水环境中基于分离-富集的金属形态分析方法研究进展

Separation-preconcentration based metal speciation analysis in aquatic environment

金属的形态对其在环境介质中的迁移转化、生物有效性和毒性具有重要影响.目前认为,金属的自由离子态和不稳定络合态是具有潜在生物有效性的形态,而纳米颗粒的存在使得具有生物有效性的金属形态变得更为复杂.痕量金属和纳米颗粒在天然水环境中的含量较低,大部分检测方法无法达到检测限要求.基于分离-富集的金属形态分析方法因检测限低、操作简单、结果可靠等优点被广泛用于环境中痕量金属及纳米颗粒存在下金属的形态分析.本文从原理、应用条件和优缺点等方面对梯度扩散薄膜技术、唐南渗析膜技术、离子交换技术和渗透液膜技术等基于分离-富集的金属形态分析方法进行综述,为水环境中金属形态分析方法的选择提供了参考和依据.

The speciation of metals plays a vital role in their migration, transformation, bioaccumulation and toxicity in natural environment. Among all metal species, free ion and labile metal complexes are the potentially bioavailable forms of metal. Besides, the presence of nanoparticles further complicates the bioavailable speciation of metals. Due to the low concentrations of trace metals and nanoparticles in aquatic environment, most of the detection methods cannot meet required detection limit. The separation-preconcentration techniques, including diffuse gradients in thin-films technique, Donnan membrane technique, ion exchange technique and permeation liquid membrane, have been widely applied in speciation analysis of trace metals and nanoparticles due to their low detection limit, simple operation and reliable results. In this short review, we summarized principles, application conditions, advantages and disadvantages of four separation-preconcentration based speciation analysis methods, in order to provide scientific supports for the application of metal speciation analysis in aquatic environment.