São Paulo State University (Unesp), Environmental Studies Center, Av. 24-A, 1515, 13506-900, Rio Claro, SP, Brazil.
Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13083-970, Campinas, SP, Brazil.
Anal Methods. 2023 Jul 13;15(27):3310-3317. doi: 10.1039/d3ay00682d.
The diffusive gradients in thin films (DGT) technique pre-concentrates labile species of trace elements, giving time-integrated information about their labile concentrations. All previous DGT approaches for simultaneous uptake of cations and anions have used the hazardous polyacrylamide reagent to immobilize the binding phase. The present work proposes a diffusive layer of agarose and a mixed binding layer of ZrO and Chelex 100 immobilized in an agarose hydrogel to simultaneously determine the labile concentration of cations (Mn, Co, Ni, Cu, Zn and Cd) and anions (V, As, Se, Mo and Sb) in aquatic systems. The use of both layers using agarose instead of carcinogenic polyacrylamide as the hydrogel significantly reduces the costs and simplifies the manufacturing process. The proposed device was evaluated through recovery tests, deployment curves and pH/ionic strength tests. The mixed binding layer was compared with commercially available DGT devices for deployment in river water. The relationships between accumulated mass and time (24 h) was linear ( > 0.9) for all analytes. The diffusion coefficients obtained were consistent with the literature, ranging from 3.98 to 8.43 × 10 cm s. Except for Zn at pH 8.0, the obtained values of / were within the range of 1.00 ± 0.2 for the studied range of pH and for most ionic strengths. However, at low ionic strength, the concentrations of Mn, Co, Ni, Zn, V and Mo were underestimated. The concentrations of trace elements determined in river water using the proposed devices agreed with the labile concentrations determined by using commercial devices.
薄膜扩散梯度（DGT）技术预先浓缩痕量元素的生物可利用态，提供痕量元素生物可利用态浓度的时间积分信息。以前所有用于同时吸收阳离子和阴离子的 DGT 方法都使用危险的聚丙烯酰胺试剂来固定结合相。本工作提出了一种琼脂糖扩散层和ZrO 和 Chelex 100 的混合固定层，将其固定在琼脂糖水凝胶中，以同时测定水系统中阳离子（Mn、Co、Ni、Cu、Zn 和 Cd）和阴离子（V、As、Se、Mo 和 Sb）的生物可利用态浓度。使用琼脂糖代替致癌的聚丙烯酰胺作为水凝胶来使用两层，显著降低了成本并简化了制造过程。通过回收率测试、部署曲线和 pH/离子强度测试对所提出的装置进行了评估。将混合固定层与市售的 DGT 装置进行了比较，用于河水的部署。对于所有分析物，累积质量与时间（24 h）之间的关系都是线性的（>0.9）。获得的扩散系数与文献一致，范围为 3.98 至 8.43×10 cm s。除了 pH 8.0 时的 Zn 之外，获得的 / 值在研究的 pH 和大多数离子强度范围内为 1.00±0.2。然而，在低离子强度下，Mn、Co、Ni、Zn、V 和 Mo 的浓度被低估了。使用所提出的装置测定河水中痕量元素的浓度与使用商业装置测定的痕量元素生物可利用态浓度一致。
