差分吸收光谱-高斯拟合法研究富里酸质子化
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摘要：利用紫外-可见吸收光谱差分法结合高斯多峰拟合法研究了土壤富里酸在水溶液中的质子化特性.在 pH 3.0~11.0 范围内,富里酸差 分 吸 收 光 谱 在 235,320,280,360nm 处 出 现 特 征 波 峰 , 并 拟 合 得 到 6 类 高 斯 峰 (R2>0.983):A0(211.19nm) 、 A1[(238.62±1.13)nm] 、 A2 [(274.78±1.50)nm], A3 [(308.31±3.74)nm], A4 [(353.72±3.67)nm], A5 [(419.44±1.64)nm]和 A6 [(389.82±2.57)nm].高斯峰 A1~A6 位置和宽度 变化程度分别为 3.18~10.50nm(σ=1.13~3.74nm)和 3.36~19.08nm (σ=1.33~9.54nm).高斯峰 A1、A2、A5 和 A6 位置受 pH 值影响的变化程度 (3.18~5.50nm)小于高斯峰 A3 和 A4 位置变化程度(10.50~10.13nm);高斯峰 A1 和 A2 宽度受 pH 值影响的变化程度(3.36~8.49nm)小于高斯 峰 A3~A6 宽度变化程度(10.86~19.08nm).高斯峰 A1~A3 分别与酚羟基、羧基和酚羟基发色团有关;高斯峰 A4~A6 与分子构型构象的变化 有关,受分子电荷转移和发色团相互作用的影响.差分吸收光谱的特征波峰的差分吸光度∆A(235)、∆A(280)、∆A(320)和∆A(360)与 pH 值均 存在显著性正相关关系(R2=0.855~0.995).ln∆A(360)可用来反映高斯峰 A4 随 pH 值的变化情况(R2=0.938).结果表明,差分吸收光谱法可用于 研究水体中痕量富里酸质子化特性,为探究溶解性有机质与环境污染物之间的结合机理提供依据. 关键词：富里酸；质子化；差分吸收光谱；高斯峰 中图分类号：X703.1 文献标识码：A 文章编号：1000-6923(2017)12-4571-07
中国环境科学 2017,37(12)：4571~4577
China Environmewenku.baidu.comtal Science
差分吸收光谱-高斯拟合法研究富里酸质子化
宋凡浩 1,吴丰昌 1,冯伟莹 1,王国静 1,陈 曲 2,喻文强 1,3,雷啟焘 1,白英臣 1* (1.中国环境科学研究院,环境
基准与风险评估国家重点实验室,北京 100012；2.中国海洋大学,海洋化学理论与工程技术教育部重点实验室,山东 青岛 266100；3.南昌大学资源环境与化工学院,江西 南昌 330031)
Study on protonation of fulvic acid using differential absorption spectroscopy coupled with Gaussian fitting method. SONG Fan-hao1, WU Feng-chang1, FENG Wei-ying1, WANG Guo-jing1, CHEN Qu2, YU Wen-qiang1,3, LEI Qi-tao1, BAI Ying-chen1* (1.State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China；2.Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Qingdao 266100, China；3.School of Resources Environment and Chemical Engineering, Nanchang university, Nanchang 330031, China). China Environmental Science, 2017,37(12)：4571~4577 Abstract：The protonation properties of soil fulvic acid in aquatic systems were investigated using multi-peaks Gaussian fitting method based on UV-Vis differential absorption spectra. At the pH range of 3.0~11.0, the characteristic peaks were located at 235nm, 320nm, 280nm and 360nm in differential absorption spectra of SFA. Six Gaussian peaks were fitted from the differential absorption spectra of SFA (R2>0.983): A0 (211.19nm), A1 [(238.62±1.13) nm], A2 [(274.78±1.50) nm], A3 [(308.31±3.74) nm], A4 [(353.72±3.67) nm], A5 [(419.44±1.64) nm] and A6 [(389.82±2.57) nm]. The changes of the locations and widths of the Gaussian peaks A1~A6 ranged 3.18~10.50nm (σ=1.13~3.74nm) and 3.36~19.08nm (σ=1.33~9.54nm), respectively. The location changes of Gaussian peaks A1, A2, A5 and A6 (3.18~5.50nm), which were induced by the changes of pH, were less than that of Gaussian peaks A3 and A4 (10.50~10.13nm). Moreover, the width changes of Gaussian peaks A1and A2 (3.36~8.49nm), which were induced by the changes of pH, were less than that of Gaussian peaks A3~A6 (10.86~19.08nm). Gaussian peaks A1~A3were related to phenolic, carboxyl