Rosende Maria, Savonina Elena Yu, Fedotov Petr S, Miró Manuel, Cerdà Víctor, Wennrich Rainer
Department of Chemistry, Faculty of Sciences, University of the Balearic Islands, Carretera de Valldemossa Km. 7.5, E-07122 Palma de Mallorca, Illes Balears, Spain.
Talanta. 2009 Sep 15;79(4):1081-8. doi: 10.1016/j.talanta.2008.10.062. Epub 2008 Nov 14.
Dynamic fractionation has been recognized as an appealing alternative to conventional equilibrium-based sequential extraction procedures (SEPs) for partitioning of trace elements (TE) in environmental solid samples. This paper reports the first attempt for harmonization of flow-through dynamic fractionation using two novel methods, the so-called sequential injection microcolumn (SIMC) extraction and rotating coiled column (RCC) extraction. In SIMC extraction, a column packed with the solid sample is clustered in a sequential injection system, while in RCC, the particulate matter is retained under the action of centrifugal forces. In both methods, the leachants are continuously pumped through the solid substrates by the use of either peristaltic or syringe pumps. A five-step SEP was selected for partitioning of Cu, Pb and Zn in water soluble/exchangeable, acid-soluble, easily reducible, easily oxidizable and moderately reducible fractions from 0.2 to 0.5 g samples at an extractant flow rate of 1.0 mL min(-1) prior to leachate analysis by inductively coupled plasma-atomic emission spectrometry. Similarities and discrepancies between both dynamic approaches were ascertained by fractionation of TE in certified reference materials, namely, SRM 2711 Montana Soil and GBW 07311 sediment, and two real soil samples as well. Notwithstanding the different extraction conditions set by both methods, similar trends of metal distribution were in generally found. The most critical parameters for reliable assessment of mobilizable pools of TE in worse-case scenarios are the size-distribution of sample particles, the density of particles, the content of organic matter and the concentration of major elements. For reference materials and a soil rich in organic matter, the extraction in RCC results in slightly higher recoveries of environmentally relevant fractions of TE, whereas SIMC leaching is more effective for calcareous soils.
动态分馏已被认为是一种有吸引力的替代方法，可用于环境固体样品中痕量元素（TE）的分配，以替代传统的基于平衡的顺序萃取程序（SEP）。本文报道了首次尝试使用两种新方法来协调流通式动态分馏，即所谓的顺序注射微柱（SIMC）萃取和旋转盘柱（RCC）萃取。在SIMC萃取中，填充有固体样品的柱子被集成在顺序注射系统中，而在RCC萃取中，颗粒物在离心力作用下被保留。在这两种方法中，均使用蠕动泵或注射泵将淋洗剂连续泵入固体基质。选择五步SEP法，以1.0 mL min⁻¹的萃取剂流速，从0.2至0.5 g样品中分离出铜、铅和锌的水溶性/可交换态、酸溶性、易还原态、易氧化态和中度还原态组分，然后通过电感耦合等离子体原子发射光谱法对浸出液进行分析。通过对标准参考物质（即SRM 2711蒙大拿土壤和GBW 07311沉积物）以及两个实际土壤样品中的TE进行分馏，确定了两种动态方法之间的异同。尽管两种方法设定的萃取条件不同，但总体上发现金属分布趋势相似。在最坏情况下可靠评估TE可移动库的最关键参数是样品颗粒的尺寸分布、颗粒密度、有机质含量和主要元素浓度。对于标准参考物质和富含有机质的土壤，RCC萃取能使TE的环境相关组分回收率略高，而SIMC浸出对钙质土壤更有效。
