Horizontal infiltration experiments with a fluorescent dye (e.g., Na‐fluorescein) potentially allow the quantification of the macropore–matrix mass transfer of reactive solutes through coated macropore surfaces. The objectives were (a) to determine the movement and map the spatial mass distributions of a reactive and fluorescent dye (i.e., Na‐fluorescein) at the millimeter scale during horizontal tracer application to the intact structural surface of a soil aggregate, and (b) to validate the method by comparing total masses as quantified with Fluorescence imaging with total applied dye masses. For the quantification of dissolved masses of dye, millimeter‐scaled distributed water contents obtained from horizontal flow simulation using Hydrus‐1D were multiplied with mapped dye solution concentrations. The spatial distribution of dye concentrations was visualized and quantified with a fluorescence imaging technique at a pixel resolution length of ∼100 μm. Submillimeter‐scaled distribution maps of adsorbed dye concentrations were derived using the calibrated Freundlich adsorption model. The sorption isotherm predicted that most of the dye was adsorbed to soil. In total, 1,366 μg of dye was transferred through the coated matrix block, of which 1,181 μg was adsorbed to soil. The applicability of the method was validated by comparing applied and recovered Na‐fluorescein masses, which corresponded relatively closely. Although the test of the approach presented here was limited by uncertainties regarding the local distributions of water contents and bulk density, the method could be applied to map two‐dimensional horizontal distributions of dye in an intact soil clod for quantifying macropore–matrix mass transfer of the reactive solute.

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荧光成像定量分析的反应物溶质的大孔-基体传质

使用荧光染料（例如，Na-荧光素）的水平渗透实验可能允许量化反应性溶质通过涂层大孔表面的大孔-基质传质。目的是（a）在水平示踪剂施用于土壤团聚体的完整结构表面上的过程中，确定毫米级的活性染料和荧光染料（即，Na-荧光素）的运动并绘制空间质量分布图，以及（b ）通过比较荧光成像定量的总质量来验证该方法带有全部施加的染料量。为了量化染料的溶解量，将使用Hydrus-1D水平流模拟获得的毫米级分布水含量乘以映射的染料溶液浓度。染料浓度的空间分布通过荧光成像技术在像素分辨率约为100μm的范围内可视化和量化。使用校准的Freundlich吸附模型可得出亚毫米级的吸附染料浓度分布图。吸附等温线预测大多数染料被吸附到土壤中。总共有1366μg染料通过涂覆的基质块转移，其中1,181μg吸附在土壤上。通过比较应用和回收的Na-荧光素质量验证了该方法的适用性，相对紧密地对应。尽管此处介绍的方法的测试受到水含量和堆积密度的局部不确定性的限制，但该方法可用于绘制完整土壤块中染料的二维水平分布图，以量化大孔-基体传质。反应性溶质。