Study on Preconcentration Methods for the Determination of Trace Elements

(1)双硫腙-TOPO协同萃取体系用于铜(II)的预富集。TTA和1，10-邻菲咯啉对稀土元素的协同萃取不仅提高了分离系数，而且提高了萃取效率。建立了在线萃取系统，用于痕量金属的电感耦合等离子体分析。采用络合剂混合萃取法同时萃取多种元素。(2)采用Bio-Rad AG-1树脂预富集海水中的铀和钼。开发了系列螯合树脂，并将其应用于稀有金属的富集。分别用MBT/SG和硫氰酸酯/SG浓缩银和锑。聚三氟氯乙烯吸附了多种金属络合物，应用于天然水中痕量金属的形态和预富集。采用ExPAPIERF-2富集Th、Zr、Fe、Sc、Y、Ga和RE等元素。(3)研究了分子双层组装体对金属的预富集。(4)采用In(III)处理的Amberlite XAD-2树脂对腐植酸络合物进行预富集，建立了共沉淀-浮选技术，测定了腐植酸的分子量分布和吸附能力。(5)研究了非水等速分离分离重金属离子的方法。

(1) Synergistic extraction system, dithizone-TOPO, was applied to preconcentration of Cu(II). Synergistic extraction of RE elements using TTA and 1,10-phenanthroline was found to improve not only separation factor but extraction efficiency. The online extraction system was developed for ICP analysis of trace metals. Extraction with chelating-agents mixture was used for simultaneous multi-elements extraction.(2) Bio-Rad AG 1 resin was used for preconcentration of U and Mo from seawater. The series of chelating resins was developed and applied to enrich the rare metals. MBT/SG and thionalide/SG were used for concentration of Ag and Sb, resevtively. Poly(chlorotrifluoroethylene) was found te adsorb many metal complexes and applied to speciation and preconcentration of trace metals in natural waters. "EXPAPIERF-2" was used for enrichment of Th, Zr, Fe, Sc, Y,Ga and RE elements.(3) Metal preconcentration by molecular bilayer assemblies was studied.(4) Amberlite XAD-2 resin treated with In(III) was used for preconcentration of humic complexes and coprecipitation-flotation technique was developed to measure the molecular weight distribution and adsorption ability of humic acid.(5) Metal concentration with non-aqueous isotachophoresis was studied for separation of heavy metal ions after extraction of the DDTC chelates into nitrobenzene.