Cuprite-modified electrode for the detection of iodide species

A cuprite-modified carbon paste electrode was evaluated as an electrochemic al sensor for iodide species in aqueous medium. The overall analysis involv ed a two-step procedure: an open-circuit accumulation step followed by volt ammetric quantification. In the preconcentration step, iodide was accumulat ed on cuprite (Cu2O) according to a surface precipitation mechanism leading to the formation of CuI. This solid was then detected either in the cathod ic or in the anodic mode, the first process allowing multiple successive an alyses without requiring any regeneration of the electrode surface, while t he anodic scan resulted in the surface oxidation of Cu2O requiring the rene wal of the electrode surface before any further accumulation experiment. Th e influence of various experimental parameters on the sensor response was i nvestigated (i.e., pH, preconcentration time, detection mode, iodide concen tration, Cu2O content into the paste). Reproducible results were obtained a fter optimization: a linear calibration was obtained in the 1 x 10(-6) M to 2 x 10(-5) M concentration range, with a detection Limit of 5 x 10(-7) M. The effect of chloride interference was also discussed. (C) 1999 Elsevier S cience S.A. All rights reserved.