Metal speciation by supercritical fluid extraction with on-line detection by atomic absorption spectrometry.
Metal speciation by supercritical fluid extraction with on-line detection by atomic absorption spectrometry.
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DOI：
10.1021/ac00094a010
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发表时间：
1994-11
影响因子：
7.4
通讯作者：
J. Wang;W. D. Marshall
中科院分区：
文献类型：
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作者：
J. Wang;W. D. Marshall
描述了二氧化硅火焰管接口，用于通过 AAS 灵敏检测超临界 (SC) 流体萃取器洗脱液中的 As、Cd、Cu、Mn、Pb、Se 或 Zn。在操作中，水介质中的分析物金属通过与二丁基二硫代氨基甲酸四丁基铵 (TBADB-DTC) 进行原位络合而衍生化，并将产物络合物转移到 SC-CO2 中。无论流动相在过程的静态预平衡阶段用络合剂预饱和，还是当流动相流过与萃取容器串联的饱和容器时动态溶解该试剂，萃取过程都同样有效。 SC-CO2 提取器洗出液被雾化成扩散火焰，该火焰维持在火焰管和光学管接口的上部区域内。通过将 O2 和 H2 分别流到火焰管底部来维持的最佳火焰条件对于水和 SC-CO2 流动相来说略有还原性，但对于甲醇流动相来说略有氧化性。对于每种分析物元素，如果将标准液注入流动相，则检测限为亚纳克至低皮克。这些灵敏度允许探索不同基质中分析物金属的动员速率的差异，作为探测分析物金属与基质相互作用的技术。在没有络合剂的情况下，新鲜牛肝浆液中总锌含量的一部分被快速动员，其余部分比该组织的冻干标准参考材料中的锌溶解得更快。
A silica flame-in-tube interface is described for the sensitive detection, by AAS, of As, Cd, Cu, Mn, Pb, Se, or Zn in supercritical (SC) fluid extractor eluate. In operation, analyte metal in aqueous medium is derivatized by in situ complexation with tetrabutylammonium dibutyldithiocarbamate (TBADB-DTC) and the product complex is mobilized into SC-CO2. The extraction process is equally efficient whether the mobile phase is presaturated with complexing agent during a static preequilibration stage of the process or this reagent is solubilized dynamically as the mobile phase traverses a saturation vessel placed in series with the extraction vessel. SC-CO2 extractor eluate is nebulized into a diffused flame maintained within the upper region of the flame tube and the optical tube of the interface. Optimal flame conditions maintained with separate flows of O2 and H2 to the base of the flame tube are slightly reducing for aqueous and SC-CO2 mobile phases but slightly oxidizing for a methanolic mobile phase. For each analyte element, limits of detection were subnanogram to low picogram if standard was flow injected into the mobile phase. These sensitivities permitted differences in the rates of mobilization of analyte metal from different matrices to be explored as a technique for probing the interactions of the analyte metal with the matrix. A portion of the total Zn burden of fresh bovine liver slurry was rapidly mobilized in the absence of complexing agent, and the remainder was solubilized more rapidly than the Zn in a freeze-dried standard reference material of this tissue.