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by Keyword: Hexavalent chromium


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Zazoua, A., Morakchi, K., Kherrat, R., Samar, M. H., Errachid, A., Jaffrezic-Renault, N., Boubellout, R., (2008). Electrochemical characterization of an EIS sensor functionalized with a TOPO doped polymeric layer for Cr(VI) detection IRBM , 29, (2-3), 187-191

A hexavalent chromium-selective sensor, based on polymeric membranes containing trioctylphosphine oxide (TOPO) deposited on a Si/Sio(2)/Si3N4 structure, has been developed. The ion-sensitivity of TOPO was investigated by capacitance measurements (C-V) and electrochemical impedance spectroscopy. A quasi-nernstian response for Cr2O72- exchange is shown. Selectivity coefficients and detection limits of Cr(VI) in the presence of interfering anions were determined experimentally using the fixed interference method. A detection limit of 10(-5) M of Cr(VI) is obtained even in presence of sulphate and chloride ions.

Keywords: Hexavalent chromium, Trioctylphosphine oxide, EIS, Siloprene membrane, Capacitance-voltage


Zazoua, A., Kherrat, R., Samar, M. H., Errachid, A., Jaffrezic-Renault, N., Bessueille, F., Leonard, D., (2008). Characterization of TBP containing polysiloxane membrane/insulator/semiconductor structures for hexavalent chromium detection Materials Science and Engineering: C-Biomimetic and Supramolecular Systems 5th Maghreb/Europe Meeting on Materials and Their Applications for Devices and Physical, Chemical and Biological Sensors (MADICA 2006) (ed. -----), Elsevier Science BV (Mahdia, Tunisia) 28, (5-6), 1014-1019

A hexavalent chromium-sensitive EMIS sensor (electrolyte membrane insulator semiconductor sensor) is prepared by deposition of a tributylphosphate (TBP) ionophore-containing siloprene membrane on a Si/SiO2/Si3N4 structure. The developed EMIS sensor was studied by means of impedance spectroscopy, capacitance-voltage, X-ray photoelectron spectrometry and FT-IR spectroscopy. From the flat-band shift of the EMIS structure, the nersntian response to the anionic species Cr2O7- was demonstrated. The linear range of detection is 10(-4) M to 10(-1) M and the detection limit is 10(-5) M. Sulfate and chloride anions are shown not to be interfering whereas carbonate ions present a pK(pot) equal to 0.19.

Keywords: Hexavalent chromium, EMIS sensor, Tributylphosphate, Siloprene membrane