Heterogeneous reactions of suspended parathion, malathion, and fenthion particles with NO₃ radicals

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• 作者：Changgeng Liu ; Bo Yang ; Jie Gan ; Yang Zhang ; Miao Liang ; Xi Shu ; Jinian Shu ; ^{jshu@rcees.ac.cn}
• 关键词：Organophosphorus pesticides ; Heterogeneous reaction ; NO3 radicals ; GC/MS ; Aerosol mass spectrometry
• 刊名：Chemosphere
• 出版年：2012
• 期刊代码：15_00456535
• 类别：env
• 出版时间：April, 2012
• 卷：87
• 期：5
• 页码：470-476
• 文件大小：658 K

摘要

Organophosphorus pesticides (OPPs) emit into the atmosphere in both gas and particulate phases via spray drift from treatments and post-application emission, but most of their degradations in the atmosphere are not well known. In this study, the heterogeneous reactions of nitrate (NO₃) radicals with three typical OPPs (parathion, malathion, and fenthion) absorbed on azelaic acid particles are investigated using an online vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The reaction products observed with the VUV-ATOFMS are identified on the basis of GC/MS analysis of the products in the reaction between NO₃ radicals and the coating of the pesticide. Paraoxon is identified as the only product of parathion; malaoxon and bis(1,2-bis-ethoxycarbonylethyl)disulfide as the products of malathion; fenoxon, fenoxon sulfoxide, fenthion sulfoxide, fenoxon sulfone, and fenthion sulfone as the products of fenthion. The degradation rates of parathion, malathion, and fenthion under the experimental conditions are 5.5 脳 10^鈭?, 5.6 脳 10^鈭?, and 3.3 脳 10^鈭? s^鈭?, respectively. The pathways of the heterogeneous reactions between the three OPPs and NO₃ radicals are proposed. The experimental results reveal the possible transformations of these OPPs through the oxidation of NO₃ radicals in the atmosphere.