Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
J Environ Sci (China). 2013 Aug 1;25(8):1592-600. doi: 10.1016/s1001-0742(12)60140-5.
A diffusive gradients in thin films (DGT) technique based on hydrous zirconium oxide (Zr-oxide) has been recently developed for the measurement of dissolved reactive phosphate (DRP). In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- (up to 106 g/L), SO4(2-) (up to 16 g/L), HCO3- (up to 817 g/L), and AsO2- and AsO4(3-) (both up to 1 mg As/L) in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO4(2-) and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH (4.2-9.2). The lowest capacity (95 microg P/cm2 at pH 9.2) was still greater than that of other DGT techniques that are usually used for the measurement of DRP (2-12 microg P/cm2). The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices (6 months). The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.
一种基于水合氧化锆（Zr-oxide）的扩散梯度薄膜（DGT）技术最近被开发用于测量溶解反应性磷酸盐（DRP）。本研究详细报告了 DGT 技术的性能。加标实验表明，几种正磷酸盐单酯化合物对 DGT 测量 DRP 有贡献。然而，由于典型天然水中有机磷的浓度较低，这种现象在野外条件下不太可能发生。溶液中 Cl-（高达 106 g/L）、SO4(2-)（高达 16 g/L）、HCO3-（高达 817 g/L）以及 AsO2-和 AsO4(3-)（均高达 1 mg As/L）的存在对 DRP 的测量几乎没有影响。与使用其他基于吸附剂的 DGT 技术测量 DRP 相比，Cl-、SO4(2-)和 HCO3-的阈值浓度有所增加。用于测量 DRP 的 DGT 测量的容量随着溶液 pH 值（4.2-9.2）的增加而降低。在 pH 9.2 时，最低容量（95 microg P/cm2）仍大于通常用于测量 DRP 的其他 DGT 技术（2-12 microg P/cm2）。Zr-oxide 结合凝胶在没有任何老化影响的情况下可储存长达 2 年。这段有效期明显长于目前 DGT 设备中常用的水铁矿结合凝胶（6 个月）。野外应用表明，使用 Zr-oxide DGT 技术测量的三种淡水样品中的 DRP 浓度与传统比色法的测量结果一致。
