caa a22 4500 469129492 CHVBK 20180323133200.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF00324981 doi (NATIONALLICENCE)springer-10.1007/BF00324981 Speciation of Cr(VI)/Cr(III) by electrothermal atomisation AAS after electrodeposition on a L'vov platform [Elektronische Daten] [Juan Vidal, José Sanz, Juan Castillo] Summary: The pyrolysed graphite L'vov platform of a tube furnace is considered as an electrode for the electrodeposition and speciation of chromium by electrothermal atomisation atomic absorption spectrometry (ETA-AAS). Firstly, a preliminary study of the Cr(VI)/Cr(III) voltammetric behavior at pH 4.70 on a glassy-carbon electrode is carried out. Secondly, the L'vov platform is used as a cathodic macro-electrode for the selective preconcentration of Cr(VI)/Cr(III) on a mercury film. Speciation of Cr(VI)/Cr(III) is carried out on the basis of the electrolysis potential (Ee): at pH 4.70 and Ee=−0.30 V, only Cr(VI) is reduced to Cr(III) and accumulated as Cr(OH)3 by adsorption on a mercury film; at Ee=−1.80 V both Cr(VI) and Cr(III) are accumulated forming an amalgam with added mercury(II) ions. Once the film has been formed, the platform is transferred to a graphite tube to atomise the element. The reliability of the method was tested for the speciation of chromium in natural waters and it proves to be highly sensitive thanks to the electroanalytical step. In all samples, the Cr(VI) concentration was less than the detection limit (0.15 ng ml−1), and the concentration of Cr(III) agrees with those of total chromium. The analytical recovery of Cr(VI) added to water samples [3.50 ng ml−1 of Cr(VI)] was 105±6.2%. Springer-Verlag, 1992 Vidal Juan Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E-50009, Zaragoza, Spain aut Sanz José Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E-50009, Zaragoza, Spain aut Castillo Juan Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E-50009, Zaragoza, Spain aut Fresenius' Journal of Analytical Chemistry Springer-Verlag 344/6(1992-06-01), 234-241 0937-0633 344:6<234 1992 344 216 https://doi.org/10.1007/BF00324981 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00324981 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Vidal Juan Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E-50009, Zaragoza, Spain aut NATIONALLICENCE 700 1- Sanz José Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E-50009, Zaragoza, Spain aut NATIONALLICENCE 700 1- Castillo Juan Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, E-50009, Zaragoza, Spain aut NATIONALLICENCE 773 0- Fresenius' Journal of Analytical Chemistry Springer-Verlag 344/6(1992-06-01), 234-241 0937-0633 344:6<234 1992 344 216 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer