimensional fluorescence spectral emission (EEM) characteristic of pesticide s were analyzed .The experimental results showed that the primary fluorescence peaks for three kinds of pesticides were at λex/λem=280/300,310/340 and 280/335 nm (respectively); Carbendazim and fuberidazole had a se condary peak at 245/305 nm (PeakB) and 250/340 nm (PeakB) .We can come to the conclusion that with the change of pH value,the characteristic of fluorescence emission of carbendazim and fuberidazole is similar .We can find that the fluorescence intensities of carbendazim and fuberidazole were enhanced with the declining of the solution acidity or alkalinity and the fluorescence intensity of carbaryl had not changed with the declining of the solution acidity,but it increased with the declining of the solution alkalinity; the fluorescence emission spectra of the three kinds of pesticides had good fluorescence characteristics with the scope of the pH varying from 616 to 74 .Twelve common ions in water (CO2-3,SO2-4,NO-3,Cl-,HPO2-4,HCO-3,Mg2+,Zn2+,NH+4,Na+,Ca2+,K+) had no significant effect on fluorescence emission characteristics of carbendazim and fuberidazole .The fluorescence intensities were seriously influenced by Fe3+ and Cu2+ .The results showed that the pesticides fluorescence intensities were decreased with the ion concentration increasing .It was necessary to consider the quenching effects on pesticides of Fe3+ and Cu2+for the analytic results .The obtained results provided the basic research for improving the accuracy of the heterocyclic pesticides measurement in water .