Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique.
Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique.
复制标题
DOI：
10.1016/s1001-0742(12)60140-5
复制
发表时间：
2013-08
影响因子：
6.9
通讯作者：
Qin Sun;Yifei Chen;Di Xu;Yan Wang;S. Ding
中科院分区：
文献类型：
--
作者：
Qin Sun;Yifei Chen;Di Xu;Yan Wang;S. Ding
最近开发了基于水合氧化锆（Zr-氧化物）的薄膜扩散梯度（DGT）技术，用于测量溶解的活性磷酸盐（DRP）。在这项研究中，报告了 DGT 技术的详细性能。加标实验表明，几种正磷酸单酯化合物有助于 DRP 的氧化锆 DGT 测量。然而，由于典型天然水中有机磷浓度较低，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）、SO2−4（高达16 g/L）、HCO−3（高达817 g/L）以及AsO−2和AsO3−4（均高达1 mg As/L）的存在对DRP测量的影响可以忽略不计。 Cl−、SO2−4 和 HCO−3 的阈值浓度较之前使用其他基于吸附剂的 DGT 技术测量 DRP 的报告有所增加。 DRP 的 DGT 测量能力随着溶液 pH 值 (4.2–9.2) 的增加而降低。最低容量（pH 9.2 时为 95 μg P/cm2）仍然大于通常用于测量 DRP 的其他 DGT 技术（2–12 μg P/cm2）。氧化锆结合凝胶可保存长达2年而无任何老化影响。该有效期比目前 DGT 装置中常用的水铁矿结合凝胶（6 个月）长得多。现场应用表明，氧化锆DGT技术测得的三个淡水样品中DRP的浓度与传统比色法的结果一致。
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), SO2−4(up to 16 g/L), HCO−3(up to 817 g/L), and AsO−2and AsO3−4(both up to 1 mg As/L) in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl−, SO2−4and HCO−3have 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 μg P/cm2at pH 9.2) was still greater than that of other DGT techniques that are usually used for the measurement of DRP (2–12 μg 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.