Atomic coprecipitation preconcentration systems

Chen, H., Jin, J. and Wang, Y., 1997, Flow- injection on-line Coprecipitation-preconcentration System Using Copper (II) diethyldithiocarbamate as Carrier for Flame Atomic Absorption Spectrometric Determination of Cadmium, Lead and Nickel in Environmental Samples, Analytica Chimica Acta, 353, 181-188. 

Hengwu, C., Jincao, J., and Yufeng, W. (1997) Flow injection on-line coprecipitation-preconcentration system using copper(II) diethyldithiocarbamate as carrier for flame atomic absorption spectrometric determination of cadmium, lead and nickel in environmental samples. AwaZ. Chim. Acta, 353,181-8. 

Z.-L. Fang, M. Sperling, B. Welz, Flame atomic-absorption spectrometric determination of lead in biological samples using a flow-injection system with online preconcentration by coprecipitation without filtration, J. Anal. At. Spectrom. 6 (1991) 301. 

A wide variety of inorganic materials have been used to precipitate or collect trace metals from solution. The most direct approach is a cementation process, which is one that removes the trace pollutants from solution by reduction with a metal and plating onto that metal surface. Although this process may be slow, the filtration is usually quick, since decantation is often sufficient. Finely divided cadmium extracts copper, selenium, and mercury from nitric and sulfuric acid solutions (66). When copper was used to preconcentrate mercury from water or biological fluids prior to atomic absorption analysis, the detection limit was 1-2 X 10 g (67, 68). Iron (69), zinc (70), and tungsten (71), as metals, have also been used to obtain a deposit of several trace metals from aqueous systems as dilute as 10 ppb for subsequent analysis. Elemental tellurium can be produced in solution by reduction using tin(II) chloride or sulfur dioxide, and coprecipitates silver (72) and selenium (73). Granulated silicon-metal alloys were used to remove metal ions from water and brine by reduction as well (74, 75). 

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