Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, School of Environment, Henan Normal University, Xinxiang, 453007, People's Republic of China.
Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of China, Nanjing, 210042, People's Republic of China.
Sci Rep. 2021 Nov 19;11(1):22613. doi: 10.1038/s41598-021-01016-9.
Hydrogen peroxide (HO) is ubiquitous in natural waters, and plays an important role in both biological and chemical processes. This study investigated the influence of dissolved organic matter (DOM) and its substituents on the accurate measurement of HO by peroxidase-mediated depletion of scopoletin fluorescence method which is one of the most widely used methods for the determination of low concentration HO in water. Six DOM and its 24 substituents interfered the determination of HO at environmentally relevant concentration of 200 nM with different levels except 2,6-dimethoxy-1,4-benzoquinone and benzoic acid, which may be associated with origin and types of DOM, and numbers and position of active functional groups in DOM constituents. Each substance concentration and the corresponding decreasing ratio to the measured HO concentration was fitted well to the linear model (R > 0.9), and the obtained interfering ratios (k, (mgC L)), expressing the degree of DOM or its substituents per unit concentration to the measurement of HO, were approximate for DOM, but the order of magnitude of k values of DOM constituents took on a large span from 10 to 10. When DOM levels exceed 0.1 mgC L or its substituent concentration is at nM level (low to 20 nM), the HO content will be underestimated substantially. A quantitative structure-activity relationship model with remarkable stability and strong predictability for the k of DOM substituents to HO measurement was established, and the k was related to the electron transfer capacity, hydrophobicity and stability of these compounds.
过氧化氢（HO）在天然水中普遍存在，在生物和化学过程中都起着重要作用。本研究调查了溶解有机物（DOM）及其取代物对过氧化物酶介导的 Scopoletin 荧光法（一种最广泛用于测定水中低浓度 HO 的方法）准确测量 HO 的影响。除了 2,6-二甲氧基-1,4-苯醌和苯甲酸外，六种 DOM 及其 24 种取代物在 200 nM 的环境相关浓度下以不同水平干扰 HO 的测定，这可能与 DOM 的来源和类型以及 DOM 成分中活性官能团的数量和位置有关。每种物质的浓度及其与实测 HO 浓度的相应降低比例与线性模型拟合良好（R>0.9），并获得了干扰比（k，（mgC L）），表示单位浓度的 DOM 或其取代物对 HO 测量的程度，近似于 DOM，但 DOM 成分的 k 值的数量级从 10 到 10 之间跨度很大。当 DOM 水平超过 0.1 mgC L 或其取代物浓度处于 nM 水平（低至 20 nM）时，HO 含量将被大大低估。建立了一种对 DOM 取代物对 HO 测量的 k 具有显著稳定性和强可预测性的定量构效关系模型，k 与这些化合物的电子转移能力、疏水性和稳定性有关。
