Diffusive gradients in thin films (DGT) have gained wide attention for in situ measurement of reactive phosphorus species (PO4) in natural water, sediments and potentially soils. In this study, a novel Mg(OH)2 binding gel was formed using magnesium hydroxide obtained by in situ hydration of calcined magnesium oxide. Laboratory scale experiments showed that the novel Mg(OH)2 gel had a homogeneous dispersion of fine particles of Mg(OH)2 with a particle size of 2-5 μm. With 10 mL of 2.0 mol L-1 NaOH as the eluting agent, the optimal elution efficiency of PO4 on the Mg(OH)2 gel was 72 ± 5%. There were linear relationships between the accumulated PO4 mass and the applied PO4 concentration (0.1 to 20 mg P per L), time (0 to 24 h) and temperature (22 to 40 °C). The capacity of the Mg(OH)2 binding layer was determined to be 99.5 μg P per disc. Tests in synthetic seawater, Chaohu Lake and Yihai Pond confirmed that Mg(OH)2-DGT was able to accurately measure phosphorus up to 10 days. This was indicated by the good agreements between the concentrations measured by DGT (CDGT) technology and by an ex situ chemical method in solution (Csoln), with a CDGT/Csoln ratio between 0.91 and 1.09.

中文翻译：

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一种新颖的基于Mg（OH）2结合层的DGT技术，用于测量水和沉积物中的磷。

薄膜中的扩散梯度（DGT）在原位测量天然水，沉积物和潜在土壤中的活性磷物质（PO4）引起了广泛关注。在这项研究中，使用通过煅烧氧化镁原位水合获得的氢氧化镁形成了新型的Mg（OH）2结合凝胶。实验室规模的实验表明，新型Mg（OH）2凝胶具有粒径为2-5μm的Mg（OH）2细颗粒均匀分散。以10 mL 2.0 mol L-1 NaOH作为洗脱剂，PO4在Mg（OH）2凝胶上的最佳洗脱效率为72±5％。累积的PO4质量与所施加的PO4浓度（每升0.1至20 mg P），时间（0至24小时）和温度（22至40°C）之间存在线性关系。Mg（OH）2结合层的容量确定为每张光盘99.5μgP。在合成海水，巢湖和宜海池塘中进行的测试证实，Mg（OH）2-DGT能够准确测量长达10天的磷。DGT（CDGT）技术测得的浓度与溶液中非原位化学方法（Csoln）的良好一致性表明了这一点，CDGT / Csoln之比在0.91至1.09之间。