caa a22 4500 467995427 CHVBK 20180323112555.0 cr unu---uuuuu 170328e19900701xx s 000 0 eng 10.1007/BF01244760 doi (NATIONALLICENCE)springer-10.1007/BF01244760 Determination of subnanomolar concentrations of tungsten (VI) by catalytic adsorption polarography [Elektronische Daten] [Balazs Magyar, Hans Elsener, Samuel Wunderli] A new differential pulse polarographic method for the determination of W(VI) using a catalytic adsorption wave is described. W(VI) is first chelated by 7-iodo-8-hydroxyquinoline-5-sulfonic acid at pH 0.5. The complex ion formed is strongly adsorbed on the surface of a dropping mercury electrode. At a potential of −0.95 V versus the Ag/AgCl (3M KCl) reference electrode the adsorbed complex is reduced by the polarographic current and oxidized very fast by hydrated hydrogen ions providing the oxidized form of the complex ion for repeated redox cycles. As the redox process taking place in the electric double layer, the diffusion of the complex does not limit the polarographic current. Therefore, high currents occur, and consequently, a very high sensitivity is obtained. The practical detection limit (PDL) is 3.7 ng W/kg solution corresponding to 2 × 10−11 M. The standard deviation of single values is 1.2 ng/kg at the concentration of 91 ng/kg lying in the middle of the linear part of the calibration curve. Because Mo (VI) gives a very similar catalytic adsorption wave, serious mutual interferences occur in the analysis of mixtures of both species. An effective separation of Mo(VI) was worked out. Using 1% (w/v) solution of trioctylphosphinoxide in kerosene, Mo(VI) can almost completely be extracted from 1.8M HCl with a threefold extraction resulting in a separation factor of 40000. Springer-Verlag, 1990 trace analysis nationallicence tungsten nationallicence catalytic adsorption polarography nationallicence liquid-liquid extraction nationallicence molybdenum nationallicence Magyar Balazs Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092, Zürich, Switzerland aut Elsener Hans Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092, Zürich, Switzerland aut Wunderli Samuel Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092, Zürich, Switzerland aut Microchimica Acta Springer-Verlag 102/4-6(1990-07-01), 179-189 0026-3672 102:4-6<179 1990 102 604 https://doi.org/10.1007/BF01244760 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01244760 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Magyar Balazs Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092, Zürich, Switzerland aut NATIONALLICENCE 700 1- Elsener Hans Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092, Zürich, Switzerland aut NATIONALLICENCE 700 1- Wunderli Samuel Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092, Zürich, Switzerland aut NATIONALLICENCE 773 0- Microchimica Acta Springer-Verlag 102/4-6(1990-07-01), 179-189 0026-3672 102:4-6<179 1990 102 604 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer