背景:在环境监测和核应急领域,为了获得铀酰引起的环境污染和核事故的相关信息,有必要建立一种快速定量的铀酰离子分析技术。作为一种新的有前途的技术,表面增强拉曼散射(SERS)有望实现这一目标。然而,在酸性条件下,铀酰离子很容易从SERS底物中解吸,强酸性水溶液中SERS基底的结构将被破坏。此外,SERS对铀酰离子的定量检测能力有待提高。因此,有必要开发新的SERS基底,以准确定量检测环境水样中的痕量uranyl,尤其是在酸性溶液中。
结果:在这项工作中,制备了银离子/海藻酸钠超分子水凝胶膜(Ag+/SASMH膜),在激光照射下,膜中的Ag离子转化为Ag/Ag2O复合纳米颗粒。在Ag纳米颗粒的电磁增强与铀酰和Ag2O之间的电荷转移增强的协同作用下,铀酰的拉曼信号强烈增强。利用SA的峰(550cm-1)作为内标,由于铀酰浓度从1.0×10-8molL-1到2×10-6molL-1具有良好的线性关系,因此可以实现LOD为6.7×10-9molL-1的定量检测。此外,外来金属离子几乎不影响铀的SERS检测,该底物可以测定天然水样中的痕量铀酰。特别是,酸度对铀酰离子的SERS信号无明显影响。因此,除了检测天然水样中的铀酰离子,所提出的策略还可以检测强酸性溶液中的铀酰离子。
■首次使用简单的一步法制备了用于快速定量检测铀酰离子的Ag/SASMH膜。所提出的底物通过将铀酰离子固定在水凝胶结构中,在酸性条件下成功检测到铀酰离子。与以前的研究相比,通过使用内标实现了对铀酰离子的更准确的定量分析,所提出的策略可以确定天然水样品或强酸性溶液中的痕量铀酰。
BACKGROUND: In the fields of environmental monitoring and nuclear emergency, in order to obtain the relevant information of uranyl-induced environmental pollution and nuclear accident, it is necessary to establish a rapid quantitative analytical technique for uranyl ions. As a new promising technique, surface-enhanced Raman scattering (SERS) is hopeful to achieve this goal. However, uranyl ions are easily desorbed from SERS substrates under acidic conditions, and the structures of SERS substrates will be destroyed in the strong acidic aqueous solutions. Besides, the quantitative detection ability of SERS for uranyl ions needs to be promoted. Hence, it is necessary to develop new SERS substrates for accurate quantitative detection of trace uranyl in environmental water samples, especially in acidic solutions.
RESULTS: In this work, we prepared silver ions/sodium alginate supramolecular hydrogel membrane (Ag+/SA SMH membrane), and the Ag+ ions from the membrane were transformed into Ag/Ag2O complex nanoparticles under laser irradiation. The Raman signal of uranyl was strongly enhanced under the synergistic interaction of electromagnetic enhancement derived from the Ag nanoparticles and charge transfer enhancement between uranyl and Ag2O. Utilizing the peak of SA (550 cm-1) as an internal standard, a quantitative detection with a LOD of 6.7 × 10-9 mol L-1 was achieved due to a good linear relation of uranyl concentrations from 1.0 × 10-8 mol L-1 to 2 × 10-6 mol L-1. Furthermore, foreign metal ions hardly affected the SERS detection of uranyl, and the substrate could determine trace uranyl in natural water samples. Particularly, the acidity had no obvious effect on SERS signals of uranyl ions. Therefore, in addition to the detection of uranyl ions in natural water samples, the proposed strategy could also detect uranyl ions in strong acidic solutions.
UNASSIGNED: A simple one-step method was used to prepare an Ag+/SA SMH membrane for rapid quantitative detection of uranyl ions for the first time. The proposed substrate successfully detected uranyl ions under acidic conditions by immobilizing uranyl ion in hydrogel structure. In comparison with the previous studies, a more accurate quantitative analysis for uranyl ions was achieved by using an internal standard, and the proposed strategy could determine trace uranyl in either natural water samples or strong acidic solutions.