Diffusive gradients in thin films technique equipped with a mixed binding gel for simultaneous measurements of dissolved reactive phosphorus and dissolved iron.
Diffusive gradients in thin films technique equipped with a mixed binding gel for simultaneous measurements of dissolved reactive phosphorus and dissolved iron.
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DOI：
10.1021/es401822x
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发表时间：
2013-08
影响因子：
11.4
通讯作者：
Di Xu;Yifei Chen;S. Ding;Qin Sun;Yan Wang;Chaosheng Zhang
中科院分区：
文献类型：
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作者：
Di Xu;Yifei Chen;S. Ding;Qin Sun;Yan Wang;Chaosheng Zhang
发展一种同时跟踪沉积物中磷（P）和铁（Fe）释放的技术，将有助于加深我们对水系统中磷和铁循环耦合的内部负荷过程的理解。在这项研究中，建立了一种新的技术，同时测量溶解的活性磷（DRP）和溶解铁主要从沉积物中释放的薄膜扩散梯度（DGT）理论的基础上。以非晶氢氧化锆（ZrO_2）和Chelex-100树脂为结合剂，研制了一种用于组装DGT的混合结合凝胶（ZrO-Chelex凝胶），用于同时吸附DRP和溶解的Fe（II）。DRP和溶解的Fe（II）与ZrO-Chelex DGT的同时测量在溶液中进行了验证，并在正常环境中的溶液pH值和离子强度是独立的。ZrO-Chelex DGT测定DRP和溶解态Fe（Ⅱ）的容量分别为90 μg·cm ~（-2）和75 μg·Fe·cm ~（-2），后者大于常用于金属DGT测定的Chelex-100树脂DGT的容量（45 μg·Fe·cm ~（-2））。微观实验进一步证实了ZrO-Chelex DGT同时测量沉积物中P和Fe的可行性，由于该方法与Chelex-100树脂DGT相比具有更高的容量，因此可以测量更高浓度的Fe。
Developing a technique to track the release of phosphorus (P) and iron (Fe) simultaneously in sediments would be very useful in deepening our understanding of the internal loading process of P coupled with Fe cycling in aquatic systems. In this study, a new technique was established to measure simultaneously the dissolved reactive P (DRP) and dissolved Fe primarily released from sediment solids based on the diffusive gradients in thin films (DGT) theory. A mixed binding gel (ZrO-Chelex gel) used for assembling DGT was developed for simultaneous uptake of DRP and dissolved Fe(II) using amorphous zirconium hydroxide (Zr-oxide) and Chelex-100 resin as binding agents. Simultaneous measurements of DRP and dissolved Fe(II) with the ZrO-Chelex DGT were validated in solution and were independent of solution pH and ionic strength in normal environments. The capacities of the ZrO-Chelex DGT for measurements of DRP and dissolved Fe(II) were 90 μg P cm(-2) and 75 μg Fe cm(-2), with the latter being greater than that (45 μg Fe cm(-2)) observed with the Chelex-100 resin DGT commonly used in DGT measurements of metals. Microcosm experiments further confirmed the feasibility of the ZrO-Chelex DGT for simultaneous measurement of P and Fe in sediments, with a higher concentration of Fe being measured due to this method's higher capacity compared with the Chelex-100 resin DGT.