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Updated: May 8, 2026
Two-Dimensional Visualization and Quantification of Labile, Inorganic Plant Nutrients and Contaminants in Soil
Published on: September 1, 2020
Diffusive gradients in thin films technique equipped with a mixed binding gel for simultaneous measurements of
Di Xu1, Yifei Chen, Shiming Ding
1State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Abstract:
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.