and phenolic chromophores, respectively. Gaussian peaks A4~A6 were associated with the changes in molecular conformation and affected by molecular charge transfer and internal reactions between chromophores. The differential absorbance of characteristic peaks, ∆A(235), ∆A(280), ∆A(320) and ∆A(360), in differential absorption spectra had significantly positive relationship with pH (R2=0.855~0.995). The ln∆A(360) in the study could be used to reflect the changes in
中国环境科学 2017,37(12)：4571~4577
China Environmewenku.baidu.comtal Science
差分吸收光谱-高斯拟合法研究富里酸质子化
宋凡浩 1,吴丰昌 1,冯伟莹 1,王国静 1,陈 曲 2,喻文强 1,3,雷啟焘 1,白英臣 1* (1.中国环境科学研究院,环境
基准与风险评估国家重点实验室,北京 100012；2.中国海洋大学,海洋化学理论与工程技术教育部重点实验室,山东 青岛 266100；3.南昌大学资源环境与化工学院,江西 南昌 330031)
Study on protonation of fulvic acid using differential absorption spectroscopy coupled with Gaussian fitting method. SONG Fan-hao1, WU Feng-chang1, FENG Wei-ying1, WANG Guo-jing1, CHEN Qu2, YU Wen-qiang1,3, LEI Qi-tao1, BAI Ying-chen1* (1.State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China；2.Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Qingdao 266100, China；3.School of Resources Environment and Chemical Engineering, Nanchang university, Nanchang 330031, China). China Environmental Science, 2017,37(12)：4571~4577 Abstract：The protonation properties of soil fulvic acid in aquatic systems were investigated using multi-peaks Gaussian fitting method based on UV-Vis differential absorption spectra. At the pH range of 3.0~11.0, the characteristic peaks were located at 235nm, 320nm, 280nm and 360nm in differential absorption spectra of SFA. Six Gaussian peaks were fitted from the differential absorption spectra of SFA (R2>0.983): A0 (211.19nm), A1 [(238.62±1.13) nm], A2 [(274.78±1.50) nm], A3 [(308.31±3.74) nm], A4 [(353.72±3.67) nm], A5 [(419.44±1.64) nm] and A6 [(389.82±2.57) nm]. The changes of the locations and widths of the Gaussian peaks A1~A6 ranged 3.18~10.50nm (σ=1.13~3.74nm) and 3.36~19.08nm (σ=1.33~9.54nm), respectively. The location changes of Gaussian peaks A1, A2, A5 and A6 (3.18~5.50nm), which were induced by the changes of pH, were less than that of Gaussian peaks A3 and A4 (10.50~10.13nm). Moreover, the width changes of Gaussian peaks A1and A2 (3.36~8.49nm), which were induced by the changes of pH, were less than that of Gaussian peaks A3~A6 (10.86~19.08nm). Gaussian peaks A1~A3were related to phenolic, carboxyl and phenolic chromophores, respectively. Gaussian peaks A4~A6 were associated with the changes in molecular conformation and affected by molecular charge transfer and internal reactions between chromophores. The differential absorbance of characteristic peaks, ∆A(235), ∆A(280), ∆A(320) and ∆A(360), in differential absorption spectra had significantly positive relationship with pH (R2=0.855~0.995). The ln∆A(360) in the study could be used to reflect the changes in