School of Geography, Earth and Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Anal Chim Acta. 2009 Nov 23;655(1-2):80-5. doi: 10.1016/j.aca.2009.09.046. Epub 2009 Oct 6.
A miniaturized diffusive gradients in thin films (DGT) device with a sampling window which is 16 times smaller than the conventional DGT device was developed. Its main advantage is the reduced volume of solution necessary for deployment, which extends its potential applications. The design of the miniaturized DGT device was also improved compared with the conventional DGT device, such that the area of the diffusive gel layer that allows the diffusion of metal towards the binding gel layer has the same diameter as the opening in the cap of the device and no additional metal is accumulated due to lateral diffusion as is the case for the conventional device. A good correlation between the metal concentration directly measured and the concentration estimated with the help of the DGT equation was obtained using this device in synthetic solutions (10 microg L(-1) Cd, 0.01 M NaNO(3), pH 6). The capacity of the device for Cd was approximately 20 microg, potentially allowing long term measurements to be performed. Metal accumulation increased linearly with deployment time up to 28 h and showed the theoretically expected dependence on diffusive layer thickness. The diffusive boundary layer thickness of approximately 0.2 mm in stirred solution was considered for accurate quantification of concentration. There was no difference between concentrations of labile metal measured in natural waters using the new miniaturised devices and the conventional devices.
一种微型扩散梯度薄膜（DGT）装置被开发出来，其采样窗口比传统 DGT 装置小 16 倍。它的主要优点是减少了部署所需的溶液体积，从而扩展了其潜在的应用。与传统的 DGT 装置相比，微型 DGT 装置的设计也得到了改进，使得允许金属向结合凝胶层扩散的扩散凝胶层的面积与装置帽盖上的开口直径相同，并且由于侧向扩散，不会像传统装置那样积累额外的金属。在合成溶液中（10 μg L(-1) Cd、0.01 M NaNO(3)、pH 6），使用该装置直接测量金属浓度和使用 DGT 方程估算的浓度之间得到了很好的相关性。该装置对 Cd 的容量约为 20 μg，可能允许进行长期测量。金属积累随部署时间呈线性增加，直至 28 小时，并且表现出与扩散层厚度理论上预期的依赖性。在搅拌溶液中，扩散边界层厚度约为 0.2 mm，用于准确量化浓度。使用新型微型装置测量天然水中的生物可利用金属浓度与传统装置没有差异。
