Electrochemical characterization of nickel electrodes in

Electrochemical characterization of nickel electrodes in
phosphate and carbonate electrolytes in view of assessing a
medical diagnostic device for the detection of early diabetes
Electroanalysis. DOI:10.1002/elan.201000307
Hanna Ayoub a,b, Sophie Griveau a, Virginie Lairb, Philippe Brunswickc, Michel Cassirb, Fethi
Bedioui a
a
Unité Pharmacologie Chimique et Génétique et Imagerie, CNRS8151/ INSERMU1022/
Université Paris Descartes/Chimie ParisTech, 11 rue Pierre et Marie Curie, 75231 Paris
cedex05, France
b
Laboratoire d’Electrochimie, Chimie des Interfaces et Modélisation pour l’Energie CNRS
UMR 7575, Chimie ParisTech, 11rue Pierre et Marie Curie, 75213 Paris cedex 05, France
c
Impeto Medical, 17 rue campagne Première, 75014 Paris, France
ABSTRACT
Optimizing a multi-electrode device using proprietary technology for non invasive
assessment of eccrine sweat gland activity and thus the early detection of diabetes. We
thoroughly explored the electrochemical behavior of a nickel electrode in a three-electrode
setup combining a nickel counter electrode and a nickel pseudo-reference electrode in
synthetic buffered phosphate and carbonate solutions in presence of chloride, lactate and
urea that mimic the composition of physiological sweat. This approach provides insight into
the origin of the onset of responses measured upon the application of low voltage potential
with variable amplitudes to Ni electrodes on the skin. For low voltage amplitude of ca.
DE=0.6V, the electrochemical reactions measured at the electrodes are those related to the
oxidation of Ni leading to the formation of a passive layer, as well as the reduction of this
passive layer. For voltage amplitude higher than 1V, or current densities higher than
1mA/cm2, the breakdown of the passive layer becomes the main electrochemical anodic
reaction, while its reduction and the electrolytic solution govern the cathode reactions. This
brings explanation of the non linear current-voltage features measured during the clinic
tests. Finally, the obtained results make possible the definition of the experimental
electrochemical conditions where the Ni electrodes can be renewed.