摘要:
不同沉积环境和沉积机制下进入海洋沉积物中的元素分别与不同介质结合,因此,将沉积物中不同结合形态元素相分离的顺序萃取方法是研究沉积物源和沉积环境的重要手段。以Tessier等建立的萃取流程为基础,针对深海沉积物标准物质GBW07315中Fe、Mn、Co、Cu、V元素,分析了方法的准确性和重复性。结果表明:各元素回收率基本介于94%~126%之间,平均值为106%。在重复性方面,除V元素在铁锰氧化物结合态中的相对标准偏差较高外,其余元素在铁锰氧化物结合态、有机结合态以及残渣态中的相对标准偏差均低于15%,而碳酸盐结合态和可交换态中元素的相对标准偏差较大,这与其样品中这些结合态的元素含量相对较低有关。因此,对于深海沉积物来讲,顺序萃取法具有较好的稳定性和可靠性,尤其是对其中铁锰氧化物结合态、有机结合态和残渣态的萃取效果令人满意。将该方法应用于冲绳海槽热液影响沉积物中,实现了热液源铁锰氧化沉积的有效萃取和分离。
Abstract:
In marine sediments,elements may occur as different speciations, i.e. they are combined with various fractions under different sedimentary environments and settling mechanisms. So the sequential extraction procedure, which partitions the elements in sediments among various forms, is an important tool for studying the sedimentary environments and material sources. In this study, based on the procedure established by Tessier et al in 1979,five elements (Fe,Mn,Co,Cu and V) in the deep sea sediment reference material GBW07315 are determined. The accuracy and repeatability of the method are also evaluated. The results show that the recovery rates vary between 94% and 126% for all the five elements, with an average of 106%. For Fe-Mn oxides fraction, organic fraction, and residual fraction, the relative standard devia-tions of four or five paralleling samples are lower than 15% for all elements, except for V in the Fe-Mn ox-ides fraction. However, for carbonate fraction and exchangeable fraction, a little higher deviations are found and should be attributed to the low concentrations of analyzed elements in these fractions. There-fore, this method is steady and dependable for the deep sea sediments, especially for the extraction of Fe-Mn oxides fraction, organic fraction, and residual fraction. This sequential extraction procedure is also applied to the hydrothermal influenced sediments from the middle Okinawa Trough, getting an effective extraction and separation of hydrothermal signatures.
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