This work presents a new method for determining iron-porphyrin-like complexes (Fe-Py) based on Continuous Flow Analysis (CFA) with chemiluminescence detection and its application to natural waters in an estuarine environment. The involved reaction is founded on luminol oxidation by hydrogen peroxide in the presence of Fe-Py complexes at pH 13. The detection limit is 7.2 pM hemin equivalent, the linear range extends to 150 nM and precision of the method is 6.4% at 0.25 nM (n = 8). This new method's detection limit is 15 times lower than the previous analytical procedure of Vong et al. (2007), based on Flow Injection Analysis (FIA) and using different chemical conditions. Moreover, the presented method is fast (90s/analysis), involves a low consumption of reagents, a small sample volume, and simplified sample handling. The method was applied to natural samples collected along the temperate macrotidal Aulne estuary (Bay of Brest, France). Here, we report for the first time on the spatial distribution of the Fe-Py complex concentration (dissolved, reactive particulate) over the entire salinity gradient of a macrotidal temperate estuary. The Fe-Py concentrations in the riverine and marine end-members were 0.873 ± 0.007 nM (S = 0.92) and 0.010 ± 0.004 nM (S = 34.86), respectively. Between these two salinities, non-conservative behaviour was observed, with an increase in Fe-Py concentrations to 1.142 ± 0.031 nM at S = 5.2 corresponding to the Maximum Turbidity Zone (MTZ), followed by a strong removal of Fe-Py in the salinity range 5–20. Then, the Fe-Py concentrations decreased linearly during mixing processes, reaching picomolar levels towards the coastal waters. The estimated entering flux from the river equaled 240 ± 2 g.d⁻¹ whereas the net flux to coastal sea waters was 95 ± 10 g.d⁻¹ leading to a loss of ~60%. The estuarine system globally acts as a sink for Fe-Py complexes, probably due to the aggregation of Fe-Py complexes on particles, to flocculation and/or sedimentation.

这项工作提出了一种基于化学发光检测的连续流动分析 (CFA) 确定类铁卟啉配合物 (Fe-Py) 的新方法，并将其应用于河口环境中的天然水体。所涉及的反应是建立在 pH 13 的 Fe-Py 配合物存在下，过氧化氢对鲁米诺的氧化。检测限为 7.2 pM 血红素当量，线性范围扩展到 150 nM，该方法的精密度在 0.25 nM 时为 6.4% ( n  = 8)。这种新方法的检测限比 Vong 等人以前的分析程序低 15 倍。(2007)，基于流动注射分析(FIA) 并使用不同的化学条件。此外，所提出的方法速度快（90 秒/分析），试剂消耗低，样品量小，样品处理简单。该方法应用于沿温带潮汐 Aulne 河口（法国布雷斯特湾）采集的自然样品。在这里，我们首次报告了在大潮温带河口整个盐度梯度上 Fe-Py 复合物浓度（溶解的、反应性颗粒）的空间分布。河流和海洋末端成员中的 Fe-Py 浓度分别为 0.873 ± 0.007 nM (S = 0.92) 和 0.010 ± 0.004 nM (S = 34.86)。在这两种盐度之间，观察到非保守行为，在 S = 5.2 对应于最大浊度区 (MTZ) 时，Fe-Py 浓度增加到 1.142 ± 0.031 nM，随后在 5-20 盐度范围内强烈去除 Fe-Py。然后，Fe-Py 浓度在混合过程中线性下降，向沿海水域达到皮摩尔水平。来自河流的估计进入通量等于 240 ± 2 gd^-1而沿海海水的净通量为 95 ± 10 gd ^-1导致约 60% 的损失。河口系统在全球范围内充当 Fe-Py 配合物的汇，可能是由于 Fe-Py 配合物在颗粒上的聚集、絮凝和/或沉降。