高级检索

    沉积物中重金属形态分析技术的适用范围

    Applicable Scope of Techniques in Speciation Analysis for Heavy Metals in Sediments

    • 摘要: 对沉积物中重金属形态分析的各种方法的适用性以及适用范围进行了探讨与总结。单一提取法的各提取剂中去离子水与中性盐溶液适用于预估生物毒性,稀酸可用作分析重金属的地球化学活性,螯合剂更适用于测量生物有效性。单一提取法不适用于碱性且重金属含量少的沉积物,且在试验时应选用参考性强的溶液。连续提取法能够提供更多的元素形态信息,然而由于提取剂的选择性较差,应尽可能选用参考性强的BCR或Tessier法进行“比较性”研究。在使用场流分级法和尺寸排阻色谱法对细小颗粒与胶体上基于粒度分离重金属时,移动相浸提剂的选择尤为重要。试验前应通过预实验了解样品的主要理化性质,以尽可能减少重金属形态发生改变的机率与程度(引用文献91篇)。

       

      Abstract: A summary and approach was made to the applicable scope of various techniques in chemical speciation of heavy metals in sediments. Among various extractants used in single extraction process, deionized water and neutral salt solutions are suitable for evaluation of biotoxicity, dilute acid solution scan be used in analysis of geochemical activity of heavy metals, and chelating reagents are preferred in determination of bio-availability. The single extraction process is not suitable for use in treatment of alkaline sediments with low contents of heavy metals. More information on species of the elements can be obtained by the successive extraction process, however, due to the low selectivity of extractants used in the process, "comparative study" by selecting the BCR method or the Tessier method which are high in referential ability, should be made. In the separation of heavy metal particles adhered on fine particles or colloids of sediments by the Field Flow Fractionation or by the Size Exclusion chromatography, choice of eluants (acting as the mobile phase) is ultra-important. Before the process of extraction, main physical and chemical properties of the sample should be well-known by pre-testings, so as to reduce the probablity and magnitude of change of chemical species of the heavy metals as far as possible (91 ref. cited).

       

    /

    返回文章
    返回